M Safavi-Naeini1, Z Han1, S Alnaghy1, D Cutajar1, M Petasecca1, M L F Lerch1, D R Franklin2, J Bucci3, M Carrara4, M Zaider5, A B Rosenfeld1. 1. Centre for Medical Radiation Physics, University of Wollongong, Wollongong 2522, Australia. 2. Faculty of Engineering and Information Technology, University of Technology, Sydney 2007, Australia. 3. St George Hospital Cancer Care Centre, Kogarah 2217, Australia. 4. Fondazione IRCCS Istituto Nazionale dei Tumori, Milan 20133, Italy. 5. Memorial Sloan Kettering Cancer Center, New York, New York 10065.
Abstract
PURPOSE: This paper presents initial experimental results from a prototype of high dose rate (HDR) BrachyView, a novel in-body source tracking system for HDR brachytherapy based on a multipinhole tungsten collimator and a high resolution pixellated silicon detector array. The probe and its associated position estimation algorithms are validated and a comprehensive evaluation of the accuracy of its position estimation capabilities is presented. METHODS: The HDR brachytherapy source is moved through a sequence of positions in a prostate phantom, for various displacements in x, y, and z. For each position, multiple image acquisitions are performed, and source positions are reconstructed. Error estimates in each dimension are calculated at each source position and combined to calculate overall positioning errors. Gafchromic film is used to validate the accuracy of source placement within the phantom. RESULTS: More than 90% of evaluated source positions were estimated with an error of less than one millimeter, with the worst-case error being 1.3 mm. Experimental results were in close agreement with previously published Monte Carlo simulation results. CONCLUSIONS: The prototype of HDR BrachyView demonstrates a satisfactory level of accuracy in its source position estimation, and additional improvements are achievable with further refinement of HDR BrachyView's image processing algorithms.
PURPOSE: This paper presents initial experimental results from a prototype of high dose rate (HDR) BrachyView, a novel in-body source tracking system for HDR brachytherapy based on a multipinhole tungsten collimator and a high resolution pixellated silicon detector array. The probe and its associated position estimation algorithms are validated and a comprehensive evaluation of the accuracy of its position estimation capabilities is presented. METHODS: The HDR brachytherapy source is moved through a sequence of positions in a prostate phantom, for various displacements in x, y, and z. For each position, multiple image acquisitions are performed, and source positions are reconstructed. Error estimates in each dimension are calculated at each source position and combined to calculate overall positioning errors. Gafchromic film is used to validate the accuracy of source placement within the phantom. RESULTS: More than 90% of evaluated source positions were estimated with an error of less than one millimeter, with the worst-case error being 1.3 mm. Experimental results were in close agreement with previously published Monte Carlo simulation results. CONCLUSIONS: The prototype of HDR BrachyView demonstrates a satisfactory level of accuracy in its source position estimation, and additional improvements are achievable with further refinement of HDR BrachyView's image processing algorithms.
Authors: Gabriel P Fonseca; Jacob G Johansen; Ryan L Smith; Luc Beaulieu; Sam Beddar; Gustavo Kertzscher; Frank Verhaegen; Kari Tanderup Journal: Phys Imaging Radiat Oncol Date: 2020-09-28