Continuing Professional Development ‐ Radiation Therapy

Maximise your CPD by reading the following article and answer the five questions. Please remember to self‐claim your CPD and retain your supporting evidence. Answers will be available via the QR code and online at https://www.asmirt.org/news‐and‐publications/jmrs.

Radiation Therapy – Original Article

The effect of imaging modality (magnetic resonance imaging vs. computed tomography) and patient position (supine vs. prone) on target and organ at risk doses in partial breast irradiation

Brown E, Dundas K, Surjan Y, Miller D, Lim K, Boxer M, et al. (2021) J Med Radiat Sci. https://doi.org/10.1002/jmrs.453

1. What was the potential benefit of MRI derived target volumes for partial breast irradiation (PBI) planning?

   1. Larger region of the breast receiving radiation

   2. Smaller region of the breast receiving radiation

   3. Quicker planning time for patients

   4. MRI is already the sole basis of target delineation in radiotherapy planning

2. How were the target volumes created for this investigation?

   1. This investigation builds on previous work where radiation oncologists and radiologists previously defined seroma volumes on CT and MRI

   2. Qualified radiation therapists defined these volumes as seen on each modality

   3. Patients were recruited as they appeared in clinic and were contoured by radiation oncologists as per routine practice

   4. Radiation oncologists and radiologists contoured all volumes on MRI alone

3. Which modality and positioning method had the highest rate of dose/volume compliance?

   1. CT supine

   2. CT prone

   3. MRI supine

   4. MRI prone

4. What percentage of dose/volume non‐compliant plans were left sided?

   1. 0%

   2. 25%

   3. 50%

   4. 100%

5. In this cohort, the doses to PTVs and OARs from MRI derived target volumes in PBI resulted in which of the following?

   1. Poorer results

   2. Better results

   3. No statistical difference

   4. A statistical difference

Recommended further reading:

1. Charaghvandi KR, Van't Westeinde T, Yoo S, Houweling AC, Rodrigues A, Verkooijen HM, et al. Single dose partial breast irradiation using an MRI linear accelerator in the supine and prone treatment position. Clin Transl Radiat Oncol. 2019 Jan; 14: 1‐7.

2. Pogson EM, Delaney GP, Ahern V, Boxer MM, Chan C, David S, et al. Comparison of Magnetic Resonance Imaging and Computed Tomography for Breast Target Volume Delineation in Prone and Supine Positions. Int J Radiat Oncol Biol Phys. 2016 Nov; 96(4): 905‐12.

3. Dundas K, Pogson EM, Batumalai V, Delaney GP, Boxer MM, Yap ML, et al. The impact of imaging modality (CT vs MRI) and patient position (supine vs prone) on tangential whole breast radiation therapy planning. Pract Radiat Oncol. 2018 May‐Jun; 8(3): e87‐e97.

Answers

Scan this QR code to find the answers, or visit https://www.asmirt.org/news‐and‐publications/jmrs

J Med Radiat Sci. 68(2021) 212–212