Mission
Members
Projects
Intensity Modulated Brachytherapy
Alana Thibodeau-Antonacci, Ph.D. Student & Marc Morcos, Ph.D. Student
The critical limitation with brachytherapy is the rotationally symmetric dose distribution provided by brachytherapy sources, delivering high dose to the tumor but often with poor tumor conformity due to the non-symmetrical shape of the tumors resulting in dose spillage to surrounding healthy tissues.
For example, large and irregular gynecological tumors, which extend into the parametrial and/or paravaginal tissues cannot be treated with curative intend by using intracavitary brachytherapy implants alone without overdosing nearby healthy organs causing side effects but must be supplemented with invasive interstitial high dose rate brachytherapy to enable conformal dose delivery to the tumor while reducing dose to healthy tissues. However, despite the excellent clinical results, this treatment is not available to all patients due to its invasive nature, lack of resources and trained radiation oncologists. For prostate cancer, disease-free survival is higher in patients treated with high dose rate brachytherapy combined with external beam radiotherapy compared to those treated with external beam radiotherapy alone.
Our group has developed the next generation of high dose rate brachytherapy technology, including prototype delivery systems for intensity modulated brachytherapy treatment of prostate, cervix and rectal cancers. These systems will enable anisotropic intensity modulation of brachytherapy dose distributions by incorporating rotating metallic shields inside brachytherapy catheters and applicators.
Designed and delivered with accurate anatomic reference, the developed systems will tailor treatments to each individual patient by treating all parts of the tumor without needlessly irradiating large regions of normal tissues surrounding the tumor. Intensity modulated brachytherapy will increase the probability of response and cure while avoiding toxicity, which will increase the quality of life of patients suffering from cancer.
Monte Carlo-based Dosimetry
Jonathan Kalinowski, M.Sc. Student
Monte Carlo method is gold standard in simulation of radiation interaction with matter and is widely used in medical imaging and radiation physics. It plays a key role in medical physics research and development of novel technology for imaging and therapy equipment. Our group develops Monte Carlo based radiation dose calculation engines and treatment planning systems for use in conventional and intensity modulated brachytherapy, as well external beam radiotherapy.
For brachytherapy applications we have developed a Monte Carlo based radiation transport package called RapidBrachyMC, coupled to dose optimization algorithms, contouring tools and a comprehensive analysis package. This toolkit is standalone and enables planning of an optimal and accurate radiation dose to the tumour while sparing healthy tissues. The complete treatment planning system is called RapidBrachyMCTPS. It can be used to validate dose distributions from clinical treatment planning systems or commercial model-based dose calculation algorithms and is also well suited to develop and validate novel combinations of radiation sources and applicators, especially those shielded with high-Z materials.
Development of a Fast and Accurate Dosimetry Toolkit for Radioembolization with Yttrium-90
Diane Alvarez, Ph.D. Student & Peter Kim, M.Sc.
The standard dosimetry for radionuclide-based cancer treatments is built on the simplistic medical internal radiation dose (MIRD) formalism that assumes a uniform radionuclide and absorbed dose distribution in the tumor. A more accurate dosimetry method that considers a heterogeneous radionuclide uptake and hence a heterogeneous dose distribution in the tumor is required. Ideally, attenuation of the radiation by heterogeneities in the patient tissues should also be taken into account. The purpose of this project is to develop and validate an image-based dosimetry software with a Monte Carlo dose calculation engine that will enable accurate and personalized dosimetry. The software considers heterogeneous radionuclide uptake and attenuation of the radiation by heterogeneities in the patient tissues.
Although the software toolkit may be applicable to many radionuclide treatments, this project focuses on a treatment called radioembolization, which uses Yttirum-90 filled resin or glass microspheres. Injected through a micro-catheter, microspheres are selectively deposited and permanently lodged within the hepatic arteries to preferentially irradiate hepatic tumors. With this software, we aim to establish a standard methodology that provides accurate dosimetry.
Treatment Plan Optimization in High Dose Rate Brachytherapy
Hossein Jafarzadeh, M.Sc. Student
Catheter Position Optimization in High Dose Rate Brachytherapy
In interstitial high dose rate brachytherapy, a highly radioactive source, usually 192Ir, is temporarily placed inside or in proximity of the tumor via thin hollow implanted catheters which are connected a machine called an afterloader. The afterloader contains a single radioactive source at the end of a wire. The source is pushed into each of the catheters, one by one under computer control and guided to the tumor site. The computer controls where along the catheter the source should pause to deliver its radiation (dwell positions) and how long it dwells at each position (dwell time). After the desired dose is delivered, the source is pulled back to the afterloader and the catheters are removed. Since the dwell times are optimized, the position of catheters has a major impact on the treatment plan quality. Efforts in optimizing the catheter positions have not been explored as extensively as the other aspects of the treatment planning workflow. This gap in knowledge motivates us to further explore this problem.
Penalty Weight Optimization in High Dose Rate Brachytherapy
Treatment plan optimization problem in high dose rate brachytherapy is formulated as a constrained optimization problem. First the dose constraints and penalty weights are determined by the clinicians, then the optimization problem is solved by linear programing. The dose constraints are usually fixed for each patient depending on the treated tumor site and the treatment planning guidelines followed. However, the clinicians select different penalty weights, leading to different optimization problems and finally adopt the one that results in the most desirable dose distribution. To remove the clinicians, influence on plan quality, reinforcement learning is explored.
Development of a Software Package for Monte Carlo-based Intravascular Brachytherapy Dosimetry
Maryam Rahbaran, B.Sc. Student
Intravascular brachytherapy is a means of treating restenosis after an angioplasty and stent insertion. Angioplasty and stent insertion can provoke an inflammatory response in the treated vessel which causes the rapid proliferation of neotintimal (scar) tissue. By eliminating neointimal tissue, intravascular brachytherapy allows treated vessels to maintain a healthy diameter. In recent years intravascular brachytherapy has seen reduced use, in favour of drug eluting stents. However, a demand for intravascular brachytherapy continues to exist in patients for whom drug eluting stents have been unsuccessful.
Beta sources are typically used in intravascular brachytherapy to reduce the need for radiation shielding in catheterization labs and to reduce the dose delivered to healthy tissues of the patient. Beta sources have high dose gradients that are affected by the presence of heterogeneities. Arterial plaques, stents, and guidewires have been shown to reduce the dose delivered to target volume from beta sources in intravascular brachytherapy. Our work allows for an understanding of the dosimetric shortcomings of commercially available intravascular brachytherapy delivery systems.
Publications
2021
Morcos, Marc; Antaki, Majd; Thibodeau-Antonacci, Alana; Kalinowski, Jonathan; Glickman, Harry; Enger, Shirin A.
RapidBrachyMCTPS: An open-source dose calculation and optimization tool for brachytherapy research Presentation
COMP, 01.06.2021.
@misc{Morcos2021c,
title = {RapidBrachyMCTPS: An open-source dose calculation and optimization tool for brachytherapy research},
author = {Marc Morcos and Majd Antaki and Alana Thibodeau-Antonacci and Jonathan Kalinowski and Harry Glickman and Shirin A. Enger},
year = {2021},
date = {2021-06-01},
howpublished = {COMP},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Morcos, Marc; Viswanathan, Akila N.; Enger, Shirin A.
In: Medical Physics, 48 (5), pp. 2604–2613, 2021, ISSN: 2473-4209.
@article{morcos_impact_2021,
title = {On the impact of absorbed dose specification, tissue heterogeneities, and applicator heterogeneities on Monte Carlo-based dosimetry of Ir-192, Se-75, and Yb-169 in conventional and intensity-modulated brachytherapy for the treatment of cervical cancer},
author = {Marc Morcos and Akila N. Viswanathan and Shirin A. Enger},
doi = {10.1002/mp.14802},
issn = {2473-4209},
year = {2021},
date = {2021-05-01},
journal = {Medical Physics},
volume = {48},
number = {5},
pages = {2604--2613},
abstract = {PURPOSE: The purpose of this study was to evaluate the impact of dose reporting schemes and tissue/applicator heterogeneities for 192 Ir-, 75 Se-, and 169 Yb-based MRI-guided conventional and intensity-modulated brachytherapy. METHODS AND MATERIALS: Treatment plans using a variety of dose reporting and tissue/applicator segmentation schemes were generated for a cohort (n = 10) of cervical cancer patients treated with 192 Ir-based Venezia brachytherapy. Dose calculations were performed using RapidBrachyMCTPS, a Geant4-based research Monte Carlo treatment planning system. Ultimately, five dose calculation scenarios were evaluated: (a) dose to water in water (Dw,w ); (b) Dw,w taking the applicator material into consideration (Dw,wApp ); (c) dose to water in medium (Dw,m ); (d and e) dose to medium in medium with mass densities assigned either nominally per structure (Dm,m (Nom) ) or voxel-by-voxel (Dm,m ).
RESULTS: Ignoring the plastic Venezia applicator (Dw,wApp ) overestimates Dm,m by up to 1% (average) with high energy source (192 Ir and 75 Se) and up to 2% with 169 Yb. Scoring dose to water (Dw,wApp or Dw,m ) generally overestimates dose and this effect increases with decreasing photon energy. Reporting dose other than Dm,m (or Dm,m Nom ) for 169 Yb-based conventional and intensity-modulated brachytherapy leads to a simultaneous overestimation (up to 4%) of CTVHR D90 and underestimation (up to 2%) of bladder D2cc due to a significant dip in the mass-energy absorption ratios at the depths of nearby targets and OARs. Using a nominal mass-density assignment per structure, rather than a CT-derived voxel-by-voxel assignment for MRI-guided brachytherapy, amounts to a dose error up to 1% for all radionuclides considered.
