BACKGROUND AND PURPOSE: Dose effects of intrafraction motion during prone prostate radiotherapy are unknown. We compared prone and supine treatment using real-time tracking data to model dose coverage. MATERIAL AND METHODS: Electromagnetic tracking data were analyzed for 10 patients treated prone, and 15 treated supine, with IMRT for localized prostate cancer. Plans were generated using 0 mm, 3 mm, and 5mm PTV expansions. Manual beam-hold interventions were applied to reposition the patient when translations exceeded a predetermined threshold. A custom software application (SWIFTER) used intrafraction tracking data acquired during beam-on model delivered prostate dose, by applying rigid body transformations to the prostate structure contoured at simulation within the planned dose cloud. The delivered minimum prostate dose as a percentage of planned dose (Dmin%), and prostate volume covered by the prescription dose as a percentage of the planned volume (VRx%) were compared for prone and supine treatment. RESULTS: Dmin% was reduced for prone treatment for 0 (p=0.02) and 3 mm (p=0.03) PTV margins. VRx% was reduced for prone treatment only for 0mm margins (p=0.002). No significant differences were found using 5 mm margins. CONCLUSIONS: Intrafraction motion has a greater impact on target coverage for prone compared to supine prostate radiotherapy. PTV margins of 3 mm or less correlate with a significant decrease in delivered dose for prone treatment.
BACKGROUND AND PURPOSE: Dose effects of intrafraction motion during prone prostate radiotherapy are unknown. We compared prone and supine treatment using real-time tracking data to model dose coverage. MATERIAL AND METHODS: Electromagnetic tracking data were analyzed for 10 patients treated prone, and 15 treated supine, with IMRT for localized prostate cancer. Plans were generated using 0 mm, 3 mm, and 5mm PTV expansions. Manual beam-hold interventions were applied to reposition the patient when translations exceeded a predetermined threshold. A custom software application (SWIFTER) used intrafraction tracking data acquired during beam-on model delivered prostate dose, by applying rigid body transformations to the prostate structure contoured at simulation within the planned dose cloud. The delivered minimum prostate dose as a percentage of planned dose (Dmin%), and prostate volume covered by the prescription dose as a percentage of the planned volume (VRx%) were compared for prone and supine treatment. RESULTS:Dmin% was reduced for prone treatment for 0 (p=0.02) and 3 mm (p=0.03) PTV margins. VRx% was reduced for prone treatment only for 0mm margins (p=0.002). No significant differences were found using 5 mm margins. CONCLUSIONS: Intrafraction motion has a greater impact on target coverage for prone compared to supine prostate radiotherapy. PTV margins of 3 mm or less correlate with a significant decrease in delivered dose for prone treatment.
Authors: Aart J Nederveen; Uulke A van der Heide; Homan Dehnad; R Jeroen A van Moorselaar; Pieter Hofman; Jan J W Lagendijk Journal: Int J Radiat Oncol Biol Phys Date: 2002-05-01 Impact factor: 7.038
Authors: A V D'Amico; R Whittington; S B Malkowicz; J Fondurulia; M H Chen; I Kaplan; C J Beard; J E Tomaszewski; A A Renshaw; A Wein; C N Coleman Journal: J Clin Oncol Date: 1999-01 Impact factor: 44.544
Authors: L A Dawson; D W Litzenberg; K K Brock; M Sanda; M Sullivan; H M Sandler; J M Balter Journal: Int J Radiat Oncol Biol Phys Date: 2000-09-01 Impact factor: 7.038
Authors: Twyla R Willoughby; Patrick A Kupelian; Jean Pouliot; Katsuto Shinohara; Michelle Aubin; Mack Roach; Lisa L Skrumeda; James M Balter; Dale W Litzenberg; Scott W Hadley; John T Wei; Howard M Sandler Journal: Int J Radiat Oncol Biol Phys Date: 2006-06-01 Impact factor: 7.038
Authors: Alan M Nichol; Kristy K Brock; Gina A Lockwood; Douglas J Moseley; Tara Rosewall; Padraig R Warde; Charles N Catton; David A Jaffray Journal: Int J Radiat Oncol Biol Phys Date: 2006-11-02 Impact factor: 7.038
Authors: Andrew John Bayley; Charles Nicholas Catton; Tara Haycocks; Valerie Kelly; Hamideh Alasti; Robert Bristow; Pamela Catton; Juanita Crook; Mary Krystyna Gospodarowicz; Michael McLean; Michael Milosevic; Pardraig Warde Journal: Radiother Oncol Date: 2004-01 Impact factor: 6.280
Authors: Bin S Teh; John E McGary; Lei Dong; Wei-Yuan Mai; L Steve Carpenter; Hsin H Lu; J Kam Chiu; Shiao Y Woo; Walter H Grant; E Brian Butler Journal: Cancer J Date: 2002 Nov-Dec Impact factor: 3.360