Is there a clinical benefit with a smooth compensator design compared with a plunged compensator design for passive scattered protons?

Journal Article · Wed Apr 01 00:00:00 EDT 2015 · Medical Dosimetry

DOI:https://doi.org/10.1016/J.MEDDOS.2014.07.004· OSTI ID:22462422

Powers, Adam; Dolormente, Keith; Oommen, Sneha; Tiwari, Akhil ^[1]; Palmer, Matt ^[2]; Zhu, Xiaorong R.; Li, Heng; Sahoo, Narayan; Wisdom, Paul ^[3]; Velasco, Kyle ^[4]; Erhart, Kevin; Stanley, Henry ^[5]; Nguyen, Bao-Ngoc T. ^[2]

---

1. University of Texas School of Allied Health-Medical Dosimetry, Houston, TX (United States)
2. MD Anderson Department of Radiation Oncology, Houston, TX (United States)
3. MD Anderson Department of Radiation Physics, Houston, TX (United States)
4. Radiation Oncology Resources, Goshen, IN (United States)
5. Decimal, Inc, Sanford, FL (United States)

In proton therapy, passive scattered proton plans use compensators to conform the dose to the distal surface of the planning volume. These devices are custom made from acrylic or wax for each treatment field using either a plunge-drilled or smooth-milled compensator design. The purpose of this study was to investigate if there is a clinical benefit of generating passive scattered proton radiation treatment plans with the smooth compensator design. We generated 4 plans with different techniques using the smooth compensators. We chose 5 sites and 5 patients for each site for the range of dosimetric effects to show adequate sample. The plans were compared and evaluated using multicriteria (MCA) plan quality metrics for plan assessment and comparison using the Quality Reports [EMR] technology by Canis Lupus LLC. The average absolute difference for dosimetric metrics from the plunged-depth plan ranged from −4.7 to +3.0 and the average absolute performance results ranged from −6.6% to +3%. The manually edited smooth compensator plan yielded the best dosimetric metric, +3.0, and performance, + 3.0% compared to the plunged-depth plan. It was also superior to the other smooth compensator plans. Our results indicate that there are multiple approaches to achieve plans with smooth compensators similar to the plunged-depth plans. The smooth compensators with manual compensator edits yielded equal or better target coverage and normal tissue (NT) doses compared with the other smooth compensator techniques. Further studies are under investigation to evaluate the robustness of the smooth compensator design.

• OSTI ID: 22462422
• Journal Information: Medical Dosimetry, Vol. 40, Issue 1; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0958-3947
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
ANIMAL TISSUES
COMPARATIVE EVALUATIONS
DEPTH
DESIGN
PATIENTS
PLANNING
PROTON BEAMS
PROTONS
RADIATION DOSES
RADIOTHERAPY
YIELDS