Application of an automated dose accumulation workflow in high-risk prostate cancer - validation and dose-volume analysis between planned and delivered dose

Ashley Ong; Kellie Knight; Vanessa Panettieri; Mathew Dimmock; Jeffrey Kit Loong Tuan; Hong Qi Tan; Zubin Master; Caroline Wright

doi:10.1016/j.meddos.2021.09.004

Application of an automated dose accumulation workflow in high-risk prostate cancer - validation and dose-volume analysis between planned and delivered dose

Med Dosim. 2022;47(1):92-97. doi: 10.1016/j.meddos.2021.09.004. Epub 2021 Nov 2.

Authors

Ashley Ong¹, Kellie Knight², Vanessa Panettieri³, Mathew Dimmock², Jeffrey Kit Loong Tuan⁴, Hong Qi Tan⁴, Zubin Master⁴, Caroline Wright²

Affiliations

¹ National Cancer Centre Singapore, Division of Radiation Oncology, Singapore; Monash University, Department of Medical Imaging and Radiation Sciences, Clayton, Australia. Electronic address: Ashley.ong@monash.edu.
² Monash University, Department of Medical Imaging and Radiation Sciences, Clayton, Australia.
³ Monash University, Department of Medical Imaging and Radiation Sciences, Clayton, Australia; Alfred Hospital, Alfred Health Radiation Oncology, Melbourne, Australia.
⁴ National Cancer Centre Singapore, Division of Radiation Oncology, Singapore.

PMID: 34740517
DOI: 10.1016/j.meddos.2021.09.004

Abstract

Inter-fraction organ variations cause deviations between planned and delivered doses in patients receiving radiotherapy for prostate cancer. This study compared planned (D_P) vs accumulated doses (D_A) obtained from daily cone-beam computed tomography (CBCT) scans in high-risk- prostate cancer with pelvic lymph nodes irradiation. An intensity-based deformable image registration algorithm used to estimate contours for D_A was validated using geometrical agreement between radiation oncologist's and deformable image registration algorithm propagated contours. Spearman rank correlations (r_s) between geometric measures and changes in organ volumes were evaluated for 20 cases. Dose-volume (DV) differences between D_A and D_P were compared (Wilcoxon rank test, p < 0.05). A novel region-of-interest (ROI) method was developed and mean doses were analyzed. Geometrical measures for the prostate and organ-at-risk contours were within clinically acceptable criteria. Inter-group mean (± SD) CBCT volumes for the rectum were larger compared to planning CT (pCT) (51.1 ± 11.3 cm³vs 46.6 ± 16.1 cm³), and were moderately correlated with variations in pCT volumes, rs = 0.663, p < 0.01. Mean rectum DV for D_A was higher at V30-40 Gy and lower at V70-75 Gy, p < 0.05. Mean bladder CBCT volumes were smaller compared to pCT (198.8 ± 55 cm³vs 211.5 ± 89.1 cm³), and was moderately correlated with pCT volumes, rs = 0.789, p < 0.01. Bladder D_A was higher at V30-65 Gy and lower at V70-75 Gy (p < 0.05). For the ROI method, rectum and bladder D_A were lower at 5 to 10 mm (p < 0.01) as compared to D_P, whilst bladder D_A was higher than D_P at 20 to 50 mm (p < 0.01). Generated D_A demonstrated significant differences in organ-at-risk doses as compared to D_P. A well-constructed workflow incorporating a ROI DV-extraction method has been validated in terms of efficiency and accuracy designed for seamless integration in the clinic to guide future plan adaptation.

Keywords: Automated dose accumulation; Cone-beam computed tomography; Deformable image registration; Organ motion; Prostate cancer.

MeSH terms

Cone-Beam Computed Tomography
Humans
Image Processing, Computer-Assisted
Male
Prostatic Neoplasms* / diagnostic imaging
Prostatic Neoplasms* / radiotherapy
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted*
Rectum / diagnostic imaging
Workflow