CONCLUSIONS: The effects of the considered dose reporting schemes trend correspondingly between conventional and intensity-modulated brachytherapy. In the absence of CT-derived mass densities, MRI-only-based dosimetry can adequately approximate Dm,m by assigning nominal mass densities to structures. Tissue and applicator heterogeneities do not significantly impact dosimetry for 192 Ir and 75 Se, but do for 169 Yb; dose reporting must be explicitly defined since Dw,m and Dw,w may overstate the dosimetric benefits.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
RESULTS: Ignoring the plastic Venezia applicator (Dw,wApp ) overestimates Dm,m by up to 1% (average) with high energy source (192 Ir and 75 Se) and up to 2% with 169 Yb. Scoring dose to water (Dw,wApp or Dw,m ) generally overestimates dose and this effect increases with decreasing photon energy. Reporting dose other than Dm,m (or Dm,m Nom ) for 169 Yb-based conventional and intensity-modulated brachytherapy leads to a simultaneous overestimation (up to 4%) of CTVHR D90 and underestimation (up to 2%) of bladder D2cc due to a significant dip in the mass-energy absorption ratios at the depths of nearby targets and OARs. Using a nominal mass-density assignment per structure, rather than a CT-derived voxel-by-voxel assignment for MRI-guided brachytherapy, amounts to a dose error up to 1% for all radionuclides considered.
CONCLUSIONS: The effects of the considered dose reporting schemes trend correspondingly between conventional and intensity-modulated brachytherapy. In the absence of CT-derived mass densities, MRI-only-based dosimetry can adequately approximate Dm,m by assigning nominal mass densities to structures. Tissue and applicator heterogeneities do not significantly impact dosimetry for 192 Ir and 75 Se, but do for 169 Yb; dose reporting must be explicitly defined since Dw,m and Dw,w may overstate the dosimetric benefits.
Morcos, Marc; Enger, Shirin A.
A novel minimally invasive IMBT delivery system for cervical cancer Presentation
JGH-Lady Davis Institute, 01.02.2021.
@misc{Morcos2021b,
title = {A novel minimally invasive IMBT delivery system for cervical cancer},
author = {Marc Morcos and Shirin A. Enger},
year = {2021},
date = {2021-02-01},
howpublished = {JGH-Lady Davis Institute},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Morcos, Marc; Antaki, Majd; Viswanathan, Akila N.; Enger, Shirin A.
A novel minimally invasive dynamic-shield, intensity-modulated brachytherapy system for the treatment of cervical cancer Journal Article
In: Medical Physics, 48 (1), pp. 71–79, 2021, ISSN: 2473-4209.
@article{morcos_novel_2021,
title = {A novel minimally invasive dynamic-shield, intensity-modulated brachytherapy system for the treatment of cervical cancer},
author = {Marc Morcos and Majd Antaki and Akila N. Viswanathan and Shirin A. Enger},
doi = {10.1002/mp.14459},
issn = {2473-4209},
year = {2021},
date = {2021-01-01},
journal = {Medical Physics},
volume = {48},
number = {1},
pages = {71--79},
abstract = {PURPOSE: To present a novel, MRI-compatible dynamicshield intensity modulated brachytherapy (IMBT) applicator and delivery system using 192 Ir, 75 Se, and 169 Yb radioisotopes for the treatment of locally advanced cervical cancer. Needle-free IMBT is a promising technique for improving target coverage and organs at risk (OAR) sparing.
METHODS AND MATERIALS: The IMBT delivery system dynamically controls the rotation of a novel tungsten shield placed inside an MRI-compatible, 6-mm wide intrauterine tandem. Using 36 cervical cancer cases, conventional intracavitary brachytherapy (IC-BT) and intracavitary/interstitial brachytherapy (IC/IS-BT) (10Ci 192 Ir) plans were compared to IMBT (10Ci 192 Ir; 11.5Ci 75 Se; 44Ci 169 Yb). All plans were generated using the Geant4-based Monte Carlo dose calculation engine, RapidBrachyMC. Treatment plans were optimized then normalized to the same high-risk clinical target volume (HR-CTV) D90 and the D2cc for bladder, rectum, and sigmoid in the research brachytherapy planning system, RapidBrachyMCTPS. Plans were renormalized until either of the three OAR reached dose limits to calculate the maximum achievable HR-CTV D90 and D98 . RESULTS: Compared to IC-BT, IMBT with either of the three radionuclides significantly improves the HR-CTV D90 and D98 by up to 5.2% ± 0.3% (P textless 0.001) and 6.7% ± 0.5% (P textless 0.001), respectively, with the largest dosimetric enhancement when using 169 Yb followed by 75 Se and then 192 Ir. Similarly, D2cc for all OAR improved with IMBT by up to 7.7% ± 0.6% (P textless 0.001). For IC/IS-BT cases, needle-free IMBT achieved clinically acceptable plans with 169 Yb-based IMBT further improving HR-CTV D98 by 1.5% ± 0.2% (P = 0.034) and decreasing sigmoid D2cc by 1.9% ± 0.4% (P = 0.048). Delivery times for IMBT are increased by a factor of 1.7, 3.3, and 2.3 for 192 Ir, 75 Se, and 169 Yb, respectively, relative to conventional 192 Ir BT.
CONCLUSIONS: Dynamic shield IMBT provides a promising alternative to conventional IC- and IC/IS-BT techniques with significant dosimetric enhancements and even greater improvements with intermediate energy radionuclides. The ability to deliver a highly conformal, OAR-sparing dose without IS needles provides a simplified method for improving the therapeutic ratio less invasively and in a less resource intensive manner.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
METHODS AND MATERIALS: The IMBT delivery system dynamically controls the rotation of a novel tungsten shield placed inside an MRI-compatible, 6-mm wide intrauterine tandem. Using 36 cervical cancer cases, conventional intracavitary brachytherapy (IC-BT) and intracavitary/interstitial brachytherapy (IC/IS-BT) (10Ci 192 Ir) plans were compared to IMBT (10Ci 192 Ir; 11.5Ci 75 Se; 44Ci 169 Yb). All plans were generated using the Geant4-based Monte Carlo dose calculation engine, RapidBrachyMC. Treatment plans were optimized then normalized to the same high-risk clinical target volume (HR-CTV) D90 and the D2cc for bladder, rectum, and sigmoid in the research brachytherapy planning system, RapidBrachyMCTPS. Plans were renormalized until either of the three OAR reached dose limits to calculate the maximum achievable HR-CTV D90 and D98 . RESULTS: Compared to IC-BT, IMBT with either of the three radionuclides significantly improves the HR-CTV D90 and D98 by up to 5.2% ± 0.3% (P textless 0.001) and 6.7% ± 0.5% (P textless 0.001), respectively, with the largest dosimetric enhancement when using 169 Yb followed by 75 Se and then 192 Ir. Similarly, D2cc for all OAR improved with IMBT by up to 7.7% ± 0.6% (P textless 0.001). For IC/IS-BT cases, needle-free IMBT achieved clinically acceptable plans with 169 Yb-based IMBT further improving HR-CTV D98 by 1.5% ± 0.2% (P = 0.034) and decreasing sigmoid D2cc by 1.9% ± 0.4% (P = 0.048). Delivery times for IMBT are increased by a factor of 1.7, 3.3, and 2.3 for 192 Ir, 75 Se, and 169 Yb, respectively, relative to conventional 192 Ir BT.
CONCLUSIONS: Dynamic shield IMBT provides a promising alternative to conventional IC- and IC/IS-BT techniques with significant dosimetric enhancements and even greater improvements with intermediate energy radionuclides. The ability to deliver a highly conformal, OAR-sparing dose without IS needles provides a simplified method for improving the therapeutic ratio less invasively and in a less resource intensive manner.
Morcos, Marc; Viswanathan, Akila N.; Enger, Shirin A.
In: Medical Physics, 48 (5), pp. 2604–2613, 2021, ISSN: 2473-4209, (_eprint: https://aapm.onlinelibrary.wiley.com/doi/pdf/10.1002/mp.14802).
@article{morcos_impact_2021b,
title = {On the impact of absorbed dose specification, tissue heterogeneities, and applicator heterogeneities on Monte Carlo-based dosimetry of Ir-192, Se-75, and Yb-169 in conventional and intensity-modulated brachytherapy for the treatment of cervical cancer},
author = {Marc Morcos and Akila N. Viswanathan and Shirin A. Enger},
url = {https://aapm.onlinelibrary.wiley.com/doi/abs/10.1002/mp.14802},
doi = {10.1002/mp.14802},
issn = {2473-4209},
year = {2021},
date = {2021-01-01},
urldate = {2021-09-08},
journal = {Medical Physics},
volume = {48},
number = {5},
pages = {2604--2613},
abstract = {Purpose The purpose of this study was to evaluate the impact of dose reporting schemes and tissue/applicator heterogeneities for 192Ir-, 75Se-, and 169Yb-based MRI-guided conventional and intensity-modulated brachytherapy. Methods and Materials Treatment plans using a variety of dose reporting and tissue/applicator segmentation schemes were generated for a cohort (n = 10) of cervical cancer patients treated with 192Ir-based Venezia brachytherapy. Dose calculations were performed using RapidBrachyMCTPS, a Geant4-based research Monte Carlo treatment planning system. Ultimately, five dose calculation scenarios were evaluated: (a) dose to water in water (Dw,w); (b) Dw,w taking the applicator material into consideration (Dw,wApp); (c) dose to water in medium (Dw,m); (d and e) dose to medium in medium with mass densities assigned either nominally per structure (Dm,m (Nom)) or voxel-by-voxel (Dm,m). Results Ignoring the plastic Venezia applicator (Dw,wApp) overestimates Dm,m by up to 1% (average) with high energy source (192Ir and 75Se) and up to 2% with 169Yb. Scoring dose to water (Dw,wApp or Dw,m) generally overestimates dose and this effect increases with decreasing photon energy. Reporting dose other than Dm,m (or Dm,m Nom) for 169Yb-based conventional and intensity-modulated brachytherapy leads to a simultaneous overestimation (up to 4%) of CTVHR D90 and underestimation (up to 2%) of bladder D2cc due to a significant dip in the mass-energy absorption ratios at the depths of nearby targets and OARs. Using a nominal mass-density assignment per structure, rather than a CT-derived voxel-by-voxel assignment for MRI-guided brachytherapy, amounts to a dose error up to 1% for all radionuclides considered. Conclusions The effects of the considered dose reporting schemes trend correspondingly between conventional and intensity-modulated brachytherapy. In the absence of CT-derived mass densities, MRI-only-based dosimetry can adequately approximate Dm,m by assigning nominal mass densities to structures. Tissue and applicator heterogeneities do not significantly impact dosimetry for 192Ir and 75Se, but do for 169Yb; dose reporting must be explicitly defined since Dw,m and Dw,w may overstate the dosimetric benefits.},
note = {_eprint: https://aapm.onlinelibrary.wiley.com/doi/pdf/10.1002/mp.14802},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Morcos, Marc; Antaki, Majd; Viswanathan, Akila N.; Enger, Shirin A.
