Image Guidance Based on Prostate Position for Prostate Cancer Proton Therapy

Journal Article · Fri Aug 01 00:00:00 EDT 2008 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2007.12.016· OSTI ID:21124384

Vargas, Carlos ^[1]; Wagner, Marcus ^[1]; Indelicato, Daniel ^[2]; Fryer, Amber; Horne, David; Chellini, Angela; McKenzie, Craig; Lawlor, Paula; Mahajan, Chaitali; Zuofeng, Li; Liyong, Lin; Keole, Sameer ^[1]

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1. University of Florida Proton Therapy Institute, Jacksonville, FL (United States)
2. Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL (United States)

Purpose: To determine the target coverage for proton therapy with and without image guidance and daily prebeam reorientation. Methods and Materials: A total of 207 prostate positions were analyzed for 9 prostate cancer patients treated using our low-risk prostate proton therapy protocol (University of Florida Proton Therapy Institute 001). The planning target volume was defined as the prostate plus a 5-mm axial and 8-mm superoinferior extension. The prostate was repositioned using 5- and 10-mm shifts (anteriorly, inferiorly, posteriorly, and superiorly) and for Points A-D using a combination of 10-mm multidimensional movements (anteriorly or inferiorly; posteriorly or superiorly; and left or right). The beams were then realigned using the new prostate position. The prescription dose was 78 Gray equivalent (GE) to 95% of the planning target volume. Results: For small movements in the anterior, inferior, and posterior directions within the planning target volume ({<=}5 mm), treatment realignment demonstrated small, but significant, improvements in the clinical target volume (CTV) coverage to the prescribed dose (78 GE). The anterior and posterior shifts also significantly increased the minimal CTV dose ({delta} +1.59 GE). For prostate 10-mm movements in the inferior, posterior, and superior directions, the beam realignment produced larger and significant improvements for both the CTV V{sub 78} ({delta} +6.4%) and the CTV minimal dose ({delta} +8.22 GE). For the compounded 10-mm multidimensional shifts, realignment significantly improved the CTV V{sub 78} ({delta} +11.8%) and CTV minimal dose ({delta} +23.6 GE). After realignment, the CTV minimal dose was >76.6 GE (>98%) for all points (A-D). Conclusion: Proton beam realignment after target shift will enhance CTV coverage for different prostate positions.

• OSTI ID: 21124384
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Vol. 71, Issue 5; Other Information: DOI: 10.1016/j.ijrobp.2007.12.016; PII: S0360-3016(07)04708-6; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CARCINOMAS
IMAGES
PLANNING
PROSTATE
PROTON BEAMS
RADIATION DOSES
RADIOTHERAPY