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[Development of Novel Immobilization Adapter for Head and Neck Radiotherapy with Low-attenuation Material].

Abstract

PURPOSE

The dosimetric error due to immobilization devices has been highlighted by the AAPM Task Group 176. We developed a novel low-radiation-absorbent immobilization adaptor (HMA), which can be used with a Styrofoam headrest for head and neck region in radiotherapy. The purpose of this study was to investigate the impact of the HMA on the dose distribution and compare with a commercially released plastic adapter.

METHODS

Computed tomography (CT) simulation and dose calculation on a treatment planning system (TPS) were performed by the use of HMA and the plastic adapter with a cylindrical phantom. Both the adapters were placed on the phantom upside and the attenuation rate was measured. Gantry angles were changed at every 1°interval from 0°to 50°for measurements. The measured dose was normalized by the value of 90°. The treatment equipment was TrueBeam (Varian medical systems); X-ray energies were set on 4, 6 and 10 MV, respectively. The measured attenuation rates were also compared with calculation results of TPS.

RESULTS

The highest differences on attenuation rate of both the adapters were observed at a gantry angle of 32.0°; the differences were 3.0% at 4 MV, 2.7% at 6 MV and 3.0% at 10 MV, respectively, and lower absorption was HMA. TPS calculation results of monitor unit for the HMA were within 1.0% in each energy.

CONCLUSION

The HMA was able to provide absorption dose and calculation errors lower than a commercially released adapter. It can also provide more accurate dose delivery for radiotherapy in head and neck because of the low absorption characteristics.

Authors+Show Affiliations

Department of Radiology, Kindai University Hospital.Department of Radiology, Kindai University Hospital.Kyoto College of Medical Science.Department of Radiology, Kindai University Hospital.Department of Medical Physics, Graduate School of Medical Science, Kindai University.Department of Medical Physics, Graduate School of Medical Science, Kindai University.Toppan Printing Co., Ltd.Department of Radiology, Kindai University Hospital.

Pub Type(s)

Journal Article

Language

jpn

PubMed ID

30787223

Citation

Matsumoto, Kenji, et al. "[Development of Novel Immobilization Adapter for Head and Neck Radiotherapy With Low-attenuation Material]." Nihon Hoshasen Gijutsu Gakkai Zasshi, vol. 75, no. 2, 2019, pp. 167-173.
Matsumoto K, Saika T, Shimomura K, et al. [Development of Novel Immobilization Adapter for Head and Neck Radiotherapy with Low-attenuation Material]. Nihon Hoshasen Gijutsu Gakkai Zasshi. 2019;75(2):167-173.
Matsumoto, K., Saika, T., Shimomura, K., Hanaoka, K., Tamura, M., Monzen, H., ... Okumura, M. (2019). [Development of Novel Immobilization Adapter for Head and Neck Radiotherapy with Low-attenuation Material]. Nihon Hoshasen Gijutsu Gakkai Zasshi, 75(2), pp. 167-173. doi:10.6009/jjrt.2019_JSRT_75.2.167.
Matsumoto K, et al. [Development of Novel Immobilization Adapter for Head and Neck Radiotherapy With Low-attenuation Material]. Nihon Hoshasen Gijutsu Gakkai Zasshi. 2019;75(2):167-173. PubMed PMID: 30787223.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - [Development of Novel Immobilization Adapter for Head and Neck Radiotherapy with Low-attenuation Material]. AU - Matsumoto,Kenji, AU - Saika,Takahiro, AU - Shimomura,Kohei, AU - Hanaoka,Kohei, AU - Tamura,Mikoto, AU - Monzen,Hajime, AU - Hayakawa,Masaru, AU - Okumura,Masahiko, PY - 2019/2/22/entrez PY - 2019/2/23/pubmed PY - 2019/7/13/medline KW - head and neck cancer KW - immobilization device KW - low absorption material SP - 167 EP - 173 JF - Nihon Hoshasen Gijutsu Gakkai zasshi JO - Nihon Hoshasen Gijutsu Gakkai Zasshi VL - 75 IS - 2 N2 - PURPOSE: The dosimetric error due to immobilization devices has been highlighted by the AAPM Task Group 176. We developed a novel low-radiation-absorbent immobilization adaptor (HMA), which can be used with a Styrofoam headrest for head and neck region in radiotherapy. The purpose of this study was to investigate the impact of the HMA on the dose distribution and compare with a commercially released plastic adapter. METHODS: Computed tomography (CT) simulation and dose calculation on a treatment planning system (TPS) were performed by the use of HMA and the plastic adapter with a cylindrical phantom. Both the adapters were placed on the phantom upside and the attenuation rate was measured. Gantry angles were changed at every 1°interval from 0°to 50°for measurements. The measured dose was normalized by the value of 90°. The treatment equipment was TrueBeam (Varian medical systems); X-ray energies were set on 4, 6 and 10 MV, respectively. The measured attenuation rates were also compared with calculation results of TPS. RESULTS: The highest differences on attenuation rate of both the adapters were observed at a gantry angle of 32.0°; the differences were 3.0% at 4 MV, 2.7% at 6 MV and 3.0% at 10 MV, respectively, and lower absorption was HMA. TPS calculation results of monitor unit for the HMA were within 1.0% in each energy. CONCLUSION: The HMA was able to provide absorption dose and calculation errors lower than a commercially released adapter. It can also provide more accurate dose delivery for radiotherapy in head and neck because of the low absorption characteristics. SN - 0369-4305 UR - https://www.unboundmedicine.com/medline/citation/30787223/[Development_of_Novel_Immobilization_Adapter_for_Head_and_Neck_Radiotherapy_with_Low-attenuation_Material] L2 - https://dx.doi.org/10.6009/jjrt.2019_JSRT_75.2.167 DB - PRIME DP - Unbound Medicine ER -