McGill.CA / Medical Physics Unit / People / Faculty & Staff / Shirin A. Enger

Novel Brachytherapy Technology

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​​High dose rate brachytherapy (HDR-BT), especially with magnetic resonance image (MRI) guidance, is one of the most effective and precise radiation delivery modalities with major impact on gynaecological, genitourinary and prostate cancers. HDR-BT has been adopted rapidly in Canada, USA and Europe and is cost efficient compared to other treatment modalities. About 60% of the radiation oncology clinics across Canada offer this treatment modality with gynaecologic, genitourinary and prostate cancers as the most commonly treated cancer sites. Due to the growing evidence of the benefits of HDR-BT and increasing number of cancer patients, the treatment modality has been successfully used on other cancer sites as well. In HDR-BT, encapsulated high activity radiation sources are temporarily placed directly into or near localized tumours using needles, plastic catheters or other specialized applicators giving a high radiation dose to the tumour while the dose to sensitive organs at risk (OARs) surrounding the tumour is lower. However, radiation sources used in BT conventionally provide rotationally symmetric dose distributions, and deliver high dose to tumours with often poor target conformity due to the non-symmetrical shape of the tumours resulting in dose spillage to OARs.

My research group is developing the next generation of HDR-BT technology with new radiation sources, an intensity modulated brachytherapy delivery system and accurate dose calculation and treatment planning software to tailor the delivered radiation dose to the shape of the tumour and spare healthy tissues. This will increase the tumour control probability, while simultaneously reducing toxicity, which will increase the quality of life of the patients.

 

Peer reviewed publications and published conference presentations

Journal publications

  • Morcos M, Antaki M, Viswanathan AN, Enger SA. A novel minimally invasive dynamic shield intensity modulated brachytherapy system for cervical cancer. Medical Physics. In press (2020).
  • Antaki M, Deufel C, Enger SA. Fast mixed integer optimization (FMIO) for high dose rate brachytherapy. Physics in Medicine & Biology. In press (2020).
  • Mao X, Pineau J, Keyes R, Enger SA. RapidBrachyDL: Rapid Radiation Dose Calculations in Brachytherapy via Deep Learning. International Journal of Radiation Oncology • Biology • Physics. In press (2020).
  • Famulari G, Alfieri J, Duclos M, Vuong T, Enger SA. Can intermediate-energy sources lead to elevated bone doses for prostate and head & neck high-dose-rate brachytherapy? Brachytherapy. 19(2):255-263 (2020).
  • Famulari G, Duclos M, Enger SA. A novel 169Yb‐based dynamic‐shield intensity modulated brachytherapy delivery system for prostate cancer. Medical Physics. 47(3):859-868 (2020).
  • Shoemaker T, Vuong T, Glickman H, Kaifi S, Famulari G, Enger SA. Dosimetric Considerations for Ytterbium-169, Selenium-75 and Iridium-192 Radioisotopes in High Dose Rate Endorectal Brachytherapy. International Journal of Radiation Oncology • Biology • Physics. 105(4):875-883 (2019).
  • DeCunha J, Enger SA. Investigation of a New Device to Improve Dosimetric Outcomes in Intravascular Brachytherapy. Brachytherapy. 17(3):634-643 (2018).
  • Famulari G, Urlich T, Armstrong A, Enger SA, Practical aspects of 153Gd as a radioactive source for use in brachytherapy. Applied Radiation and Isotopes. 130:131–139 (2017).
  • DeCunha J, Janicki C, Enger SA, A retrospective analysis of catheter-based sources in intravascular brachytherapy. Brachytherapy, 16(3):586-596 (2017).

Conference presentations (oral)

