Jonathan Kalinowski

Ph.D. Student
Medical Physics
Department of Oncology

Bio

Originally from Massachusetts, USA, Jonathan came to Montréal to study Physics at McGill University in 2017. He began working with the Enger Lab in January 2020, and graduated with a B.Sc. in Physics in August 2020. After a year as a research assistant in the lab, Jonathan returned to McGill for his M.Sc. in Medical Physics, and graduated in 2024. He is currently persuing his Ph.D in Physics with the Enger Lab. His graduate research centers on the translation of rectal intensity modulated brachytherapy to the clinic.

Current Projects

Toward the Clinical Implementation of Intensity Modulated Brachytherapy for the Treatment of Rectal Cancer (M.Sc and Ph.D project)

Intensity modulated brachytherapy (IMBT) utilizes dynamically-rotating metallic shields to shield healthy tissue and provide conformal dose coverage of tumours. Our lab has designed an intensity modulated brachytherapy shielded applicator for rectal cancer, and have shown using Monte Carlo simulations that it offers a substantial dose reduction to organs at risk. The goal of my M.Sc and Ph.D centers around developing and creating hardware and software technology to take rectal intensity modulated brachytherapy from a hypothetical to a treatment that can be delivered clinically.

Development of a delivery system for rectal intensity modulated brachytherapy

Components of the rectal intensity modulated brachytherapy will include the 180° degree tungsten shield, mould applicator, rotation system, remote afterloader, and rotation software. These separate technologies must be combined into a robust system that is capable of delivering a treatment plan.

Design of a 3D printed patient-specific deformable pelvic phantom for rectal intensity modulated brachytherapy and characterization of 3D printed materials

We are designing a 3D printed, patient-specific, deformable pelvic phantom to assess anatomical changes and perform dose quality assurance for treatment plans. We are also characterizing the non-water-equivalent materials used in the phantom using novel methods to ensure that their radiation attenuation properties can be properly simulated.

Creation of an optimization workflow for rectal intensity modulated brachytherapy

With an extra degree of freedom, a rectal intensity modulated brachytherapy dose optimization protocol must go beyond current clinical optimization techniques. We are investigating new optimization methods to achieve the most conformal doses possible with intensity modulated brachytherapy

Development of a Selenium-75 brachytherapy source

Continuing the M.Sc work of Jake Reid, I will work towards the creation and characterization of a selenium-75 brachytherapy source with a clinically-viable activity (~20 Ci).

RapidBrachyTG43: A Geant4-based TG-43 Parameter Calculation Engine for Brachytherapy Applications

The American Association of Physicists in Medicine Task Group 43 (TG-43) report specifies an analytic formalism for brachytherapy dose calculations, approximating patients as effectively infinite water phantoms and ignoring differential scattering and attenuation by brachytherapy hardware, patient tissues, and air interfaces. TG-43 is still in use as the recommended dose calculation method for clinical brachytherapy dosimetry. This project involved the development of a Geant4 usercode and accompanying module of RapidBrachyMCTPS to facilitate TG-43 parameter calculations for brachytherapy sources. The module also enables the use of these parameters in fast dose to water calculations in RapidBrachyMCTPS.

Monte Carlo-based Dosimetry for GRID Radiotherapy

Spatially-fractionated radiotherapy, also known as GRID, involves the placement of a perforated metallic block in the beam of a conventional linear accelerator, resulting in a treatment field consisting of many spatially-separated ‘pencil’ beams. GRID is used for single-fraction dose escalation for large tumours, offering better control and reduced side-effects versus equivalent doses in the open-field case. Jonathan will use Geant4-based Monte Carlo simulations to investigate the dose distributions delivered in patients treated with GRID and evaluate the accuracy of the current ‘pencil and paper’ dosimetry protocol used for this technique.

2024

Kalinowski, Jonathan; Enger, Shirin A

RapidBrachyTG43: A Geant4-based TG-43 parameter and dose calculation module for brachytherapy dosimetry Journal Article

In: Medical Physics, vol. 51, no. 5, pp. 3746–757, 2024.

Links | BibTeX

2023

Rahbaran, Maryam; Kalinowski, Jonathan; DeCunha, Joseph; Croce, Kevin; Bergmark, Brian; Devlin, Philip; Tsui, James; Enger, Shirin A.

Development Of a Novel Dosimetry Software for Patient-specific Intravascular Brachytherapy Treatment Planning on Optical Coherence Tomography Images Presentation

23.09.2023, (COMP-CARO 2023 Joint Scientific Meeting).

BibTeX

Rahbaran, Maryam; Kalinowski, Jonathan; Tsui, James; DeCunha, Joseph; Croce, Kevin; Bergmark, Brian; Devlin, Philip; Enger, Shirin A.

Development Of a Novel Dosimetry Software for Patient-specific Intravascular Brachytherapy Treatment Planning on Optical Coherence Tomography Images Presentation

22.06.2023, (2023 American Brachytherapy Society (ABS) Annual Meeting, Vancouver, Canada).

BibTeX

2022

Kalinowski, Jonathan

McGill Faculty of Medicine and Health Sciences Internal Studentship award

2022.

