ABSTRACT
Purpose: To develop a practice-based training strategy to transition from radiation oncologist to therapist-driven prostate MR-Linac adaptive radiotherapy. Methods and materials: In phase 1, 7 therapists independently contoured the prostate and organs-at-risk on T2-weighted MR images from 11 previously treated MR-Linac prostate patients. Contours were evaluated quantitatively (i.e. Dice similarity coefficient [DSC] calculated against oncologist generated online contours) and qualitatively (i.e. oncologist using a 5-point Likert scale; a score ≥ 4 was deemed a pass, a 90% pass rate was required to proceed to the next phase). Phase 2 consisted of supervised online workflow with therapists required no intervention from the oncologist on 10 total cases to advance. Phase 3 involved unsupervised therapist-driven workflow, with offline support from oncologists prior to the next fraction. Results: In phase 1, the mean DSC was 0.92 (range 0.85-0.97), and mean Likert score was 3.7 for the prostate. Five therapists did not attain a pass rate (3-5 cases with prostate contour score < 4), underwent follow-up one-on-one review, and performed contours on a further training set (n = 5). Each participant completed a median of 12 (range 10-13) cases in phase 2; of 82 cases, minor direction were required from the oncologist on 5 regarding target contouring. Radiation oncologists reviewed 179 treatment fractions in phase 3, and deemed 5 cases acceptable but with suggestions for next fraction; all other cases were accepted without suggestions. Conclusion: A training stepwise program was developed and successfully implemented to enable a therapist-driven workflow for online prostate MR-Linac adaptive radiotherapy.
ABSTRACT
BACKGROUND: Evaluate morbidities and "quality" of fiducial marker placement in primary liver tumours (hepatocellular carcinoma [HCC]) for CyberKnife. MATERIALS AND METHODS: Thirty-six HCC with portal vein thrombosis(PVT) were evaluated for "quality" of fiducial placement, placement time, pain score, complications, recovery time and factors influencing placement. RESULTS: One hundred eight fiducials were placed in 36 patients. Fiducial placement radiation oncologist score was "good" in 24(67%), "fair" in 4(11%), and "poor" in 3(8%) patients. Concordance with radiologist score in "poor", "fair", and "good" score was 2/2(100%), 4/5(80%), and 24/27(89%), respectively(p=0.001). Child-Pugh score(p=0.080), performance status(PS) (p=0.014) and accrued during "learning curve"(p=0.013) affected placement score. Mean placement time(p=0.055), recovery time(p=0.025) was longer and higher major complications(p=0.009) with poor PS. Liver segment involved(p=0.484) and the Barcelona Clinic Liver Cancer(BCLC) stage did not influence placement score. "Good" placement score was 30% in first cohort whereas 93% in last cohort(p=0.023). Time for placement was 42.2 and 14.3 minutes, respectively(p=0.069). Post-fiducial pain score 0-1 in 26 patients(72%) and pain score 3-4 was in 2(6%). Five patients (14%) admitted in "day-care"(2 mild pneumothorax, 3 pain). Mortality in 1 patient(3%) admitted for hemothorax. CONCLUSION: Fiducial placement is safe and in experienced hands, "quality" of placement is "good" in majority. Major complications and admission after fiducial placement are rare. Complications, fiducial placement time, recovery time is more during the "learning curve". Poor Child-Pugh score, extensive liver involvement, poor PS have higher probability of complications.
