SU‐FF‐T‐80: Hybrid Image Guided Radiation Therapy for Hypofractionated Prostate IMRT: Feasibility Study

• Published in: Medical Physics 2009-06, Vol.36 (6), p.2537-2538
• Main Authors: Thongphiew, D, Zhu, X, Wu, Q, Yin, F
• Format: Article
• Language: English
• Subjects: Computed tomography; Cone beam computed tomography; Dosimetry; Image guided radiation therapy; Intensity modulated radiation therapy; Vesicles
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.3181553

Purpose: In prostate IGRT employing hypofractionation, two methods are commonly used: patient re‐positioning and re‐planning. We propose a hybrid IGRT technique in this study. The dosimetric benefits and efficiency improvement of the technique is quantitatively evaluated by comparing with the two conventional techniques. Method and Materials: Five prostate patients were studied, each had 1 planning CT and 11 daily CBCTs. The structure‐of‐interest (SOIs) including CTV (prostate and seminal vesicles), bladder, and rectum were contoured on CT and CBCTs. Initial IMRT plans were generated on Eclipse. Three IGRT techniques (“re‐positioning”, “re‐plan”, and “hybrid”) were applied on each CBCT. “Re‐positioning” utilizes target soft‐tissue matching for patient position correction. “Re‐plan” re‐aligns the patient then reoptimizes the original plan using daily SOIs. “Hybrid” first finds the best‐fit plan from plan‐library for the daily CBCT. If no suitable plan found, “re‐plan” is performed and new plan is added to library. The daily and cumulative doses were calculated and compared for all three techniques. Results: (1) Cumulative dose: For CTV and bladder, the difference among the three IGRT techniques are