ESTRO Newsletter, 2021.
@misc{nokey,
title = {A novel, minimally invasive, dynamic‐shield, intensity‐modulated brachytherapy system for the treatment of cervical cancer. Editors’ pick.},
author = {Marc Morcos and Majd Antaki and Akila N. Viswanathan and Shirin A. Enger},
url = {https://www.estro.org/About/Newsroom/Newsletter/Brachytheraphy/A-novel,-minimally-invasive,-dynamic%E2%80%90shield,-inten },
year = {2021},
date = {2021-01-01},
howpublished = {ESTRO Newsletter},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}
Morcos, Marc; Enger, Shirin A.
MR-guided intensity modulated brachytherapy for gynecologic cancers Presentation
McGill FMT, 01.01.2021.
@misc{Morcos2021,
title = {MR-guided intensity modulated brachytherapy for gynecologic cancers},
author = {Marc Morcos and Shirin A. Enger},
year = {2021},
date = {2021-01-01},
howpublished = {McGill FMT},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
2020
Famulari, Gabriel; Enger, Shirin A.
La curiethérapie avec modulation d’intensité par blindage dynamique pour le cancer de la prostate Presentation
Association Québécoise des Physiciens Médicaux Cliniques (AQPMC) Annual Meeting in QC, 02.11.2020.
@misc{Famulari2020b,
title = {La curiethérapie avec modulation d’intensité par blindage dynamique pour le cancer de la prostate},
author = {Gabriel Famulari and Shirin A. Enger},
year = {2020},
date = {2020-11-02},
howpublished = {Association Québécoise des Physiciens Médicaux Cliniques (AQPMC) Annual Meeting in QC},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Turgeon, Vincent; Morcos, Marc; Antaki, Majd; Enger, Shirin A.
Impact of choices in dosimetric calculation method for high dose rate brachytherapy of breast cancer Presentation
Radiotherapy and Oncology, 01.11.2020, ISSN: 0167-8140, 1879-0887.
@misc{Turgeon2020,
title = {Impact of choices in dosimetric calculation method for high dose rate brachytherapy of breast cancer},
author = {Vincent Turgeon and Marc Morcos and Majd Antaki and Shirin A. Enger},
url = {https://www.thegreenjournal.com/article/S0167-8140(21)01974-5/fulltext},
doi = {10.1016/S0167-8140(21)01974-5},
issn = {0167-8140, 1879-0887},
year = {2020},
date = {2020-11-01},
abstract = {www.thegreenjournal.com},
howpublished = {Radiotherapy and Oncology},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Rosales, Haydee M. Linares; Dupere, Justine; Medich, David C.; Beaulieu, Luc; Enger, Shirin A.
In: Medical Physics, 47 (9), pp. 4563–4573, 2020, ISSN: 2473-4209.
@article{famulari_monte_2020,
title = {Monte Carlo dosimetric characterization of a new high dose rate 169 Yb brachytherapy source and independent verification using a multipoint plastic scintillator detector},
author = {Gabriel Famulari and Haydee M. Linares Rosales and Justine Dupere and David C. Medich and Luc Beaulieu and Shirin A. Enger},
doi = {10.1002/mp.14336},
issn = {2473-4209},
year = {2020},
date = {2020-09-01},
journal = {Medical Physics},
volume = {47},
number = {9},
pages = {4563--4573},
abstract = {PURPOSE: A prototype 169 Yb source was developed in combination with a dynamic rotating platinum shield system (AIM-Brachy) to deliver intensity modulated brachytherapy (IMBT). The purpose of this study was to evaluate the dosimetric characteristics of the bare/shielded 169 Yb source using Monte Carlo (MC) simulations and perform an independent dose verification using a dosimetry platform based on a multipoint plastic scintillator detector (mPSD).
METHODS: The TG-43U1 dosimetric parameters were calculated for the source model using RapidBrachyMCTPS. Real-time dose rate measurements were performed in a water tank for both the bare/shielded source using a custom remote afterloader. For each dwell position, the dose rate was independently measured by the three scintillators (BCF-10, BCF-12, and BCF-60). For the bare source, dose rate was measured at distances up to 3 cm away from the source over a range of 7 cm along the catheter. For the shielded source, measurements were performed with the mPSD placed at 1 cm from the source at four different azimuthal angles ( 0 ∘ , 9 0 ∘ , 18 0 ∘ , and 27 0 ∘ ).
RESULTS: The dosimetric parameters were tabulated for the source model. For the bare source, differences between measured and calculated along-away dose rates were generally below 5-10%. Along the transverse axis, deviations were, on average (range), 3.3% (0.6-6.2%) for BCF-10, 1.7% (0.9-2.9%) for BCF-12, and 2.2% (0.3-4.4%) for BCF-60. The maximum dose rate reduction due to shielding at a radial distance of 1 cm was 88.8 ± 1.2%, compared to 83.5 ± 0.5% as calculated by MC.
CONCLUSIONS: The dose distribution for the bare/shielded 169 Yb source was independently verified using mPSD with good agreement in regions close to the source. The 169 Yb source coupled with the partial-shielding system is an effective technique to deliver IMBT.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
METHODS: The TG-43U1 dosimetric parameters were calculated for the source model using RapidBrachyMCTPS. Real-time dose rate measurements were performed in a water tank for both the bare/shielded source using a custom remote afterloader. For each dwell position, the dose rate was independently measured by the three scintillators (BCF-10, BCF-12, and BCF-60). For the bare source, dose rate was measured at distances up to 3 cm away from the source over a range of 7 cm along the catheter. For the shielded source, measurements were performed with the mPSD placed at 1 cm from the source at four different azimuthal angles ( 0 ∘ , 9 0 ∘ , 18 0 ∘ , and 27 0 ∘ ).
RESULTS: The dosimetric parameters were tabulated for the source model. For the bare source, differences between measured and calculated along-away dose rates were generally below 5-10%. Along the transverse axis, deviations were, on average (range), 3.3% (0.6-6.2%) for BCF-10, 1.7% (0.9-2.9%) for BCF-12, and 2.2% (0.3-4.4%) for BCF-60. The maximum dose rate reduction due to shielding at a radial distance of 1 cm was 88.8 ± 1.2%, compared to 83.5 ± 0.5% as calculated by MC.
CONCLUSIONS: The dose distribution for the bare/shielded 169 Yb source was independently verified using mPSD with good agreement in regions close to the source. The 169 Yb source coupled with the partial-shielding system is an effective technique to deliver IMBT.
Famulari, Gabriel; Enger, Shirin A.
AIM-Brachy: a novel intensity modulated brachytherapy (IMBT) delivery system for prostate cancer. Winner of the 2019 Jean Pouliot Prize for best paper published in 2019 awarded by Association Québécoise des Physicien(ne) Médicaux Cliniques. Award
from Association Québécoise des Physicien(ne) Médicaux Cliniques in 2020.
@award{Famulari2020,
title = {AIM-Brachy: a novel intensity modulated brachytherapy (IMBT) delivery system for prostate cancer. Winner of the 2019 Jean Pouliot Prize for best paper published in 2019 awarded by Association Québécoise des Physicien(ne) Médicaux Cliniques.},
author = {Gabriel Famulari and Shirin A. Enger},
year = {2020},
date = {2020-07-01},
urldate = {2020-07-01},
organization = {Association Québécoise des Physicien(ne) Médicaux Cliniques},
howpublished = {Med. Phys., 47(3):859-868 (2020)},
keywords = {},
pubstate = {published},
tppubtype = {award}
}
Famulari, Gabriel; Enger, Shirin A.
Monte Carlo dosimetry of a custom-made 169Yb source for intensity modulated brachytherapy Presentation
MCMA, 20.06.2020.
@misc{Famulari2020c,
title = {Monte Carlo dosimetry of a custom-made 169Yb source for intensity modulated brachytherapy},
author = {Gabriel Famulari and Shirin A. Enger},
year = {2020},
date = {2020-06-20},
howpublished = {MCMA},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Morcos, Marc; Enger, Shirin A.
Monte Carlo Dosimetry Study of Novel Rotating MRI-Compatible Shielded Tandems for Intensity Modulated Cervix Brachytherapy Presentation
MCMA, 20.06.2020.
@misc{Morcos2020,
title = {Monte Carlo Dosimetry Study of Novel Rotating MRI-Compatible Shielded Tandems for Intensity Modulated Cervix Brachytherapy},
author = {Marc Morcos and Shirin A. Enger},
year = {2020},
date = {2020-06-20},
howpublished = {MCMA},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Alfieri, Joanne; Duclos, Marie; Vuong, Té; Enger, Shirin A.
