SBRT focal dose intensification using an MR-Linac adaptive planning for intermediate-risk prostate cancer: An analysis of the dosimetric impact of intra-fractional organ changes Journal Article
| Authors: | Brennan, V. S.; Burleson, S.; Kostrzewa, C.; Godoy Scripes, P.; Subashi, E.; Zhang, Z.; Tyagi, N.; Zelefsky, M. J. |
| Article Title: | SBRT focal dose intensification using an MR-Linac adaptive planning for intermediate-risk prostate cancer: An analysis of the dosimetric impact of intra-fractional organ changes |
| Abstract: | Introduction: Using an magnetic resonance linear accelerator (MR-Linac) may improve the precision of visible tumor boosting with ultra-hypofractionation by accounting for daily positional changes in the target and organs at risk (OAR). Patients and methods: Fifteen patients with prostate cancer and an MR-detected dominant lesion were treated on the MR-Linac with stereotactic body radiation (SBRT) to 40 Gy in 5 fractions, boosting the gross tumor volume (GTV) to 45 Gy with daily adaptive planning. Imaging was acquired again after initial planning (verification scan), and immediately after treatment (post-treatment scan). Prior to beam-on, additional adjustments were made on the verification scan. Contours were retrospectively adjusted on verification and post-treatment scans, and the daily plan recalculated on these scans to estimate the true dose delivered. Results: The median prostate D95% for plan 1, 2 and 3 was 40.3 Gy, 40.5 Gy and 40.3 Gy and DIL D95% was 45.7 Gy, 45.2 Gy and 44.6 Gy, respectively. Bladder filling was associated with reduced GTV coverage (p = 0.03, plan 1 vs 2) and prostate coverage (p = 0.03, plan 2 vs 3). The D0.035 cc constraint was exceeded on verification and post-treatment plans in 24 % and 33 % of fractions for the urethra, 31 % and 45 % for the bladder, and 35 % and 25 % for the rectum, respectively. Conclusion: MR-Linac guided, daily adaptive SBRT with focal boosting of the GTV yields acceptable planned and delivered dosimetry. Adaptive planning with a MR-Linac may reliably deliver the prescribed dose to the intended tumor target. © 2022 |
| Keywords: | adult; clinical article; controlled study; treatment planning; cancer patient; cancer radiotherapy; nuclear magnetic resonance imaging; prostate cancer; whole body radiation; stereotactic body radiation therapy; androgen deprivation therapy; nuclear magnetic resonance; sbrt; gross tumor volume; clinical target volume; intrafractional motion; organs at risk; bladder capacity; Common Terminology Criteria for Adverse Events; planning target volume; hypofractionated radiotherapy; drug dose intensification; human; male; article; radiation oncologist; treatment interruption; adaptive planning; mr-linac; bladder filling; focal boosting |
| Journal Title: | Radiotherapy and Oncology |
| Volume: | 179 |
| ISSN: | 0167-8140 |
| Publisher: | Elsevier Inc. |
| Date Published: | 2023-02-01 |
| Start Page: | 109441 |
| Language: | English |
| DOI: | 10.1016/j.radonc.2022.109441 |
| PUBMED: | 36549340 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | Article -- MSK corresponding authors are Victoria Sarah Brennan and Caroline Kostrzewa -- Export Date: 1 February 2023 -- Source: Scopus |
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