Reproducibility and accuracy of a target motion mitigation technique for dose-escalated prostate stereotactic body radiotherapy
| Autor: | Maria João Cardoso, D. Mateus, Beatriz Nunes, Carlo Greco, V. Louro, Joep Stroom, Sandra Vieira, Ana R. Soares, Oriol Pares, Zvi Fuks, N. Pimentel, Justyna Kociolek |
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| Rok vydání: | 2021 |
| Předmět: |
Male
Foley catheter Normal tissue Radiosurgery 030218 nuclear medicine & medical imaging 03 medical and health sciences Motion 0302 clinical medicine Planned Dose Endorectal balloon Prostate Medicine Humans Radiology Nuclear Medicine and imaging Reproducibility business.industry Radiotherapy Planning Computer-Assisted Prostatic Neoplasms Reproducibility of Results Radiotherapy Dosage Hematology medicine.anatomical_structure Oncology Treatment interruption 030220 oncology & carcinogenesis Radiotherapy Intensity-Modulated business Nuclear medicine Stereotactic body radiotherapy |
| Zdroj: | Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 160 |
| ISSN: | 1879-0887 |
| Popis: | Background and purpose To quantitate the accuracy, reproducibility and prostate motion mitigation efficacy rendered by a target immobilization method used in an intermediate-risk prostate cancer dose-escalated 5×9Gy SBRT study. Material and methods An air-inflated (150 cm3) endorectal balloon and Foley catheter with three electromagnetic beacon transponders (EBT) were used to mitigate and track intra-fractional target motion. A 2 mm margin was used for PTV expansion, reduced to 0 mm at the interface with critical OARs. EBT-detected ≥ 2 mm/5 s motions mandated treatment interruption and target realignment prior to completion of planned dose delivery. Geometrical uncertainties were measured with an in-house ESAPI script. Results Quantitative data were obtained in 886 sessions from 189 patients. Mean PTV dose was 45.8 ± 0.4 Gy (D95 = 40.5 ± 0.4 Gy). A mean of 3.7 ± 1.7 CBCTs were acquired to reach reference position. Mean treatment time was 19.5 ± 12 min, 14.1 ± 11 and 5.4 ± 5.9 min for preparation and treatment delivery, respectively. Target motion of 0, 1–2 and >2 mm/10 min were observed in 59%, 30% and 11% of sessions, respectively. Temporary beam-on hold occurred in 7.4% of sessions, while in 6% a new reference CBCT was required to correct deviations. Hence, all sessions were completed with application of the planned dose. Treatment preparation time > 15 min was significantly associated with the need of a second reference CBCT. Overall systematic and random geometrical errors were in the order of 1 mm. Conclusion The prostate immobilization technique explored here affords excellent accuracy and reproducibility, enabling normal tissue dose sculpting with tight PTV margins. |
| Databáze: | OpenAIRE |
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