title: On voxel-by-voxel accumulated dose for prostate radiation therapy using deformable image registration.
abstract: Since delivered dose is rarely the same with planned, we calculated the delivered total dose to ten prostate radiotherapy patients treated with rectal balloons using deformable dose accumulation (DDA) and compared it with the planned dose. The patients were treated with TomoTherapy using two rectal balloon designs: five patients had the Radiadyne balloon (balloon A), and five patients had the EZ-EM balloon (balloon B). Prostate and rectal wall contours were outlined on each pre-treatment MVCT for all patients. Delivered fractional doses were calculated using the MVCT taken immediately prior to delivery. Dose grids were accumulated to the last MVCT using DDA tools in Pinnacle3 TM (v9.100, Philips Radiation Oncology Systems, Fitchburg, USA). Delivered total doses were compared with planned doses using prostate and rectal wall DVHs. The rectal NTCP was calculated based on total delivered and planned doses for all patients using the Lyman model. For 8/10 patients, the rectal wall NTCP calculated using the delivered total dose was less than planned, with seven patients showing a decrease of more than 5% in NTCP. For 2/10 patients studied, the rectal wall NTCP calculated using total delivered dose was 2% higher than planned. This study indicates that for patients receiving hypofractionated radiotherapy for prostate cancer with a rectal balloon, total delivered doses to prostate is similar with planned while delivered dose to rectal walls may be significantly different from planned doses. 8/10 patients show significant correlation between rectal balloon anterior-posterior positions and some VD values.
authors.affiliation: Department of Human Oncology and Medical Physics, University of Wisconsin-Madison, USA Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Jialu
authors.initials: J
authors.lastname: Yu
authors.affiliation: Department of Human Oncology and Medical Physics, University of Wisconsin-Madison, USA Department of Physical Sciences, Peter MacCallum Cancer Centre, Australia Center for Medical Radiation Physics, University of Wollongong, Australia.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Hardcastle
authors.affiliation: Department of Human Oncology and Medical Physics, University of Wisconsin-Madison, USA Department of Radiation Oncology, Montefiore Medical Center and Institute for Onco-Physics, Albert Einstein College of Medicine, Bronx, NY.
authors.forename: Kyoungkeun
authors.initials: K
authors.lastname: Jeong
authors.affiliation: Department of Human Oncology and Medical Physics, University of Wisconsin-Madison, USA.
authors.forename: Edward T
authors.initials: ET
authors.lastname: Bender
authors.affiliation: Department of Human Oncology and Medical Physics, University of Wisconsin-Madison, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Ritter
authors.affiliation: Department of Human Oncology and Medical Physics, University of Wisconsin-Madison, USA Center for Medical Radiation Physics, University of Wollongong, Australia Department of Radiation Oncology, Montefiore Medical Center and Institute for Onco-Physics, Albert Einstein College of Medicine, Bronx, NY wolfgang.tome@einstein.yu.edu.
authors.forename: Wolfgang A
authors.initials: WA
authors.lastname: Tomé
mesh_terms: D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D061089:Radiotherapy, Image-Guided / Q000379:methods; D036542:Tomography, Spiral Computed
keywords: DIR; Deformable dose accumulation; Planned versus delivered NTCP.; Planned versus delivered TCP; gEUD