Abstract | Links | BibTeX

Rahbaran, Maryam; Kalinowski, Jonathan; Tsui, James; DeCunha, Joseph; Enger, Shirin A.

Monte-Carlo Based Simulations of the Uncertainties in Clinical Water-Based Intravascular Brachytherapy Dosimetry Presentation

11.04.2022.

Abstract | BibTeX

@misc{nokey,

title = {Monte-Carlo Based Simulations of the Uncertainties in Clinical Water-Based Intravascular Brachytherapy Dosimetry},

author = {Maryam Rahbaran and Jonathan Kalinowski and James Tsui and Joseph DeCunha and Shirin A. Enger},

year = {2022},

date = {2022-04-11},

urldate = {2022-04-11},

journal = {MCMA},

abstract = {"Introduction

Coronary artery disease (CAD) is the most common form of cardiovascular disease and is caused by excess plaque along the arterial wall, blocking blood flow to the heart (stenosis). Percutaneous transluminal coronary angioplasty widens a narrowed artery, leaving behind metal stents (1). However, in-stent restenosis (ISR) may occur due to damage to the arterial wall tissue, triggering neointimal hyperplasia which produces fibrotic and calcified plaques, narrowing the artery again. Drug-eluting stents (DES) slowly release medication to inhibit neointimal hyperplasia to prevent ISR but they fail in 3% to 20% of cases (2). Intravascular brachytherapy (IVBT), which uses b-emitting radionuclides to prevent ISR, is used in these failed cases. However, current dosimetry for IVBT is water based and does not consider attenuation of the radiation by heterogeneities such as the IVBT device guidewire, non-uniform distribution of calcified plaques, and stent material, or the angular dependence of dose distribution (3, 4, 5). The aim of this study was to investigate the uncertainties in clinical water based IVBT dosimetry, considering the effect of heterogeneities on dose distribution.

Materials & Methods

An inhouse Monte-Carlo based dosimetry package for IVBT applications based on Geant4 10.04 (patch 2) was developed. Patient’s artery was modelled as a 32 mm long, 8.4 mm diameter cylinder comprised of three layers: tunica media, represented with muscle, tunica intima, represented with fibrotic plaque, and tunica adventitia, represented with collagen. These layers had mass densities 1.06 g/cm3, 1.22 g/cm3 and 1.07 g/cm3 respectively. The innermost layer consisted of calcified plaque of density 1.45 g/cm3 with varying thicknesses between 0.9 and 1.9 mm with an eccentric shape and a rough surface. The stents had similar composition to Boston Scientific Synergy stents and were modelled to not overlap. The Novoste Beta-Cath 3.5F IVBT device model was used, which has a 90Sr90Y source. The geometry is shown in Figure 1a. A cylindrical scoring geometry was implemented. Two set of simulations were performed. In the first simulation called water phantom, the entire system consisted of water with unit density, and dose to water was calculated similar to the clinical water based dosimetry. In the second simulation called the artery model proper material and mass densities were assigned to each component. To ensure uncertainties below 0.8% within a 1 mm radial distance to the source and 2% within 4.2 mm from the source, 100 million decay events were simulated. The Penelope physics list was used to simulate the electromagnetic interactions between particles. Average, minimum, and maximum dose was calculated at 2.0 mm from the source center and directly and 1 mm behind the outermost stents and guidewire. Absorbed dose was normalized to 23 Gy at 2.0 mm from the source center.

Results

International Conference on Monte Carlo Techniques for Medical Applications, 2022

Compared to the water phantom (Figure 1b), average dose in the artery model (Figure 1c) was attenuated by 50.9% at 2 mm from the source centre and directly behind the guidewire and outermost stent by 66.2%, and by 69.5% 1 mm behind this region. There was significant variation in dose around the source due to the guidewire attenuating dose the most, and heterogeneous distribution of calcification.

Discussion & Conclusions

Dosimetry for IVBT based on dose rate in water is not accurate. Heterogeneities need to be considered to deliver adequate dose to the lesion area. Stent material, heterogenous distribution of calcification and the off cantered placement of the guidewire affects the uniformity of dose distribution around the source. Patients may benefit from personalized treatment planning taking dose-attenuating by different tissue/material heterogeneities into account.

References

[1] Virani, Salim, S., et al. ""Heart Disease and Stroke Statistics—2020 Update"". Circulation, vol. 141, no. 9, March 03, 2020, pp. e336. doi: 10.1161/CIR.0000000000000757.

[2] Lee M, Banka G. In-stent restenosis. Interv Cardiol Clin 2016;5: 211e220.

[3] Chiu-Tsao ST, Schaart DR, Soares CG, et al. Dose calculation formalisms and consensus dosimetry parameters for intravascular brachytherapy dosimetry: Recommendations of the AAPM Therapy Physics Committee Task Group No. 149. Med Phys 2007;34: 4126e4157.

[4] Rivard MJ, Coursey BM, DeWerd LA, et al. Update of AAPM Task Group No. 43 Report: A revised AAPM protocol for brachytherapy dose calculations. Med Phys 2004;31:633e674.