Can intermediate-energy sources lead to elevated bone doses for prostate and head & neck high-dose-rate brachytherapy? Journal Article
In: Brachytherapy, 19 (2), pp. 255–263, 2020, ISSN: 1873-1449.
@article{famulari_can_2020,
title = {Can intermediate-energy sources lead to elevated bone doses for prostate and head & neck high-dose-rate brachytherapy?},
author = {Gabriel Famulari and Joanne Alfieri and Marie Duclos and Té Vuong and Shirin A. Enger},
doi = {10.1016/j.brachy.2019.12.004},
issn = {1873-1449},
year = {2020},
date = {2020-04-01},
journal = {Brachytherapy},
volume = {19},
number = {2},
pages = {255--263},
abstract = {PURPOSE: Several radionuclides with high (60Co, 75Se) and intermediate (169Yb, 153Gd) energies have been investigated as alternatives to 192Ir for high-dose-rate brachytherapy. The purpose of this study was to evaluate the impact of tissue heterogeneities for these five high- to intermediate-energy sources in prostate and head & neck brachytherapy. METHODS AND MATERIALS: Treatment plans were generated for a cohort of prostate (n = 10) and oral tongue (n = 10) patients. Dose calculations were performed using RapidBrachyMCTPS, an in-house Geant4-based Monte Carlo treatment planning system. Treatment plans were simulated using 60Co, 192Ir, 75Se, 169Yb, and 153Gd as the active core of the microSelectron v2 source. Two dose calculation scenarios were presented: (1) dose to water in water (Dw,w), and (2) dose to medium in medium (Dm,m).
RESULTS: Dw,w overestimates planning target volume coverage compared with Dm,m, regardless of photon energy. The average planning target volume D90 reduction was ∼1% for high-energy sources, whereas larger differences were observed for intermediate-energy sources (1%-2% for prostate and 4%-7% for oral tongue). Dose differences were not clinically relevant (textless5%) for soft tissues in general. Going from Dw,w to Dm,m, bone doses were increased two- to three-fold for 169Yb and four- to five-fold for 153Gd, whereas the ratio was close to ∼1 for high-energy sources.
CONCLUSIONS: Dw,w underestimates the dose to bones and, to a lesser extent, overestimates the dose to soft tissues for radionuclides with average energies lower than 192Ir. Further studies regarding bone toxicities are needed before intermediate-energy sources can be adopted in cases where bones are in close vicinity to the tumor.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
RESULTS: Dw,w overestimates planning target volume coverage compared with Dm,m, regardless of photon energy. The average planning target volume D90 reduction was ∼1% for high-energy sources, whereas larger differences were observed for intermediate-energy sources (1%-2% for prostate and 4%-7% for oral tongue). Dose differences were not clinically relevant (textless5%) for soft tissues in general. Going from Dw,w to Dm,m, bone doses were increased two- to three-fold for 169Yb and four- to five-fold for 153Gd, whereas the ratio was close to ∼1 for high-energy sources.
CONCLUSIONS: Dw,w underestimates the dose to bones and, to a lesser extent, overestimates the dose to soft tissues for radionuclides with average energies lower than 192Ir. Further studies regarding bone toxicities are needed before intermediate-energy sources can be adopted in cases where bones are in close vicinity to the tumor.
Famulari, Gabriel; Duclos, Marie; Enger, Shirin A.
A novel 169 Yb-based dynamic-shield intensity modulated brachytherapy delivery system for prostate cancer Journal Article
In: Medical Physics, 47 (3), pp. 859–868, 2020, ISSN: 2473-4209.
@article{famulari_novel_2020,
title = {A novel 169 Yb-based dynamic-shield intensity modulated brachytherapy delivery system for prostate cancer},
author = {Gabriel Famulari and Marie Duclos and Shirin A. Enger},
doi = {10.1002/mp.13959},
issn = {2473-4209},
year = {2020},
date = {2020-03-01},
journal = {Medical Physics},
volume = {47},
number = {3},
pages = {859--868},
abstract = {PURPOSE: Intensity modulated brachytherapy (IMBT) is a novel high dose rate brachytherapy (HDR BT) technique which incorporates static or dynamic shielding to increase tumor coverage and/or spare healthy tissues. The purpose of this study is to present a novel delivery system (AIM-Brachy) design that can enable dynamic-shield IMBT for prostate cancer.
METHODS: The AIM-Brachy system dynamically controls the rotation of platinum shields, placed within interstitial catheters, which partially collimate the radiation emitted from an 169 Yb source. Conventional HDR BT (10 Ci 192 Ir) and IMBT (18 Ci 169 Yb) plans were generated for 12 patients using an in-house column generation-based optimizer, coupled to a Geant4-based dose calculation engine, RapidBrachyMC. Treatment plans were normalized to match the same PTV D90 coverage as the clinical plan. Intershield attenuation effects were taken into account. A sensitivity analysis was performed to evaluate the dosimetric impact of systematic longitudinal source positioning errors ( ± 1 mm, ± 2 mm, and ± 3 mm) and rotational errors ( ± 5 ∘ , ± 10 ∘ , and ± 15 ∘ ) on clinically relevant parameters (PTV D90 and urethra D10 ).
RESULTS: The platinum shield reduced the dose rate on the shielded side at 1 cm to 18.1% of the dose rate on the unshielded side. For equal PTV D90 coverage, the urethral D10 was reduced by 13.3% ± 4.7%, without change to other plan quality indices (PTV V100 , V150, V200 , bladder V75 , rectum V75 , HI, COIN). Delivery times for HDR BT and IMBT were 9.2 ± 1.6 min and 18.6 ± 4.0 min, respectively. In general, the PTV D90 was more sensitive to source positioning errors than rotational errors, while the urethral D10 was more sensitive to rotational errors than source positioning errors. For a typical range of positioning errors ( ± 1 mm, ± 5 ∘ ), the overall tolerance was textless2%.
CONCLUSIONS: The AIM-Brachy system was proposed to deliver dynamic-shield IMBT for prostate cancer with the potential to create a low dose tunnel within the urethra. The urethra-sparing properties are desirable to minimize the occurrence and severity of urethral strictures or, alternatively, to provide a method for dose escalation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
METHODS: The AIM-Brachy system dynamically controls the rotation of platinum shields, placed within interstitial catheters, which partially collimate the radiation emitted from an 169 Yb source. Conventional HDR BT (10 Ci 192 Ir) and IMBT (18 Ci 169 Yb) plans were generated for 12 patients using an in-house column generation-based optimizer, coupled to a Geant4-based dose calculation engine, RapidBrachyMC. Treatment plans were normalized to match the same PTV D90 coverage as the clinical plan. Intershield attenuation effects were taken into account. A sensitivity analysis was performed to evaluate the dosimetric impact of systematic longitudinal source positioning errors ( ± 1 mm, ± 2 mm, and ± 3 mm) and rotational errors ( ± 5 ∘ , ± 10 ∘ , and ± 15 ∘ ) on clinically relevant parameters (PTV D90 and urethra D10 ).
RESULTS: The platinum shield reduced the dose rate on the shielded side at 1 cm to 18.1% of the dose rate on the unshielded side. For equal PTV D90 coverage, the urethral D10 was reduced by 13.3% ± 4.7%, without change to other plan quality indices (PTV V100 , V150, V200 , bladder V75 , rectum V75 , HI, COIN). Delivery times for HDR BT and IMBT were 9.2 ± 1.6 min and 18.6 ± 4.0 min, respectively. In general, the PTV D90 was more sensitive to source positioning errors than rotational errors, while the urethral D10 was more sensitive to rotational errors than source positioning errors. For a typical range of positioning errors ( ± 1 mm, ± 5 ∘ ), the overall tolerance was textless2%.
CONCLUSIONS: The AIM-Brachy system was proposed to deliver dynamic-shield IMBT for prostate cancer with the potential to create a low dose tunnel within the urethra. The urethra-sparing properties are desirable to minimize the occurrence and severity of urethral strictures or, alternatively, to provide a method for dose escalation.
Famulari, Gabriel; Alfieri, Joanne; Duclos, Marie; Vuong, Té; Enger, Shirin A.
Can intermediate-energy sources lead to elevated bone doses for prostate and head & neck high-dose-rate brachytherapy? Journal Article
In: Brachytherapy, 19 (2), pp. 255–263, 2020, ISSN: 1538-4721.
@article{famulari_can_2020b,
title = {Can intermediate-energy sources lead to elevated bone doses for prostate and head & neck high-dose-rate brachytherapy?},
author = {Gabriel Famulari and Joanne Alfieri and Marie Duclos and Té Vuong and Shirin A. Enger},
url = {https://www.sciencedirect.com/science/article/pii/S1538472119306531},
doi = {10.1016/j.brachy.2019.12.004},
issn = {1538-4721},
year = {2020},
date = {2020-03-01},
urldate = {2021-09-08},
journal = {Brachytherapy},
volume = {19},
number = {2},
pages = {255--263},
abstract = {Purpose
Several radionuclides with high (60Co, 75Se) and intermediate (169Yb, 153Gd) energies have been investigated as alternatives to 192Ir for high-dose-rate brachytherapy. The purpose of this study was to evaluate the impact of tissue heterogeneities for these five high- to intermediate-energy sources in prostate and head & neck brachytherapy.
Methods and Materials Treatment plans were generated for a cohort of prostate (n = 10) and oral tongue (n = 10) patients. Dose calculations were performed using RapidBrachyMCTPS, an in-house Geant4-based Monte Carlo treatment planning system. Treatment plans were simulated using 60Co, 192Ir, 75Se, 169Yb, and 153Gd as the active core of the microSelectron v2 source. Two dose calculation scenarios were presented: (1) dose to water in water (Dw,w), and (2) dose to medium in medium (Dm,m).
