Triggered Imaging With Auto Beam Hold and Pre-/Posttreatment CBCT During Prostate SABR: Analysis of Time Efficiency, Target Coverage, and Normal Volume Changes
| Autor: | Zoltán László, Akos Gulyban, Tibor Jenei, Judit Kalincsák, Dániel Gugyerás, Katalin Kisiván, Gergely Antal, Melinda Csima, Csaba Glavak, Ferenc Lakosi |
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| Rok vydání: | 2021 |
| Předmět: |
Male
Cone beam computed tomography medicine.medical_treatment Time efficiency Normal volume Radiosurgery SABR volatility model 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Prostate medicine Humans Radiology Nuclear Medicine and imaging business.industry Radiotherapy Planning Computer-Assisted Prostatic Neoplasms Spiral Cone-Beam Computed Tomography Cone-Beam Computed Tomography Treatment verification Radiation therapy medicine.anatomical_structure Oncology 030220 oncology & carcinogenesis Radiotherapy Intensity-Modulated business Nuclear medicine Beam (structure) |
| Zdroj: | Practical Radiation Oncology. 11:e210-e218 |
| ISSN: | 1879-8500 |
| Popis: | Purpose Our purpose was to investigate time efficiency and target coverage for prostate stereotactic ablative radiation therapy (SABR) using triggered imaging (TI) and auto beam hold. Methods and Materials A total of 20 patients were treated with volumetric modulated arc–based SABR. Treatment verification consisted of pre- and post-radiation therapy cone beam computed tomography (CBCT) with gold marker-based TI every 3 seconds. In case of ≥3 mm (deviation limit) displacement, the treatment was interrupted and imaging-based correction was performed. Beam interruptions, intrafractional shifts, and treatment times were recorded. Prostate, rectum, and bladder were delineated on each CBCT. Target coverage was evaluated by comparing the individual prostate delineations with 98% isodose contour volumes (% of the evaluated volumes exceeding the reference). Both inter- and intrafractional changes of bladder and rectal volumes were assessed. Results The average overall treatment time (±standard deviation) was 18 ± 11 min, with a radiation delivery time of 6 ± 3 min if no intrafractional CBCT acquisitions were necessary (91% of fractions). On average, 1.2 beam interruptions per fraction were required with 0/1 correction in 71% of the fractions. The mean residual 3-dimensional shift was 1.6 mm, exceeding the deviation limit in 8%. In the case of intrafractional CBCT and/or ≥2 corrections the treatment time dramatically increased. The 98% isodose lines did not encompass the prostate in only 8/180 (4%) evaluations in 6 different patients, leading to a loss of D98 between 0.1%-6% as a worst case scenario. The bladder volumes showed significant increases during treatment (P Conclusions Time efficiency of TI + auto beam hold with 3 mm/3 sec threshold during prostate SABR is comparable with competitive techniques, resulting in minimal 3-dimensional residual errors with maintained target coverage. Technical developments are necessary to further reduce radiation delivery time. Use of CBCT allowed full control of rectal volumes, while bladder volumes showed significant increases over time. |
| Databáze: | OpenAIRE |
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