{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T20:01:16Z","timestamp":1780084876022,"version":"3.54.0"},"reference-count":30,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2025,9,3]],"date-time":"2025-09-03T00:00:00Z","timestamp":1756857600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Once Upon a Time Foundation and Telix Pharmaceuticals"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cancers"],"abstract":"<jats:p>Purpose or Objective: To evaluate the feasibility and clinical utility of integrating sequential PSMA-PET imaging into an offline\u2013online adaptive workflow for response-based dominant intraprostatic lesion (DIL)-boosting high-risk prostate cancer treated with stereotactic ablative radiotherapy (SABR). Materials and Methods: As part of a prospective trial, patients were treated on MR- or CBCT-guided adaptive radiotherapy (ART) systems with prostate\/pelvic node 5-fraction SABR (36.25 Gy\/25 Gy) with DIL boost (50 Gy). Whereas traditional DIL boost volumes delineate full pre-therapy imaging-defined disease (GTVinitial), this study serially refined DIL boost volumes based on treatment response defined by PSMA-PET scans after neoadjuvant androgen deprivation therapy (nADT, GTVmb1) and fraction 3 SABR (GTVmb2). DIL delineation employed PET-PSMA fusion to CT\/MR simulation and was guided by a rule-based %SUVmax threshold approach. Comparisons of GTV volumes and OAR dosimetry were performed between plans using GTVinitial versus GTVmb1\/GTVmb2 for DIL boost, for each of the initial cohorts of five patients from the initially treated cohorts. Results: Five patients treated on MR-Linac (n = 3) or CBCT-based ART (n = 2) were analyzed. Three patients exhibited complete imaging response after nADT, omitting GTVmb boosts. Offline GTVmb refinements based on PSMA-PET were seamlessly integrated into ART workflows without introducing additional treatment time. DIL GTV volumes significantly decreased (p = 0.03) from an initial mean of 11.4 cc (GTVinitial) to 4.1 cc (GTVmb1) and 3.0 cc (GTVmb2). Dosimetric analysis showed meaningful reductions in OAR doses: rectal wall D0.035 cc decreased by up to 12 Gy, while bladder wall D0.035 cc and V18.3 Gy reduced from 52.3 Gy and 52.3 cc (Plan_initial) to 42.9 Gy and 24.9 cc (Plan_mb2), respectively. Urethra doses remained stable, with minor reductions. Sigmoid and femoral head doses remained within acceptable limits. Online adaptation efficiently addressed daily anatomical variations, enabling simulation-free plan re-optimization. Conclusion: PSMA-PET-guided adaptive microboosting for HRPCa SABR is feasible and effective. Standard MR-Linac and CBCT systems offer practical alternatives to BgRT platforms, enabling biology-driven dose personalization and potentially reducing toxicity.<\/jats:p>","DOI":"10.3390\/cancers17172893","type":"journal-article","created":{"date-parts":[[2025,9,3]],"date-time":"2025-09-03T12:07:32Z","timestamp":1756901252000},"page":"2893","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Clinical Implementation of PSMA-PET Guided Tumor Response-Based Boost Adaptation in Online Adaptive Radiotherapy for High-Risk Prostate Cancer"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4123-3807","authenticated-orcid":false,"given":"Ruiqi","family":"Li","sequence":"first","affiliation":[{"name":"Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mu-Han","family":"Lin","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nghi C.","family":"Nguyen","sequence":"additional","affiliation":[{"name":"Department of Nuclear Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fan-Chi","family":"Su","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4466-0647","authenticated-orcid":false,"given":"David","family":"Parsons","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Erica","family":"Salcedo","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elizeva","family":"Phillips","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sean","family":"Domal","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aurelie","family":"Garant","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Raquibul","family":"Hannan","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniel","family":"Yang","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Asim","family":"Afaq","sequence":"additional","affiliation":[{"name":"Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4329-506X","authenticated-orcid":false,"given":"MinJae","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, University of Texas Health Sciences Center Medical School, Houston, TX 77030, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5846-6829","authenticated-orcid":false,"given":"Orhan K.","family":"Oz","sequence":"additional","affiliation":[{"name":"Department of Radiology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6287-3427","authenticated-orcid":false,"given":"Neil","family":"Desai","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX 75235, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1128","DOI":"10.1002\/pros.24041","article-title":"Prostate cancer-specific mortality burden by risk group among men with localized disease: Implications for research and clinical trial priorities","volume":"80","author":"Dee","year":"2020","journal-title":"Prostate"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Spohn, S.K.B., Sachpazidis, I., Wiehle, R., Thomann, B., Sigle, A., Bronsert, P., Ruf, J., Benndorf, M., Nicolay, N.H., and Sprave, T. 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