Results
Dw,w overestimates planning target volume coverage compared with Dm,m, regardless of photon energy. The average planning target volume D90 reduction was ∼1% for high-energy sources, whereas larger differences were observed for intermediate-energy sources (1%–2% for prostate and 4%–7% for oral tongue). Dose differences were not clinically relevant (textless5%) for soft tissues in general. Going from Dw,w to Dm,m, bone doses were increased two- to three-fold for 169Yb and four- to five-fold for 153Gd, whereas the ratio was close to ∼1 for high-energy sources.
Conclusions
Dw,w underestimates the dose to bones and, to a lesser extent, overestimates the dose to soft tissues for radionuclides with average energies lower than 192Ir. Further studies regarding bone toxicities are needed before intermediate-energy sources can be adopted in cases where bones are in close vicinity to the tumor.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Several radionuclides with high (60Co, 75Se) and intermediate (169Yb, 153Gd) energies have been investigated as alternatives to 192Ir for high-dose-rate brachytherapy. The purpose of this study was to evaluate the impact of tissue heterogeneities for these five high- to intermediate-energy sources in prostate and head & neck brachytherapy.
Methods and Materials Treatment plans were generated for a cohort of prostate (n = 10) and oral tongue (n = 10) patients. Dose calculations were performed using RapidBrachyMCTPS, an in-house Geant4-based Monte Carlo treatment planning system. Treatment plans were simulated using 60Co, 192Ir, 75Se, 169Yb, and 153Gd as the active core of the microSelectron v2 source. Two dose calculation scenarios were presented: (1) dose to water in water (Dw,w), and (2) dose to medium in medium (Dm,m).
Results
Dw,w overestimates planning target volume coverage compared with Dm,m, regardless of photon energy. The average planning target volume D90 reduction was ∼1% for high-energy sources, whereas larger differences were observed for intermediate-energy sources (1%–2% for prostate and 4%–7% for oral tongue). Dose differences were not clinically relevant (textless5%) for soft tissues in general. Going from Dw,w to Dm,m, bone doses were increased two- to three-fold for 169Yb and four- to five-fold for 153Gd, whereas the ratio was close to ∼1 for high-energy sources.
Conclusions
Dw,w underestimates the dose to bones and, to a lesser extent, overestimates the dose to soft tissues for radionuclides with average energies lower than 192Ir. Further studies regarding bone toxicities are needed before intermediate-energy sources can be adopted in cases where bones are in close vicinity to the tumor.
Morcos, Marc; Enger, Shirin A.
Monte Carlo dosimetry study of novel rotating MRI-compatible shielded tandems for intensity modulated cervix brachytherapy Journal Article
In: Physica medica: PM: an international journal devoted to the applications of physics to medicine and biology: official journal of the Italian Association of Biomedical Physics (AIFB), 71 , pp. 178–184, 2020, ISSN: 1724-191X.
@article{morcos_monte_2020,
title = {Monte Carlo dosimetry study of novel rotating MRI-compatible shielded tandems for intensity modulated cervix brachytherapy},
author = {Marc Morcos and Shirin A. Enger},
doi = {10.1016/j.ejmp.2020.02.014},
issn = {1724-191X},
year = {2020},
date = {2020-03-01},
journal = {Physica medica: PM: an international journal devoted to the applications of physics to medicine and biology: official journal of the Italian Association of Biomedical Physics (AIFB)},
volume = {71},
pages = {178--184},
abstract = {PURPOSE: Intensity modulated brachytherapy (IMBT) with rotating metal shields enables dose modulation that can better conform to the tumor while reducing OAR doses. In this work, we investigate novel rotating shields, compatible with MRI-compatible tandems used for cervix brachytherapy. Three unique shields were evaluated using the traditional 192Ir source. Additionally, 75Se and 169Yb isotopes were investigated as alternative sources.
METHODS: Three different IMBT shields were modeled and simulated in RapidBrachyMCTPS. Each tungsten shield was designed to fit inside a 6 mm-wide MRI-compatible tandem. The active core of the source was replaced with 192Ir, 75Se and 169Yb. Transmission factors (TFs) were calculated and defined as the dose ratio at 1 cm on opposite sides of the shielded tandem on the transverse plane. Polar and azimuthal anisotropy plots were extracted from simulations. Dose homogeneities V200%V100% were calculated for all radionuclide-shield combinations.
RESULTS: TFs are favorable for IMBT and ranged between 12.9% and 32.2% for 192Ir, 4.0%-16.1% for 75Se and 1.2-6.4% for 169Yb for all shield designs. Average beam-widths in the polar and azimuthal directions were reduced to the range of 42°-112° and 27°-107°, respectively, for all shield-radionuclide combinations. Dose homogeneities for all the radionuclide-shield combinations were within 12% of the non-IMBT tandem.
CONCLUSIONS: This study has quantitatively assessed the influence of various rotating cervical cancer-specific IMBT tandem shields on dosimetry. The dynamic single-channel shields and narrow beam-widths in the polar and azimuthal direction give rise to highly anisotropic distributions. Intermediate-to-high energy radionuclides, 75Se and 169Yb substantially improve the modulation capacity of IMBT and pave the way for treating large and complex cervical cancer without interstitial needle implantation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
METHODS: Three different IMBT shields were modeled and simulated in RapidBrachyMCTPS. Each tungsten shield was designed to fit inside a 6 mm-wide MRI-compatible tandem. The active core of the source was replaced with 192Ir, 75Se and 169Yb. Transmission factors (TFs) were calculated and defined as the dose ratio at 1 cm on opposite sides of the shielded tandem on the transverse plane. Polar and azimuthal anisotropy plots were extracted from simulations. Dose homogeneities V200%V100% were calculated for all radionuclide-shield combinations.
RESULTS: TFs are favorable for IMBT and ranged between 12.9% and 32.2% for 192Ir, 4.0%-16.1% for 75Se and 1.2-6.4% for 169Yb for all shield designs. Average beam-widths in the polar and azimuthal directions were reduced to the range of 42°-112° and 27°-107°, respectively, for all shield-radionuclide combinations. Dose homogeneities for all the radionuclide-shield combinations were within 12% of the non-IMBT tandem.
CONCLUSIONS: This study has quantitatively assessed the influence of various rotating cervical cancer-specific IMBT tandem shields on dosimetry. The dynamic single-channel shields and narrow beam-widths in the polar and azimuthal direction give rise to highly anisotropic distributions. Intermediate-to-high energy radionuclides, 75Se and 169Yb substantially improve the modulation capacity of IMBT and pave the way for treating large and complex cervical cancer without interstitial needle implantation.
Famulari, Gabriel; Rosales, Haydee M. Linares; Dupere, Justine; Medich, David C.; Beaulieu, Luc; Enger, Shirin A.
In: Medical Physics, 47 (9), pp. 4563–4573, 2020, ISSN: 2473-4209, (_eprint: https://aapm.onlinelibrary.wiley.com/doi/pdf/10.1002/mp.14336).
@article{famulari_monte_2020b,
title = {Monte Carlo dosimetric characterization of a new high dose rate Yb brachytherapy source and independent verification using a multipoint plastic scintillator detector},
author = {Gabriel Famulari and Haydee M. Linares Rosales and Justine Dupere and David C. Medich and Luc Beaulieu and Shirin A. Enger},
url = {https://aapm.onlinelibrary.wiley.com/doi/abs/10.1002/mp.14336},
doi = {10.1002/mp.14336},
issn = {2473-4209},
year = {2020},
date = {2020-01-01},
urldate = {2021-09-08},
journal = {Medical Physics},
volume = {47},
number = {9},
pages = {4563--4573},
abstract = {Purpose A prototype Yb source was developed in combination with a dynamic rotating platinum shield system (AIM-Brachy) to deliver intensity modulated brachytherapy (IMBT). The purpose of this study was to evaluate the dosimetric characteristics of the bare/shielded Yb source using Monte Carlo (MC) simulations and perform an independent dose verification using a dosimetry platform based on a multipoint plastic scintillator detector (mPSD). Methods The TG-43U1 dosimetric parameters were calculated for the source model using RapidBrachyMCTPS. Real-time dose rate measurements were performed in a water tank for both the bare/shielded source using a custom remote afterloader. For each dwell position, the dose rate was independently measured by the three scintillators (BCF-10, BCF-12, and BCF-60). For the bare source, dose rate was measured at distances up to 3 cm away from the source over a range of 7 cm along the catheter. For the shielded source, measurements were performed with the mPSD placed at 1 cm from the source at four different azimuthal angles ( , 9 , 18 , and 27 ). Results The dosimetric parameters were tabulated for the source model. For the bare source, differences between measured and calculated along-away dose rates were generally below 5–10%. Along the transverse axis, deviations were, on average (range), 3.3% (0.6–6.2%) for BCF-10, 1.7% (0.9–2.9%) for BCF-12, and 2.2% (0.3–4.4%) for BCF-60. The maximum dose rate reduction due to shielding at a radial distance of 1 cm was 88.8 ± 1.2%, compared to 83.5 ± 0.5% as calculated by MC. Conclusions The dose distribution for the bare/shielded Yb source was independently verified using mPSD with good agreement in regions close to the source. The Yb source coupled with the partial-shielding system is an effective technique to deliver IMBT.},
note = {_eprint: https://aapm.onlinelibrary.wiley.com/doi/pdf/10.1002/mp.14336},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Famulari, Gabriel; Duclos, Marie; Enger, Shirin A.
A novel 169Yb-based dynamic-shield intensity modulated brachytherapy delivery system for prostate cancer Journal Article
In: Medical Physics, 47 (3), pp. 859–868, 2020, ISSN: 2473-4209, (_eprint: https://aapm.onlinelibrary.wiley.com/doi/pdf/10.1002/mp.13959).
