PURPOSE AND BACKGROUND: To study the dosimetric impact of interobserver delineation variability (IODV) in MRI-based cervical cancer brachytherapy. MATERIALS AND METHODS: MR images of six patients were distributed to 10 experienced observers worldwide. They were asked to delineate the target volumes and the organs at risk (OARs) for each patient. Two types of reference contours were created (Expert Consensus - EC and Simultaneous Truth and Performance Level Estimation - STAPLE). Optimised plans based on both EC- and STAPLE-contours were prepared. These plans were transferred to each of the observer contour sets and the resulting DVH parameters (D(90) and D(2cc)) were calculated. For each patient the standard deviation (SD) for the 10 observers was calculated. RESULTS: A mean relative SD of 8-10% was found for GTV and High Risk CTV (HR-CTV) D(90) analysing one single fraction. For rectum and bladder the mean relative SD for D(2cc) was 5-8% while sigmoid was at 11%. For the whole treatment the IODV in HR-CTV caused an uncertainty of ±5 Gy(α/β=10) (1SD). The corresponding figure for OARs was ±2-3 Gy(α/β=3). The results were not sensitive as to which structure set was used for the optimisation. CONCLUSIONS: For the target volumes the dosimetric impact of IODV was smallest for the GTV and HR-CTV, while IODV had an even smaller impact on the bladder and rectum.
PURPOSE AND BACKGROUND: To study the dosimetric impact of interobserver delineation variability (IODV) in MRI-based cervical cancer brachytherapy. MATERIALS AND METHODS: MR images of six patients were distributed to 10 experienced observers worldwide. They were asked to delineate the target volumes and the organs at risk (OARs) for each patient. Two types of reference contours were created (Expert Consensus - EC and Simultaneous Truth and Performance Level Estimation - STAPLE). Optimised plans based on both EC- and STAPLE-contours were prepared. These plans were transferred to each of the observer contour sets and the resulting DVH parameters (D(90) and D(2cc)) were calculated. For each patient the standard deviation (SD) for the 10 observers was calculated. RESULTS: A mean relative SD of 8-10% was found for GTV and High Risk CTV (HR-CTV) D(90) analysing one single fraction. For rectum and bladder the mean relative SD for D(2cc) was 5-8% while sigmoid was at 11%. For the whole treatment the IODV in HR-CTV caused an uncertainty of ±5 Gy(α/β=10) (1SD). The corresponding figure for OARs was ±2-3 Gy(α/β=3). The results were not sensitive as to which structure set was used for the optimisation. CONCLUSIONS: For the target volumes the dosimetric impact of IODV was smallest for the GTV and HR-CTV, while IODV had an even smaller impact on the bladder and rectum.
Authors: Antonio L Damato; Kanopkis Townamchai; Michele Albert; Ryan J Bair; Robert A Cormack; Joanne Jang; Arpad Kovacs; Larissa J Lee; Kimberley S Mak; Kristina L Mirabeau-Beale; Kent W Mouw; John G Phillips; Jennifer L Pretz; Andrea L Russo; John H Lewis; Akila N Viswanathan Journal: Int J Radiat Oncol Biol Phys Date: 2014-05-03 Impact factor: 7.038
Authors: Akila N Viswanathan; Beth Erickson; David K Gaffney; Sushil Beriwal; Sudershan K Bhatia; Omer Lee Burnett; David P D'Souza; Nikhilesh Patil; Michael G Haddock; Anuja Jhingran; Ellen L Jones; Charles A Kunos; Larissa J Lee; Lilie L Lin; Nina A Mayr; Ivy Petersen; Primoz Petric; Lorraine Portelance; William Small; Jonathan B Strauss; Kanokpis Townamchai; Aaron H Wolfson; Catheryn M Yashar; Walter Bosch Journal: Int J Radiat Oncol Biol Phys Date: 2014-10-01 Impact factor: 7.038