[5] Nath R, Amols H, Coffey C, et al. Intravascular brachytherapy physics: Report of the AAPM Radiation Therapy Committee Task group No. 60. Med Phys 1999;26:119e152.’

[6] Agostinelli S, Allison J, Amako K, et al. Geant4da simulation toolkit. Nucl Instrum Methods Phys Res 2003;506:230e303."},

keywords = {},

pubstate = {published},

tppubtype = {presentation}

}

"Introduction
Coronary artery disease (CAD) is the most common form of cardiovascular disease and is caused by excess plaque along the arterial wall, blocking blood flow to the heart (stenosis). Percutaneous transluminal coronary angioplasty widens a narrowed artery, leaving behind metal stents (1). However, in-stent restenosis (ISR) may occur due to damage to the arterial wall tissue, triggering neointimal hyperplasia which produces fibrotic and calcified plaques, narrowing the artery again. Drug-eluting stents (DES) slowly release medication to inhibit neointimal hyperplasia to prevent ISR but they fail in 3% to 20% of cases (2). Intravascular brachytherapy (IVBT), which uses b-emitting radionuclides to prevent ISR, is used in these failed cases. However, current dosimetry for IVBT is water based and does not consider attenuation of the radiation by heterogeneities such as the IVBT device guidewire, non-uniform distribution of calcified plaques, and stent material, or the angular dependence of dose distribution (3, 4, 5). The aim of this study was to investigate the uncertainties in clinical water based IVBT dosimetry, considering the effect of heterogeneities on dose distribution.

Materials & Methods
An inhouse Monte-Carlo based dosimetry package for IVBT applications based on Geant4 10.04 (patch 2) was developed. Patient’s artery was modelled as a 32 mm long, 8.4 mm diameter cylinder comprised of three layers: tunica media, represented with muscle, tunica intima, represented with fibrotic plaque, and tunica adventitia, represented with collagen. These layers had mass densities 1.06 g/cm3, 1.22 g/cm3 and 1.07 g/cm3 respectively. The innermost layer consisted of calcified plaque of density 1.45 g/cm3 with varying thicknesses between 0.9 and 1.9 mm with an eccentric shape and a rough surface. The stents had similar composition to Boston Scientific Synergy stents and were modelled to not overlap. The Novoste Beta-Cath 3.5F IVBT device model was used, which has a 90Sr90Y source. The geometry is shown in Figure 1a. A cylindrical scoring geometry was implemented. Two set of simulations were performed. In the first simulation called water phantom, the entire system consisted of water with unit density, and dose to water was calculated similar to the clinical water based dosimetry. In the second simulation called the artery model proper material and mass densities were assigned to each component. To ensure uncertainties below 0.8% within a 1 mm radial distance to the source and 2% within 4.2 mm from the source, 100 million decay events were simulated. The Penelope physics list was used to simulate the electromagnetic interactions between particles. Average, minimum, and maximum dose was calculated at 2.0 mm from the source center and directly and 1 mm behind the outermost stents and guidewire. Absorbed dose was normalized to 23 Gy at 2.0 mm from the source center.

Results
International Conference on Monte Carlo Techniques for Medical Applications, 2022
Compared to the water phantom (Figure 1b), average dose in the artery model (Figure 1c) was attenuated by 50.9% at 2 mm from the source centre and directly behind the guidewire and outermost stent by 66.2%, and by 69.5% 1 mm behind this region. There was significant variation in dose around the source due to the guidewire attenuating dose the most, and heterogeneous distribution of calcification.

Discussion & Conclusions
Dosimetry for IVBT based on dose rate in water is not accurate. Heterogeneities need to be considered to deliver adequate dose to the lesion area. Stent material, heterogenous distribution of calcification and the off cantered placement of the guidewire affects the uniformity of dose distribution around the source. Patients may benefit from personalized treatment planning taking dose-attenuating by different tissue/material heterogeneities into account.

References
[1] Virani, Salim, S., et al. ""Heart Disease and Stroke Statistics—2020 Update"". Circulation, vol. 141, no. 9, March 03, 2020, pp. e336. doi: 10.1161/CIR.0000000000000757.
[2] Lee M, Banka G. In-stent restenosis. Interv Cardiol Clin 2016;5: 211e220.
[3] Chiu-Tsao ST, Schaart DR, Soares CG, et al. Dose calculation formalisms and consensus dosimetry parameters for intravascular brachytherapy dosimetry: Recommendations of the AAPM Therapy Physics Committee Task Group No. 149. Med Phys 2007;34: 4126e4157.
[4] Rivard MJ, Coursey BM, DeWerd LA, et al. Update of AAPM Task Group No. 43 Report: A revised AAPM protocol for brachytherapy dose calculations. Med Phys 2004;31:633e674.
[5] Nath R, Amols H, Coffey C, et al. Intravascular brachytherapy physics: Report of the AAPM Radiation Therapy Committee Task group No. 60. Med Phys 1999;26:119e152.’
[6] Agostinelli S, Allison J, Amako K, et al. Geant4da simulation toolkit. Nucl Instrum Methods Phys Res 2003;506:230e303."