@article{famulari_novel_2020b,
title = {A novel 169Yb-based dynamic-shield intensity modulated brachytherapy delivery system for prostate cancer},
author = {Gabriel Famulari and Marie Duclos and Shirin A. Enger},
url = {https://aapm.onlinelibrary.wiley.com/doi/abs/10.1002/mp.13959},
doi = {10.1002/mp.13959},
issn = {2473-4209},
year = {2020},
date = {2020-01-01},
urldate = {2021-09-08},
journal = {Medical Physics},
volume = {47},
number = {3},
pages = {859--868},
abstract = {Purpose Intensity modulated brachytherapy (IMBT) is a novel high dose rate brachytherapy (HDR BT) technique which incorporates static or dynamic shielding to increase tumor coverage and/or spare healthy tissues. The purpose of this study is to present a novel delivery system (AIM-Brachy) design that can enable dynamic-shield IMBT for prostate cancer. Methods The AIM-Brachy system dynamically controls the rotation of platinum shields, placed within interstitial catheters, which partially collimate the radiation emitted from an 169Yb source. Conventional HDR BT (10 Ci 192Ir) and IMBT (18 Ci 169Yb) plans were generated for 12 patients using an in-house column generation-based optimizer, coupled to a Geant4-based dose calculation engine, RapidBrachyMC. Treatment plans were normalized to match the same PTV D90 coverage as the clinical plan. Intershield attenuation effects were taken into account. A sensitivity analysis was performed to evaluate the dosimetric impact of systematic longitudinal source positioning errors (1 mm, 2 mm, and 3 mm) and rotational errors (5, 10 and 15) on clinically relevant parameters (PTV D90 and urethra D10). Results The platinum shield reduced the dose rate on the shielded side at 1 cm to 18.1% of the dose rate on the unshielded side. For equal PTV D90 coverage, the urethral D10 was reduced by 13.3% 4.7%, without change to other plan quality indices (PTV V100, V150, V200, bladder V75, rectum V75, HI, COIN). Delivery times for HDR BT and IMBT were 9.2 ± 1.6 min and 18.6 ± 4.0 min, respectively. In general, the PTV D90 was more sensitive to source positioning errors than rotational errors, while the urethral D10 was more sensitive to rotational errors than source positioning errors. For a typical range of positioning errors (1 mm, 5), the overall tolerance was textless2%. Conclusions The AIM-Brachy system was proposed to deliver dynamic-shield IMBT for prostate cancer with the potential to create a low dose tunnel within the urethra. The urethra-sparing properties are desirable to minimize the occurrence and severity of urethral strictures or, alternatively, to provide a method for dose escalation.},
note = {_eprint: https://aapm.onlinelibrary.wiley.com/doi/pdf/10.1002/mp.13959},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
2019
Shoemaker, Tristan; Vuong, Té; Glickman, Harry; Kaifi, Samar; Famulari, Gabriel; Enger, Shirin A.
Dosimetric Considerations for Ytterbium-169, Selenium-75, and Iridium-192 Radioisotopes in High-Dose-Rate Endorectal Brachytherapy Journal Article
In: International Journal of Radiation Oncology, Biology, Physics, 105 (4), pp. 875–883, 2019, ISSN: 1879-355X.
@article{shoemaker_dosimetric_2019,
title = {Dosimetric Considerations for Ytterbium-169, Selenium-75, and Iridium-192 Radioisotopes in High-Dose-Rate Endorectal Brachytherapy},
author = {Tristan Shoemaker and Té Vuong and Harry Glickman and Samar Kaifi and Gabriel Famulari and Shirin A. Enger},
doi = {10.1016/j.ijrobp.2019.07.003},
issn = {1879-355X},
year = {2019},
date = {2019-11-01},
journal = {International Journal of Radiation Oncology, Biology, Physics},
volume = {105},
number = {4},
pages = {875--883},
abstract = {PURPOSE: To investigate differences between prescribed and postimplant calculated dose in 192Ir high-dose-rate endorectal brachytherapy (HDR-EBT) by evaluating dose to clinical target volume (CTV) and organs at risk (OARs) calculated with a Monte Carlo-based dose calculation software, RapidBrachyMC. In addition, dose coverage, conformity, and homogeneity were compared among the radionuclides 192Ir, 75Se, and 169Yb for use in HDR-EBT.
METHODS AND MATERIALS: Postimplant dosimetry was evaluated using 23 computed tomography (CT) images from patients treated with HDR-EBT using the 192Ir microSelectron v2 (Elekta AB, Stockholm, Sweden) source and the Intracavitary Mold Applicator Set (Elekta AB, Stockholm, Sweden), which is a flexible applicator capable of fitting a tungsten rod for OAR shielding. Four tissue segmentation schemes were evaluated: (1) TG-43 formalism, (2) materials and nominal densities assigned to contours of foreign objects, (3) materials and nominal densities assigned to contoured organs in addition to foreign objects, and (4) materials specified as in (3) but with voxel mass densities derived from CT Hounsfield units. Clinical plans optimized for 192Ir were used, with the results for 75Se and 169Yb normalized to the D90 of the 192Ir clinical plan. RESULTS: In comparison to segmentation scheme 4, TG-43-based dosimetry overestimates CTV D90 by 6% (P = .00003), rectum D50 by 24% (P = .00003), and pelvic bone D50 by 5% (P = .00003) for 192Ir. For 169Yb, CTV D90 is overestimated by 17% (P = .00003) and rectum D50 by 39% (P = .00003), and pelvic bone D50 is significantly underestimated by 27% (P = .007). Postimplant dosimetry calculations also showed that a 169Yb source would give 20% (P = .00003) lower rectum V60 and 17% (P = .00008) lower rectum D50.
CONCLUSIONS: Ignoring high-Z materials in dose calculation contributes to inaccuracies that may lead to suboptimal dose optimization and disagreement between prescribed and calculated dose. This is especially important for low-energy radionuclides. Our results also show that with future magnetic resonance imaging-based treatment planning, loss of CT density data will only affect calculated dose in nonbone OARs by 2% or less and bone OARs by 13% or less across all sources if material composition and nominal mass densities are correctly assigned.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
METHODS AND MATERIALS: Postimplant dosimetry was evaluated using 23 computed tomography (CT) images from patients treated with HDR-EBT using the 192Ir microSelectron v2 (Elekta AB, Stockholm, Sweden) source and the Intracavitary Mold Applicator Set (Elekta AB, Stockholm, Sweden), which is a flexible applicator capable of fitting a tungsten rod for OAR shielding. Four tissue segmentation schemes were evaluated: (1) TG-43 formalism, (2) materials and nominal densities assigned to contours of foreign objects, (3) materials and nominal densities assigned to contoured organs in addition to foreign objects, and (4) materials specified as in (3) but with voxel mass densities derived from CT Hounsfield units. Clinical plans optimized for 192Ir were used, with the results for 75Se and 169Yb normalized to the D90 of the 192Ir clinical plan. RESULTS: In comparison to segmentation scheme 4, TG-43-based dosimetry overestimates CTV D90 by 6% (P = .00003), rectum D50 by 24% (P = .00003), and pelvic bone D50 by 5% (P = .00003) for 192Ir. For 169Yb, CTV D90 is overestimated by 17% (P = .00003) and rectum D50 by 39% (P = .00003), and pelvic bone D50 is significantly underestimated by 27% (P = .007). Postimplant dosimetry calculations also showed that a 169Yb source would give 20% (P = .00003) lower rectum V60 and 17% (P = .00008) lower rectum D50.
CONCLUSIONS: Ignoring high-Z materials in dose calculation contributes to inaccuracies that may lead to suboptimal dose optimization and disagreement between prescribed and calculated dose. This is especially important for low-energy radionuclides. Our results also show that with future magnetic resonance imaging-based treatment planning, loss of CT density data will only affect calculated dose in nonbone OARs by 2% or less and bone OARs by 13% or less across all sources if material composition and nominal mass densities are correctly assigned.
Famulari, Gabriel; Enger, Shirin A.
Evaluation of the intershield attenuation effect for a new intensity modulated brachytherapy system for prostate cancer Presentation
American Association of Physicists in Medicine (AAPM) 61st Annual Meeting, 18.07.2019.
@misc{Famulari2019c,
title = { Evaluation of the intershield attenuation effect for a new intensity modulated brachytherapy system for prostate cancer},
author = {Gabriel Famulari and Shirin A. Enger},
year = {2019},
date = {2019-07-18},
howpublished = {American Association of Physicists in Medicine (AAPM) 61st Annual Meeting},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Enger, Shirin A.
Dosimetric characterization of a new 169Yb source for high dose rate brachytherapy Presentation
American Brachytherapy Society (ABS) Annual Meeting, 08.06.2019.
@misc{Famulari2019d,
title = {Dosimetric characterization of a new 169Yb source for high dose rate brachytherapy},
author = {Gabriel Famulari and Shirin A. Enger},
year = {2019},
date = {2019-06-08},
howpublished = {American Brachytherapy Society (ABS) Annual Meeting},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Morcos, Marc; Enger, Shirin A.
MR-Compatible Intensity Modulated Brachytherapy Applicator for Cervical Cancer Presentation
American Brachytherapy Society (ABS) Annual Meeting, 08.06.2019.
@misc{Morcos2019,
title = {MR-Compatible Intensity Modulated Brachytherapy Applicator for Cervical Cancer},
author = {Marc Morcos and Shirin A. Enger},
year = {2019},
date = {2019-06-08},
howpublished = {American Brachytherapy Society (ABS) Annual Meeting},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Enger, Shirin A.
Urethra sparing with intensity modulated brachytherapy for prostate cancer Presentation
Curietherapies, 17.05.2019.
