Linda J Bell1, Thomas Eade2,3, George Hruby2,3, Regina Bromley2, Andrew Kneebone2,3. 1. Northern Sydney Cancer Centre, Radiation Oncology Department, Royal North Shore Hospital, St Leonards, NSW, 2065, Australia. Linda.Bell1@health.nsw.gov.au. 2. Northern Sydney Cancer Centre, Radiation Oncology Department, Royal North Shore Hospital, St Leonards, NSW, 2065, Australia. 3. Northern Clinical School, University of Sydney, St Leonards, NSW, 2065, Australia.
Abstract
BACKGROUND: To measure intra-fraction displacement (IFD) in post-prostatectomy patients treated with anisotropic margins and daily soft tissue matching. METHODS: Pre-treatment cone beam computed tomography (CBCT) scans were acquired daily and post-treatment CBCTs for the first week then weekly on 46 patients. The displacement between the scans was calculated retrospectively to measure IFD of the prostate bed (PB). The marginal miss (MM) rate, and the effect of time between imaging was assessed. RESULTS: A total of 392 post-treatment CBCT's were reviewed from 46 patients. The absolute mean (95% CI) IFD was 1.5 mm (1.3-1.7 mm) in the AP direction, 1.0 mm (0.9-1.2 mm) SI, 0.8 mm (0.7-0.9 mm) LR, and 2.4 mm (2.2-2.5 mm) 3D displacement. IFD ≥ ± 3 mm and ≥ ± 5 mm was 24.7% and 5.4% respectively. MM of the PB was detected in 33 of 392 post-treatment CBCT (8.4%) and lymph nodes in 6 of 211 post-treatment CBCT images (2.8%). Causes of MM due to IFD included changes in the bladder (87.9%), rectum (66.7%) and buttock muscles (6%). A time ≥ 9 min between the pre and post-treatment CBCT demonstrated that movement ≥ 3 mm and 5 mm increased from 19.2 to 40.5% and 5 to 8.1% respectively. CONCLUSIONS: IFD during PB irradiation was typically small, but was a major contributor to an 8.4% MM rate when using daily soft tissue match and tight anisotropic margins.
BACKGROUND: To measure intra-fraction displacement (IFD) in post-prostatectomy patients treated with anisotropic margins and daily soft tissue matching. METHODS: Pre-treatment cone beam computed tomography (CBCT) scans were acquired daily and post-treatment CBCTs for the first week then weekly on 46 patients. The displacement between the scans was calculated retrospectively to measure IFD of the prostate bed (PB). The marginal miss (MM) rate, and the effect of time between imaging was assessed. RESULTS: A total of 392 post-treatment CBCT's were reviewed from 46 patients. The absolute mean (95% CI) IFD was 1.5 mm (1.3-1.7 mm) in the AP direction, 1.0 mm (0.9-1.2 mm) SI, 0.8 mm (0.7-0.9 mm) LR, and 2.4 mm (2.2-2.5 mm) 3D displacement. IFD ≥ ± 3 mm and ≥ ± 5 mm was 24.7% and 5.4% respectively. MM of the PB was detected in 33 of 392 post-treatment CBCT (8.4%) and lymph nodes in 6 of 211 post-treatment CBCT images (2.8%). Causes of MM due to IFD included changes in the bladder (87.9%), rectum (66.7%) and buttock muscles (6%). A time ≥ 9 min between the pre and post-treatment CBCT demonstrated that movement ≥ 3 mm and 5 mm increased from 19.2 to 40.5% and 5 to 8.1% respectively. CONCLUSIONS: IFD during PB irradiation was typically small, but was a major contributor to an 8.4% MM rate when using daily soft tissue match and tight anisotropic margins.
Authors: Linda J Bell; Jennifer Cox; Thomas Eade; Marianne Rinks; Andrew Kneebone Journal: J Med Imaging Radiat Oncol Date: 2013-07-09 Impact factor: 1.735
Authors: Kitty Huang; David A Palma; Danielle Scott; Danielle McGregor; Stewart Gaede; Slav Yartsev; Glenn Bauman; Alexander V Louie; George Rodrigues Journal: Int J Radiat Oncol Biol Phys Date: 2012-02-28 Impact factor: 7.038
Authors: Stephanie Yoon; Minsong Cao; Nima Aghdam; David Shabsovich; Sartajdeep Kahlon; Leslie Ballas; Sean Collins; Michael Lee Steinberg; Amar U Kishan Journal: Radiother Oncol Date: 2020-04-09 Impact factor: 6.280
Authors: Tracy Klayton; Robert Price; Mark K Buyyounouski; Mark Sobczak; Richard Greenberg; Jinsheng Li; Lanea Keller; Dennis Sopka; Alexander Kutikov; Eric M Horwitz Journal: Int J Radiat Oncol Biol Phys Date: 2012-02-11 Impact factor: 7.038
Authors: Linda J Bell; Jennifer Cox; Thomas Eade; Marianne Rinks; Alan Herschtal; Andrew Kneebone Journal: Radiat Oncol Date: 2015-07-26 Impact factor: 3.481