  • Famulari G, Enger SA, Evaluation of the intershield attenuation effect for a new intensity modulated brachytherapy system for prostate cancer. American Association of Physicists in Medicine (AAPM) 61st Annual Meeting, July 18 (2019). San Antonio, Tx, USA.
  • Famulari G, Enger SA, Monte Carlo dosimetry of a custom-made 169Yb source for intensity modulated brachytherapy. MCMA, June 20 (2019). Montreal, QC, Canada.
  • Morcos M, Enger SA, Monte Carlo Dosimetry Study of Novel Rotating MRI-Compatible Shielded Tandems for Intensity Modulated Cervix Brachytherapy. MCMA, June 20 (2019). Montreal, QC, Canada.
  • Famulari G, Enger SA. Dosimetric characterization of a new 169Yb source for high dose rate brachytherapy. American Brachytherapy Society (ABS) Annual Meeting, June 8 (2019). Miami, Fl, USA.
  • Marcos M, Enger SA. MR-Compatible Intensity Modulated Brachytherapy Applicator for Cervical Cancer. American Brachytherapy Society (ABS) Annual Meeting, June 8 (2019). Miami, Fl, USA.
  • Famulari G, Enger SA. Urethra sparing with intensity modulated brachytherapy for prostate cancer. Curietherapies, May 17 (2019). Montreal, QC, Canada.
  • Marcos M, Enger SA. MR-Compatible Intensity Modulated Brachytherapy for the Treatment of Locally Advanced Cervical Cancer. Curietherapies, May 17 (2019). Montreal, QC, Canada. 
  • Famulari G, Enger SA. Intensity modulated brachytherapy for prostate cancer: plan quality, robustness and delivery time. ESTRO 38, April 28 (2019). Milan, Italy.
  • Famulari G, Enger SA. Intensity modulated brachytherapy system for dynamic modulation of shielded catheters. ESTRO Annual meeting, April 2018. Radiotherapy and Oncology. 127: S90 (2018). Barcelona, Spain.
    • Selected as selected as one of the five abstracts at the European society for radiotherapy and oncology conference to highlight the type of innovative science presented in an area and published in the conference report.
  • Famulari G, Enger SA. AIMBrachy, A Novel Radiation Delivery System. The Cancer Research Program Research day at RI-MUHC. May 22nd (2018). Montreal, Canada.
  • Famulari G, Renaud MA, Enger SA, An intensity modulated delivery system for prostate brachytherapy using intermediate energy sources. Medical Physics, 44 (8):4370 (2017).
  • DeCunha J, Enger SA, Resolving dosimetric issues in intravascular brachytherapy. Medical Physics, 44 (8):32 (2017).
  • Famulari G, Enger SA, A Novel Delivery System for High Dose Rate Intensity Modulated Brachytherapy with Intermediate Energy Brachytherapy Radiation Sources Such as 169Yb. Brachytherapy, 16(3):S23 (2017).
  • Renaud MA, Famulari G, Seuntjens J, Enger SA, Column generation-based Monte Carlo treatment planning for rotating shield brachytherapy. Radiotherapy and Oncology, 119:S118 (2016).
  • Renaud MA, Flynn R, Seuntjens J, Enger SA, Rotating Shield High Dose Rate Brachytherapy with 153Gd and 75Se isotopes. Medical Physics, 42, 3455 (2015).

Conference presentations (poster)

  • DeCunha J, Enger SA, Investigation of a New Device to Improve Dosimetric Outcomes in Intravascular Brachytherapy. Brachytherapy, 16 (3):S80 (2017).
  • Famulari G, Armstrong A, Urlich T, Enger SA, Production of Gd-153 as a source isotope for use in rotating shield high dose rate brachytherapy. Radiotherapy and Oncology, 119:S472 (2016).

 

Intensity Modulated Brachytherapy

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From left to right: Shirin A. Enger (Assistant Professor), Gabriel Famulari (PhD Candidate), Marc Morcos (PhD Candidate)

In this project we are developing an intensity modulated brachytherapy delivery system, that will dynamically direct the radiation into the tumours and away from healthy tissue i.e. the dose distributions will better conform to the shape of the tumour by incorporation of metallic shields inside the brachytherapy catheters. By developing and enabling intensity modulated brachytherapy, we aim to significantly improve the potentials of brachytherapy with reduced toxicity, improved therapeutic ratio and clinical outcomes as end-goals. 

 

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Radiation Source Development for use in Brachytherapy

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From left to right: Shirin A. Enger (Assistant Professor), Gabriel Famulari (PhD Candidate)

The motivation behind design and development of novel brachytherapy radiation sources is the possibility to shield the radiation sources locally, maximising the radiation dose to the tumour with less dose spillage to radiation sensitive healthy tissues. Additionally, less shielding will be required for the treatment rooms, enabling more cancer centres to offer brachytherapy as a treatment modality to their patients. In this project new radiation sources for use in high dose rate brachytherapy with much lower energy than the currently used radiation source, Iridium-192, are investigated and developed.

 

Intravascular Brachytherapy

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From left to right: Shirin A. Enger (Assistant Professor), Joseph DeCunha (MSc Candidate)

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.

 

 

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