@misc{Famulari2019e,
title = {Urethra sparing with intensity modulated brachytherapy for prostate cancer},
author = {Gabriel Famulari and Shirin A. Enger},
year = {2019},
date = {2019-05-17},
howpublished = {Curietherapies},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Morcos, Marc; Enger, Shirin A.
MR-Compatible Intensity Modulated Brachytherapy for the Treatment of Locally Advanced Cervical Cancer Presentation
Curietherapies, 17.05.2019.
@misc{Morcos2019b,
title = {MR-Compatible Intensity Modulated Brachytherapy for the Treatment of Locally Advanced Cervical Cancer},
author = {Marc Morcos and Shirin A. Enger},
year = {2019},
date = {2019-05-17},
howpublished = {Curietherapies},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Enger, Shirin A.
Intensity modulated brachytherapy for prostate cancer: plan quality, robustness and delivery time Presentation
Radiotherapy and Oncology, 01.04.2019, ISSN: 0167-8140, 1879-0887.
@misc{Famulari2019f,
title = {Intensity modulated brachytherapy for prostate cancer: plan quality, robustness and delivery time},
author = {Gabriel Famulari and Shirin A. Enger},
url = {https://www.thegreenjournal.com/article/S0167-8140(19)30817-5/fulltext},
doi = {10.1016/S0167-8140(19)30817-5},
issn = {0167-8140, 1879-0887},
year = {2019},
date = {2019-04-01},
abstract = {www.thegreenjournal.com},
howpublished = {Radiotherapy and Oncology},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Pater, Piotr; Enger, Shirin A.
Microdosimetry calculations for monoenergetic electrons using Geant4-DNA combined with a weighted track sampling algorithm Presentation
Physica Medica, 01.01.2019.
@misc{Famulari2019b,
title = {Microdosimetry calculations for monoenergetic electrons using Geant4-DNA combined with a weighted track sampling algorithm},
author = {Gabriel Famulari and Piotr Pater and Shirin A. Enger},
year = {2019},
date = {2019-01-01},
howpublished = {Physica Medica},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Enger, Shirin A.
Young Investigator Competition Award - Urethra-Sparing with Intensity Modulated Brachytherapy for Prostate Cancer Award
from in 2019.
@award{Famulari2019,
title = {Young Investigator Competition Award - Urethra-Sparing with Intensity Modulated Brachytherapy for Prostate Cancer},
author = {Gabriel Famulari and Shirin A. Enger},
year = {2019},
date = {2019-01-01},
urldate = {2019-01-01},
howpublished = {Curietherapies 2019},
keywords = {},
pubstate = {published},
tppubtype = {award}
}
2018
Famulari, Gabriel; Renaud, Marc-André; Poole, Christopher M.; Evans, Michael D. C.; Seuntjens, Jan; Enger, Shirin A.
RapidBrachyMCTPS: a Monte Carlo-based treatment planning system for brachytherapy applications Journal Article
In: Physics in Medicine and Biology, 63 (17), pp. 175007, 2018, ISSN: 1361-6560.
@article{famulari_rapidbrachymctps_2018,
title = {RapidBrachyMCTPS: a Monte Carlo-based treatment planning system for brachytherapy applications},
author = {Gabriel Famulari and Marc-André Renaud and Christopher M. Poole and Michael D. C. Evans and Jan Seuntjens and Shirin A. Enger},
doi = {10.1088/1361-6560/aad97a},
issn = {1361-6560},
year = {2018},
date = {2018-08-01},
journal = {Physics in Medicine and Biology},
volume = {63},
number = {17},
pages = {175007},
abstract = {Despite being considered the gold standard for brachytherapy dosimetry, Monte Carlo (MC) has yet to be implemented into a software for brachytherapy treatment planning. The purpose of this work is to present RapidBrachyMCTPS, a novel treatment planning system (TPS) for brachytherapy applications equipped with a graphical user interface (GUI), optimization tools and a Geant4-based MC dose calculation engine, RapidBrachyMC. Brachytherapy sources and applicators were implemented in RapidBrachyMC and made available to the user via a source and applicator library in the GUI. To benchmark RapidBrachyMC, TG-43 parameters were calculated for the microSelectron v2 (192Ir) and SelectSeed (125I) source models and were compared against previously validated MC brachytherapy codes. The performance of RapidBrachyMC was evaluated for a prostate high dose rate case. To assess the accuracy of RapidBrachyMC in a heterogeneous setup, dose distributions with a cylindrical shielded/unshielded applicator were validated against film measurements in a Solid WaterTM phantom. TG-43 parameters calculated using RapidBrachyMC generally agreed within 1%-2% of the results obtained in previously published work. For the prostate case, clinical dosimetric indices showed general agreement with Oncentra TPS within 1%. Simulation times were on the order of minutes on a single core to achieve uncertainties below 2% in voxels within the prostate. The calculation time was decreased further using the multithreading features of Geant4. In the comparison between MC-calculated and film-measured dose distributions, at least 95% of points passed the 3%/3 mm gamma index criteria in all but one case. RapidBrachyMCTPS can be used as a post-implant dosimetry toolkit, as well as for MC-based brachytherapy treatment planning. This software is especially well suited for the development of new source and applicator models.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Famulari, Gabriel; Enger, Shirin A.
AIMBrachy, A Novel Radiation Delivery System Presentation
The Cancer Research Program Research day at RI-MUHC, 22.05.2018.
@misc{Famulari2018d,
title = {AIMBrachy, A Novel Radiation Delivery System},
author = {Gabriel Famulari and Shirin A. Enger},
year = {2018},
date = {2018-05-22},
howpublished = {The Cancer Research Program Research day at RI-MUHC},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Enger, Shirin A.
Intensity modulated brachytherapy system for dynamic modulation of shielded catheters Presentation
Radiotherapy and Oncology, 01.04.2018, ISSN: 0167-8140, 1879-0887.
@misc{Famulari2018c,
title = {Intensity modulated brachytherapy system for dynamic modulation of shielded catheters},
author = {Gabriel Famulari and Shirin A. Enger},
url = {https://www.thegreenjournal.com/article/S0167-8140(18)30483-3/fulltext},
doi = {10.1016/S0167-8140(18)30483-3},
issn = {0167-8140, 1879-0887},
year = {2018},
date = {2018-04-01},
abstract = {www.thegreenjournal.com},
howpublished = {Radiotherapy and Oncology},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Pater, Piotr; Enger, Shirin A.
Microdosimetric Evaluation of Current and Alternative Brachytherapy Sources-A Geant4-DNA Simulation Study Journal Article
In: International Journal of Radiation Oncology, Biology, Physics, 100 (1), pp. 270–277, 2018, ISSN: 1879-355X.
@article{famulari_microdosimetric_2018,
title = {Microdosimetric Evaluation of Current and Alternative Brachytherapy Sources-A Geant4-DNA Simulation Study},
author = {Gabriel Famulari and Piotr Pater and Shirin A. Enger},
doi = {10.1016/j.ijrobp.2017.09.040},
issn = {1879-355X},
year = {2018},
date = {2018-01-01},
journal = {International Journal of Radiation Oncology, Biology, Physics},
volume = {100},
number = {1},
pages = {270--277},
abstract = {PURPOSE: Radioisotopes such as 75Se, 169Yb, and 153Gd have photon energy spectra and half-lives that make them excellent candidates as alternatives to 192Ir for high-dose-rate brachytherapy. The aim of the present study was to evaluate the relative biological effectiveness (RBE) of current (192Ir, 125I, 103Pd) and alternative (75Se, 169Yb, 153Gd) brachytherapy radionuclides using Monte Carlo simulations of lineal energy distributions.
METHODS AND MATERIALS: Brachytherapy sources (microSelectron v2 [192Ir, 75Se, 169Yb, 153Gd], SelectSeed [125I], and TheraSeed [103Pd]) were placed in the center of a spherical water phantom with a radius of 40 cm using the Geant4 Monte Carlo simulation toolkit. The kinetic energy of all primary, scattered, and fluorescence photons interacting in a scoring volume were tallied at various depths from the source. Electron tracks were generated by sampling the photon interaction spectrum and tracking all the interactions down to 10 eV using the event-by-event capabilities of the Geant4-DNA models. The dose mean lineal energy (y¯D) values were obtained through random sampling of transfer points and overlaying spherical scoring volumes within the associated volume of the tracks. The scoring volume diameter was determined by fitting the y¯D ratio for 125I to its observed RBE.
RESULTS: y¯D increased with the increasing distance from the source for 192Ir, 75Se, and 169Yb, remained constant for 153Gd and 125I, and decreased for 103Pd. The diameter at which the y¯D ratio coincided with the RBE of 1.15 to 1.20 for 125I was ∼25 to 40 nm. The RBE (reference 1 MeV photons) at high doses and dose rates for 192Ir, 75Se, 169Yb, 153Gd, 125I, and 103Pd was 1.028 to 1.034, 1.05 to 1.07, 1.12 to 1.15, 1.16 to 1.21, 1.15 to 1.20, and 1.17 to 1.22, respectively.
CONCLUSIONS: The radiation quality of the radionuclides under investigation was greater than that of high-energy photons. The present study has provided a set of values to modify the prescription doses for brachytherapy to account for the variation in radiation quality among radionuclides.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
METHODS AND MATERIALS: Brachytherapy sources (microSelectron v2 [192Ir, 75Se, 169Yb, 153Gd], SelectSeed [125I], and TheraSeed [103Pd]) were placed in the center of a spherical water phantom with a radius of 40 cm using the Geant4 Monte Carlo simulation toolkit. The kinetic energy of all primary, scattered, and fluorescence photons interacting in a scoring volume were tallied at various depths from the source. Electron tracks were generated by sampling the photon interaction spectrum and tracking all the interactions down to 10 eV using the event-by-event capabilities of the Geant4-DNA models. The dose mean lineal energy (y¯D) values were obtained through random sampling of transfer points and overlaying spherical scoring volumes within the associated volume of the tracks. The scoring volume diameter was determined by fitting the y¯D ratio for 125I to its observed RBE.
