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Development of a novel low-radiation-absorbent lok-bar to reduce X-ray scattering and absorption in RapidArc® treatment planning and dose delivery.
J Appl Clin Med Phys 2017; 18(3):44-51JA

Abstract

We developed a novel low-radiation-absorbent lok-bar (HM-bar) that is used to secure the immobilizers to the couch. The aim of this study was to investigate the X-ray scattering and absorption properties of the HM-bar in computed tomography (CT) simulation and radiotherapy dose delivery using the Varian Exact™ lok-bar (VL-bar) as a benchmark. CT images were obtained with or without lok-bar, and then each image was visually evaluated for artifacts. The attenuation rates for each lok-bar were measured using a farmer-type ionization chamber (PTW30013) and the I'mRT phantom (IBA Dosimetry GmbH). Measurement points were between gantry angles of 110 and 180°. The treatment apparatus was a NovalisTx (Brainlab AG); X-ray energies were set at 6 MV and 10 MV. In the presence of each lok-bar, the radiation dose was measured in accordance with 10 volumetric modulated arc therapy-stereotactic body radiation therapy (VMAT-SBRT) plans for lung cancer. Artifacts were seldom observed in the CT scans of the HM-bar. The attenuation rate of each lok-bar was higher when the X-ray energy was set at 6 MV than at 10 MV. The highest attenuation rate in the VL-bar was observed at a gantry angle of 112°; the rates were 22.4% at 6 MV and 19.3% at 10 MV. Similarly, the highest attenuation rate for the HM-bar was also observed at a gantry angle of 112°; the rates were 12.2% and 10.1% at 6 MV and 10 MV, respectively. When the VL-bar was evaluated, the isocenter dose of the VMAT-SBRT plans was attenuated by 2.6% as a maximum case. In the case of the HM-bar, the maximum attenuation was 1.4%. In the measurements of each VMAT-SBRT plan, the difference of the dose attenuation rate between the VL-bar and HM-bar was approximately 1%. The HM-bar could be used to minimize the occurrence of artifacts and provide good images in CT scans regarding radiotherapy planning and dose calculation. It can be used for patient therapy at hospitals to provide accurate dose delivery because of its low X-ray scattering and absorption characteristics.

Authors+Show Affiliations

Department of Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama-shi, Osaka, 589-8511, Japan.Department of Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama-shi, Osaka, 589-8511, Japan.Department of Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama-shi, Osaka, 589-8511, Japan.Business Planning Department, Toppan Printing Co. Ltd, 1-5-1 Taito, Taito-ku, Tokyo, 110-8560, Japan.Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama-shi, Osaka, 589-8511, Japan.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

28383157

Citation

Monzen, Hajime, et al. "Development of a Novel Low-radiation-absorbent Lok-bar to Reduce X-ray Scattering and Absorption in RapidArc® Treatment Planning and Dose Delivery." Journal of Applied Clinical Medical Physics, vol. 18, no. 3, 2017, pp. 44-51.
Monzen H, Kubo K, Tamura M, et al. Development of a novel low-radiation-absorbent lok-bar to reduce X-ray scattering and absorption in RapidArc® treatment planning and dose delivery. J Appl Clin Med Phys. 2017;18(3):44-51.
Monzen, H., Kubo, K., Tamura, M., Hayakawa, M., & Nishimura, Y. (2017). Development of a novel low-radiation-absorbent lok-bar to reduce X-ray scattering and absorption in RapidArc® treatment planning and dose delivery. Journal of Applied Clinical Medical Physics, 18(3), pp. 44-51. doi:10.1002/acm2.12066.
Monzen H, et al. Development of a Novel Low-radiation-absorbent Lok-bar to Reduce X-ray Scattering and Absorption in RapidArc® Treatment Planning and Dose Delivery. J Appl Clin Med Phys. 2017;18(3):44-51. PubMed PMID: 28383157.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Development of a novel low-radiation-absorbent lok-bar to reduce X-ray scattering and absorption in RapidArc® treatment planning and dose delivery. AU - Monzen,Hajime, AU - Kubo,Kazuki, AU - Tamura,Mikoto, AU - Hayakawa,Masaru, AU - Nishimura,Yasumasa, Y1 - 2017/04/06/ PY - 2016/08/03/received PY - 2016/11/08/revised PY - 2017/01/25/accepted PY - 2017/4/7/pubmed PY - 2018/3/31/medline PY - 2017/4/7/entrez KW - artifacts KW - immobilizer KW - lok-bar KW - stereotactic body radiation therapy KW - volumetric modulated arc therapy SP - 44 EP - 51 JF - Journal of applied clinical medical physics JO - J Appl Clin Med Phys VL - 18 IS - 3 N2 - We developed a novel low-radiation-absorbent lok-bar (HM-bar) that is used to secure the immobilizers to the couch. The aim of this study was to investigate the X-ray scattering and absorption properties of the HM-bar in computed tomography (CT) simulation and radiotherapy dose delivery using the Varian Exact™ lok-bar (VL-bar) as a benchmark. CT images were obtained with or without lok-bar, and then each image was visually evaluated for artifacts. The attenuation rates for each lok-bar were measured using a farmer-type ionization chamber (PTW30013) and the I'mRT phantom (IBA Dosimetry GmbH). Measurement points were between gantry angles of 110 and 180°. The treatment apparatus was a NovalisTx (Brainlab AG); X-ray energies were set at 6 MV and 10 MV. In the presence of each lok-bar, the radiation dose was measured in accordance with 10 volumetric modulated arc therapy-stereotactic body radiation therapy (VMAT-SBRT) plans for lung cancer. Artifacts were seldom observed in the CT scans of the HM-bar. The attenuation rate of each lok-bar was higher when the X-ray energy was set at 6 MV than at 10 MV. The highest attenuation rate in the VL-bar was observed at a gantry angle of 112°; the rates were 22.4% at 6 MV and 19.3% at 10 MV. Similarly, the highest attenuation rate for the HM-bar was also observed at a gantry angle of 112°; the rates were 12.2% and 10.1% at 6 MV and 10 MV, respectively. When the VL-bar was evaluated, the isocenter dose of the VMAT-SBRT plans was attenuated by 2.6% as a maximum case. In the case of the HM-bar, the maximum attenuation was 1.4%. In the measurements of each VMAT-SBRT plan, the difference of the dose attenuation rate between the VL-bar and HM-bar was approximately 1%. The HM-bar could be used to minimize the occurrence of artifacts and provide good images in CT scans regarding radiotherapy planning and dose calculation. It can be used for patient therapy at hospitals to provide accurate dose delivery because of its low X-ray scattering and absorption characteristics. SN - 1526-9914 UR - https://www.unboundmedicine.com/medline/citation/28383157/Development_of_a_novel_low_radiation_absorbent_lok_bar_to_reduce_X_ray_scattering_and_absorption_in_RapidArc®_treatment_planning_and_dose_delivery_ L2 - https://doi.org/10.1002/acm2.12066 DB - PRIME DP - Unbound Medicine ER -