MRI-guided proton therapy planning: accounting for an inline MRI fringe field.
In this study, the impact of realistic inline MRI fringe field on IMPT plan delivery is investigated for a water phantom, liver tumor and prostate cancer differing in target volume, shape, and field configuration using Monte Carlo simulations. A method to correct for the shift of the beam spot positions in the presence of the inline magnetic field is presented. Results show that when not accounting for the effect of the magnetic field on the pencil beam delivery, the spot positions are substantially shifted and the quality of delivered plans is significantly deteriorated leading to dose inhomogeneities and creation of hot and cold spots. However, by correcting the pencil beam delivery, the dose quality of the IMPT plans is restored to a high degree. Nevertheless, adaptation of beam delivery alone is not robust regarding different treatment sites. By fully accounting during plan optimization for the dose distortions caused by the fringe and imaging fields, highly conformal IMPT plans are achieved. These results demonstrate proton pencil beam scanning and treatment planning can be adapted for precise delivery of state-of-the-art IMPT plans in MR-guided proton therapy in the presence of an inline MRI fringe field. PMID: 31509819 [PubMed - as supplied by publisher]
CONCLUSION: The proposed mp-MRI-guided DIL boost using proton radiation therapy is feasible without violating OAR constraints and demonstrates a potential clinical benefit by improving DIL TCP. This retrospective study suggested the use of IMPT-based DIL SIB may represent a strategy to improve tumor control. ADVANCES IN KNOWLEDGE: This study investigated the planning of mp-MRI-guided DIL boost in prostate proton radiation therapy and estimated its clinical impact with respect to TCP and NTCP. PMID: 31904261 [PubMed - as supplied by publisher]
Conclusion: With a dosimetric success rate of 78.5–97.9%, this software may facilitate online adaptive IMPT of prostate cancer using a fast, free and open implementation.
CONCLUSIONS: This work demonstrate the clinical acceptability of substituting MR converted RSP images instead of CT for IMPT planning of prostate cancer. This further translates into higher contouring accuracy along with lesser imaging dose. PMID: 31734604 [PubMed - as supplied by publisher]
ConclusionsProton beam radiotherapy for prostate cancer is feasible with a low rate of acute toxicity and promising late toxicity and effectivity.
Conditions: Low Risk Prostate Cancer; Intermediate Risk Prostate Cancer Interventions: Other: EPIC questionnaire; Radiation: kV x-ray images; Radiation: Conebeam CT Sponsor: EBG MedAustron GmbH Recruiting
Abstract PURPOSE: To report acute and late genitourinary (GU) and gastrointestinal (GI) toxicities associated with post-prostatectomy proton therapy (PT). METHODS: The first 100 consecutive patients from 2010 to 2016 were retrospectively assessed. Baseline characteristics, prospectively graded CTCAE v4.0 toxicities, and patient-reported outcomes were reported. Late outcomes were reported for 79 patients with 3 months minimum follow up. Toxicity-free survival Kaplan-Meier curves were estimated. Logistic regression assessed associations between toxicities and clinical and treatment characteristics (p
This study's purpose is to develop and evaluate an automated method for adaptation of IMPT plans in near real-time to the anatomy of the day. We developed an automated treatment plan adaptation method using (1) a restoration of spot positions (Bragg peaks) by adapting the energies to the new water equivalent path lengths; and (2) a spot addition to fully cover the target of the day, followed by a fast Reference Point Method optimization of the spot weights resulting in a Pareto optimal plan for the daily anatomy. The method was developed and evaluated using 8-10 repeat CT scans of 11 prostate cancer patients, prescrib...