RESULTS: y¯D increased with the increasing distance from the source for 192Ir, 75Se, and 169Yb, remained constant for 153Gd and 125I, and decreased for 103Pd. The diameter at which the y¯D ratio coincided with the RBE of 1.15 to 1.20 for 125I was ∼25 to 40 nm. The RBE (reference 1 MeV photons) at high doses and dose rates for 192Ir, 75Se, 169Yb, 153Gd, 125I, and 103Pd was 1.028 to 1.034, 1.05 to 1.07, 1.12 to 1.15, 1.16 to 1.21, 1.15 to 1.20, and 1.17 to 1.22, respectively.
CONCLUSIONS: The radiation quality of the radionuclides under investigation was greater than that of high-energy photons. The present study has provided a set of values to modify the prescription doses for brachytherapy to account for the variation in radiation quality among radionuclides.
Famulari, Gabriel; Rayes, Roni F.; Enger, Shirin A.
AIM-Brachy - 5 finalists out of 42 projects in McGill Clinical Innovation Competition and Hakim Family Prize. Miscellaneous
AIMBrachy, 2018.
@misc{Famulari2018,
title = {AIM-Brachy - 5 finalists out of 42 projects in McGill Clinical Innovation Competition and Hakim Family Prize.},
author = {Gabriel Famulari and Roni F. Rayes and Shirin A. Enger},
year = {2018},
date = {2018-01-01},
howpublished = {AIMBrachy},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}
Famulari, Gabriel; Enger, Shirin A.
Top 5 abstract at the ESTRO annual meeting Miscellaneous
ESTRO Annual meeting, 2018.
@misc{Famulari2018b,
title = {Top 5 abstract at the ESTRO annual meeting},
author = {Gabriel Famulari and Shirin A. Enger},
year = {2018},
date = {2018-01-01},
abstract = {Intensity-modulated brachytherapy system for dynamic modulation of shielded catheters, ESTRO Annual meeting. Barcelona, Spain. Selected as one of the five abstracts out of the numerous submitted at the ESTRO conference to highlight the type of innovative science presented in an area and published in the conference report. },
howpublished = {ESTRO Annual meeting},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}
2017
Famulari, Gabriel; Urlich, Tomas; Armstrong, Andrea; Enger, Shirin A.
Practical aspects of 153Gd as a radioactive source for use in brachytherapy Journal Article
In: Applied Radiation and Isotopes: Including Data, Instrumentation and Methods for Use in Agriculture, Industry and Medicine, 130 , pp. 131–139, 2017, ISSN: 1872-9800.
@article{famulari_practical_2017,
title = {Practical aspects of 153Gd as a radioactive source for use in brachytherapy},
author = {Gabriel Famulari and Tomas Urlich and Andrea Armstrong and Shirin A. Enger},
doi = {10.1016/j.apradiso.2017.09.028},
issn = {1872-9800},
year = {2017},
date = {2017-12-01},
journal = {Applied Radiation and Isotopes: Including Data, Instrumentation and Methods for Use in Agriculture, Industry and Medicine},
volume = {130},
pages = {131--139},
abstract = {The goal of this study was to investigate the production, purification and immobilization techniques for a 153Gd brachytherapy source. We have investigated the maximum attainable specific activity of 153Gd through the irradiation of Gd2O3 enriched to 30.6% 152Gd at McMaster Nuclear Reactor. The advantage of producing 153Gd through this production pathway is the possibility to irradiate pre-sealed pellets of 152Gd enriched Gd2O3, thereby removing the need to perform chemical separation with large quantities of radio-impurities. However, small amounts of long-lived impurities are produced from the irradiation of enriched 152Gd targets due to traces of Eu in the sample. If the amount of impurities produced is deemed unacceptable, 153Gd can be isolated as an aqueous solution, chemically separated from impurities and loaded onto a sorbent with a high affinity for Gd before encapsulation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Famulari, Gabriel; Pater, Piotr; Enger, Shirin A.
Microdosimetry calculations for monoenergetic electrons using Geant4-DNA combined with a weighted track sampling algorithm Journal Article
In: Physics in Medicine and Biology, 62 (13), pp. 5495–5508, 2017, ISSN: 1361-6560.
@article{famulari_microdosimetry_2017,
title = {Microdosimetry calculations for monoenergetic electrons using Geant4-DNA combined with a weighted track sampling algorithm},
author = {Gabriel Famulari and Piotr Pater and Shirin A. Enger},
doi = {10.1088/1361-6560/aa71f6},
issn = {1361-6560},
year = {2017},
date = {2017-07-01},
journal = {Physics in Medicine and Biology},
volume = {62},
number = {13},
pages = {5495--5508},
abstract = {The aim of this study was to calculate microdosimetric distributions for low energy electrons simulated using the Monte Carlo track structure code Geant4-DNA. Tracks for monoenergetic electrons with kinetic energies ranging from 100 eV to 1 MeV were simulated in an infinite spherical water phantom using the Geant4-DNA extension included in Geant4 toolkit version 10.2 (patch 02). The microdosimetric distributions were obtained through random sampling of transfer points and overlaying scoring volumes within the associated volume of the tracks. Relative frequency distributions of energy deposition f(textgreaterE)/f(textgreater0) and dose mean lineal energy ([Formula: see text]) values were calculated in nanometer-sized spherical and cylindrical targets. The effects of scoring volume and scoring techniques were examined. The results were compared with published data generated using MOCA8B and KURBUC. Geant4-DNA produces a lower frequency of higher energy deposits than MOCA8B. The [Formula: see text] values calculated with Geant4-DNA are smaller than those calculated using MOCA8B and KURBUC. The differences are mainly due to the lower ionization and excitation cross sections of Geant4-DNA for low energy electrons. To a lesser extent, discrepancies can also be attributed to the implementation in this study of a new and fast scoring technique that differs from that used in previous studies. For the same mean chord length ([Formula: see text]), the [Formula: see text] calculated in cylindrical volumes are larger than those calculated in spherical volumes. The discrepancies due to cross sections and scoring geometries increase with decreasing scoring site dimensions. A new set of [Formula: see text] values has been presented for monoenergetic electrons using a fast track sampling algorithm and the most recent physics models implemented in Geant4-DNA. This dataset can be combined with primary electron spectra to predict the radiation quality of photon and electron beams.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Famulari, Gabriel; Pater, Piotr; Enger, Shirin A.
Microdosimetric evaluation of intermediate-energy brachytherapy sources using Geant4-DNA Presentation
Radiotherapy and Oncology, 01.01.2017.
@misc{Famulari2017,
title = {Microdosimetric evaluation of intermediate-energy brachytherapy sources using Geant4-DNA},
author = {Gabriel Famulari and Piotr Pater and Shirin A. Enger},
year = {2017},
date = {2017-01-01},
howpublished = {Radiotherapy and Oncology},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Renaud, Marc-André; Enger, Shirin A.
An intensity modulated delivery system for prostate brachytherapy using intermediate energy sources Presentation
Medical Physics, 01.01.2017.
@misc{Famulari2017b,
title = {An intensity modulated delivery system for prostate brachytherapy using intermediate energy sources},
author = {Gabriel Famulari and Marc-André Renaud and Shirin A. Enger},
year = {2017},
date = {2017-01-01},
howpublished = {Medical Physics},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Enger, Shirin A.
A Novel Delivery System for High Dose Rate Intensity Modulated Brachytherapy with Intermediate Energy Brachytherapy Radiation Sources Such as 169Yb Presentation
Brachytherapy, 01.01.2017.
@misc{Famulari2017c,
title = {A Novel Delivery System for High Dose Rate Intensity Modulated Brachytherapy with Intermediate Energy Brachytherapy Radiation Sources Such as 169Yb},
author = {Gabriel Famulari and Shirin A. Enger},
year = {2017},
date = {2017-01-01},
howpublished = {Brachytherapy},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Renaud, Marc-André; Enger, Shirin A.
Top ranking submission to the Young Investigator Symposium Presentation
COMP Annual meeting, Young Investigator Symposium, 01.01.2017.
@misc{nokey,
title = {Top ranking submission to the Young Investigator Symposium},
author = {Gabriel Famulari and Marc-André Renaud and Shirin A. Enger},
year = {2017},
date = {2017-01-01},
urldate = {2017-01-01},
abstract = {An intensity-modulated delivery system for prostate brachytherapy using intermediate energy sources. This abstract was selected as one of the best abstracts to compete in the young investigator symposium.},
howpublished = {COMP Annual meeting, Young Investigator Symposium},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
2016
Renaud, Marc-André; Famulari, Gabriel; Seuntjens, Jan; Enger, Shirin A.
Column generation-based Monte Carlo treatment planning for rotating shield brachytherapy Presentation
Radiotherapy and Oncology, 01.01.2016.
@misc{Renaud2016,
title = {Column generation-based Monte Carlo treatment planning for rotating shield brachytherapy},
author = {Marc-André Renaud and Gabriel Famulari and Jan Seuntjens and Shirin A. Enger},
year = {2016},
date = {2016-01-01},
urldate = {2016-01-01},
howpublished = {Radiotherapy and Oncology},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
Famulari, Gabriel; Armstrong, Andrea; Enger, Shirin A.
Production of Gd-153 as a source isotope for use in rotating shield high dose rate brachytherapy Presentation
Radiotherapy and Oncology, 01.01.2016.
@misc{Famulari2016,
title = {Production of Gd-153 as a source isotope for use in rotating shield high dose rate brachytherapy},
author = {Gabriel Famulari and Andrea Armstrong and Shirin A. Enger},
year = {2016},
date = {2016-01-01},
howpublished = {Radiotherapy and Oncology},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}