Dr. Mark Ruschin, Sunnybrook Odette Cancer Centre, Toronto, ON

Project Title: Comparison of healthy tissue sparing using different radiation delivery devices for focal irradiation of multiple brain metastases

Dr. Ruschin’s project is funded in memory of and through the generosity of Donald J.T.A. de Jong

Project Summary:

Brain metastases occur in 20-40% of people with cancer, and will lead to over 7,000 diagnosed cases in 2013. For these individuals, quality of life is of the utmost importance. The traditional approach to managing patients with brain metastases is to perform whole brain radiation, in which the entire brain receives a uniform dose of radiation in order to stop the diagnosed brain metastases from growing, and to prevent new brain metastases from forming.

Whole brain radiotherapy, however, adversely affects cognitive function and limits further treatment should additional brain metastases develop. Focal radiation targets individual brain metastases and spares the healthy brain, which maintains better cognitive function and provides excellent tumour control. Various radiation therapy technologies are capable of focal radiation.

One new device has recently become Health Canada approved and exhibits improved characteristics over predecessors such as faster radiation delivery, and lower leakage radiation. We hypothesize that this new device can be used to treat patients with multiple brain metastases in a focal/ablative fashion, thus better preserving patients’ cognitive function and improving quality of life. The focus of this work is technique development and a comparison of radiation dose distributions to the current standard.

Final report:

The project involved development and evaluation of an arc-based technique using an emerging technology to effectively delivery focal radiation to multiple brain metastases. In 2013, the Agility linear accelerator (Elekta AB, Stockholm, Sweden) was just coming to market in Canada and consisted of features that could potentially reduce the normal tissue radiation dose received by the brain compared to the existing systems at that time. The primary objective was thus to implement the technique and measure reduction in normal brain tissue radiation dose compared to our standard technique. Additionally, we needed an improved method for quality assurance (QA) of the device to ensure safe treatment. Read more from the final report (PDF).

Publications:

Investigation of two linear accelerator head designs for treating brain metastases with hypofractionated volumetric-modulated arc radiotherapy
Mark Ruschin, PhD, Arjun Sahgal, MD, Sara Iradji, MSc , Hany Soliman, MD, Claudia Leavens, PhD and Young Lee, PhD
May 2016
British Institute of Radiology