A class solution for volumetric-modulated arc therapy planning in postprostatectomy radiotherapy

Elizabeth Forde; Regina Bromley; Andrew Kneebone; Thomas Eade

doi:10.1016/j.meddos.2014.04.002

A class solution for volumetric-modulated arc therapy planning in postprostatectomy radiotherapy

Med Dosim. 2014 Autumn;39(3):261-5. doi: 10.1016/j.meddos.2014.04.002. Epub 2014 Jun 3.

Authors

Elizabeth Forde¹, Regina Bromley², Andrew Kneebone³, Thomas Eade³

Affiliations

¹ Radiation Oncology Department, Northern Sydney Cancer Centre, St Leonards, New South Wales, Australia. Electronic address: eforde@tcd.ie.
² Radiation Oncology Department, Northern Sydney Cancer Centre, St Leonards, New South Wales, Australia; Institute of Medical Physics, School of Physics, University of Sydney, New South Wales, Australia.
³ Radiation Oncology Department, Northern Sydney Cancer Centre, St Leonards, New South Wales, Australia; Northern Clinical School, University of Sydney, New South Wales, Australia.

PMID: 24933317
DOI: 10.1016/j.meddos.2014.04.002

Abstract

This study is aimed to test a postprostatectomy volumetric-modulated arc therapy (VMAT) planning class solution. The solution applies to both the progressive resolution optimizer algorithm version 2 (PRO 2) and the algorithm version 3 (PRO 3), addressing the effect of an upgraded algorithm. A total of 10 radical postprostatectomy patients received 68 Gy to 95% of the planning target volume (PTV), which was planned using VMAT. Each case followed a set of planning instructions; including contouring, field setup, and predetermined optimization parameters. Each case was run through both algorithms only once, with no user interaction. Results were averaged and compared against Radiation Therapy Oncology Group (RTOG) 0534 end points. In addition, the clinical target volume (CTV) D100, PTV D99, and PTV mean doses were recorded, along with conformity indices (CIs) (95% and 98%) and the homogeneity index. All cases satisfied PTV D95 of 68 Gy and a maximum dose < 74.8 Gy. The average result for the PTV D99 was 64.1 Gy for PRO 2 and 62.1 Gy for PRO 3. The average PTV mean dose for PRO 2 was 71.4 Gy and 71.5 Gy for PRO 3. The CTV D100 average dose was 67.7 and 68.0 Gy for PRO 2 and PRO 3, respectively. The mean homogeneity index for both algorithms was 0.08. The average 95% CI was 1.17 for PRO 2 and 1.19 for PRO 3. For 98%, the average results were 1.08 and 1.12 for PRO 2 and PRO 3, respectively. All cases for each algorithm met the RTOG organs at risk dose constraints. A successful class solution has been established for prostate bed VMAT radiotherapy regardless of the algorithm used.

Keywords: Class solution; Prostatectomy; VMAT.

Publication types

Clinical Trial

MeSH terms

Algorithms
Humans
Male
Prostatectomy
Prostatic Neoplasms / radiotherapy*
Prostatic Neoplasms / surgery
Radiotherapy Planning, Computer-Assisted / methods*
Radiotherapy, Intensity-Modulated*