Dana J Lewis1,2,3, Paige A Taylor1,2,3, David S Followill1,2,3, Narayan Sahoo2,3, Anita Mahajan3,4, Francesco C Stingo3,5, Stephen F Kry1,2,3. 1. Imaging and Radiation Oncology Core Quality Assurance Office, Houston, TX, USA. 2. Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA. 3. The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston TX, USA. 4. Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA. 5. Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Abstract
PURPOSE: To design and evaluate an anthropomorphic spine phantom for use in credentialing proton therapy facilities for clinical trial participation by the Imaging and Radiation Oncology Core Houston QA Center. MATERIALS AND METHODS: A phantom was designed to perform an end-to-end audit of the proton spine treatment process, including simulation, dose calculation, and proton treatment delivery. Because plastics that simulate bone in proton beams are unknown, 11 potential materials were tested to identify suitable phantom materials. Once built, preliminary testing using passive scattering and spot scanning treatment plans (including a field junction) were created in-house and delivered 3 times to test reproducibility. The following measured attributes were compared with the calculated values: absolute dose agreement using thermoluminescent dosimeters, planar gamma agreement, distal range, junction match, and right and left profile alignment using radiochromic film. Finally, credentialing results from 10 institutions were also assessed. RESULTS: A suitable bone substitute was identified (Techtron HPV Bearing Grade), which had a measured relative stopping power that agreed within 1.1% of its value calculated by Eclipse. In-house passive scatter testing of the phantom demonstrated that the phantom was suitable for assessing craniospinal irradiation dose delivery. However, the in-house scanning beam results were more mixed, highlighting challenges in treatment delivery. Seven of ten institutions passed the proposed criteria for this phantom, a pass rate consistent with other Imaging and Radiation Oncology phantoms. CONCLUSIONS: An anthropomorphic proton spine phantom was developed to evaluate proton therapy delivery. This phantom provides a realistic challenge for centers wishing to participate in proton clinical trials and highlights the need for caution in applying advanced treatments.
PURPOSE: To design and evaluate an anthropomorphic spine phantom for use in credentialing proton therapy facilities for clinical trial participation by the Imaging and Radiation Oncology Core Houston QA Center. MATERIALS AND METHODS: A phantom was designed to perform an end-to-end audit of the proton spine treatment process, including simulation, dose calculation, and proton treatment delivery. Because plastics that simulate bone in proton beams are unknown, 11 potential materials were tested to identify suitable phantom materials. Once built, preliminary testing using passive scattering and spot scanning treatment plans (including a field junction) were created in-house and delivered 3 times to test reproducibility. The following measured attributes were compared with the calculated values: absolute dose agreement using thermoluminescent dosimeters, planar gamma agreement, distal range, junction match, and right and left profile alignment using radiochromic film. Finally, credentialing results from 10 institutions were also assessed. RESULTS: A suitable bone substitute was identified (Techtron HPV Bearing Grade), which had a measured relative stopping power that agreed within 1.1% of its value calculated by Eclipse. In-house passive scatter testing of the phantom demonstrated that the phantom was suitable for assessing craniospinal irradiation dose delivery. However, the in-house scanning beam results were more mixed, highlighting challenges in treatment delivery. Seven of ten institutions passed the proposed criteria for this phantom, a pass rate consistent with other Imaging and Radiation Oncology phantoms. CONCLUSIONS: An anthropomorphic proton spine phantom was developed to evaluate proton therapy delivery. This phantom provides a realistic challenge for centers wishing to participate in proton clinical trials and highlights the need for caution in applying advanced treatments.
Authors: Paige A Taylor; Stephen F Kry; Paola Alvarez; Tyler Keith; Carrie Lujano; Nadia Hernandez; David S Followill Journal: Int J Radiat Oncol Biol Phys Date: 2016-02-10 Impact factor: 7.038
Authors: Rebecca M Howell; Annelise Giebeler; Wendi Koontz-Raisig; Anita Mahajan; Carol J Etzel; Anthony M D'Amelio; Kenneth L Homann; Wayne D Newhauser Journal: Radiat Oncol Date: 2012-07-24 Impact factor: 3.481
Authors: Ryan L Grant; Paige A Summers; James L Neihart; Anthony P Blatnica; Narayan Sahoo; Michael T Gillin; David S Followill; Geoffrey S Ibbott Journal: J Appl Clin Med Phys Date: 2014-03-06 Impact factor: 2.102
Authors: Paige A Taylor; Jessica Lowenstein; David Followill; Stephen F Kry Journal: Int J Radiat Oncol Biol Phys Date: 2021-11-13 Impact factor: 7.038