{"title":"考虑立体定向放射外科治疗时间的脑转移瘤放射生物学评价","authors":"Hisashi Nakano, Takeshi Takizawa, Daisuke Kawahara, Satoshi Tanabe, Satoru Utsunomiya, Motoki Kaidu, Katsuya Maruyama, Shigekazu Takeuchi, Kiyoshi Onda, Masahiko Koizumi, Teiji Nishio, Hiroyuki Ishikawa","doi":"10.1259/bjro.20220013","DOIUrl":null,"url":null,"abstract":"<p><strong>Objective: </strong>We evaluated the radiobiological effect of the irradiation time with the interruption time of stereotactic radiosurgery (SRS) using CyberKnife<sup>®</sup> (CK) systemfor brain metastases.</p><p><strong>Methods: </strong>We used the DICOM data and irradiation log file of the 10 patients with brain metastases from non-small-cell lung cancer (NSCLC) who underwent brain SRS. We defined the treatment time as the sum of the dose-delivery time and the interruption time during irradiations, and we used a microdosimetric kinetic model (MKM) to evaluate the radiobiological effects of the treatment time. The biological parameters, <i>i.e.</i> α<sub>0</sub>, β<sub>0</sub>, and the DNA repair constant rate (<i>a</i> + c), were acquired from NCI-H460 cell for the MKM. We calculated the radiobiological dose for the gross tumor volume (GTV<sub>bio</sub>) to evaluate the treatment time's effect compared with no treatment time as a reference. The D95 (%) and the Radiation Therapy Oncology Group conformity index (RCI) and Paddick conformity index (PCI) were calculated as dosimetric indices. We used several DNA repair constant rates (<i>a</i> + c) (0.46, 1.0, and 2.0) to assess the radiobiological effect by varying the DNA repair date (<i>a</i> + c) values.</p><p><strong>Results: </strong>The mean values of D95 (%), RCI, and PCI for GTV<sub>bio</sub> were 98.8%, 0.90, and 0.80, respectively, and decreased with increasing treatment time. The mean values of D95 (%), RCI, and PCI of GTV<sub>bio</sub> at 2.0 (a+c) value were 94.9%, 0.71, and 0.49, respectively.</p><p><strong>Conclusion: </strong>The radiobiological effect of the treatment time on tumors was accurately evaluated with brain SRS using CK.</p><p><strong>Advances in knowledge: </strong>There has been no published investigation of the radiobiological impact of the longer treatment time with multiple interruptions of SRS using a CK on the target dose distribution in a comparison with the use of a linac. Radiobiological dose assessment that takes into account treatment time in the physical dose in this study may allow more accurate dose assessment in SRS for metastatic brain tumors using CK.</p>","PeriodicalId":72419,"journal":{"name":"BJR open","volume":" ","pages":"20220013"},"PeriodicalIF":0.0000,"publicationDate":"2022-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10958663/pdf/","citationCount":"0","resultStr":"{\"title\":\"Radiobiological evaluation considering the treatment time with stereotactic radiosurgery for brain metastases.\",\"authors\":\"Hisashi Nakano, Takeshi Takizawa, Daisuke Kawahara, Satoshi Tanabe, Satoru Utsunomiya, Motoki Kaidu, Katsuya Maruyama, Shigekazu Takeuchi, Kiyoshi Onda, Masahiko Koizumi, Teiji Nishio, Hiroyuki Ishikawa\",\"doi\":\"10.1259/bjro.20220013\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><strong>Objective: </strong>We evaluated the radiobiological effect of the irradiation time with the interruption time of stereotactic radiosurgery (SRS) using CyberKnife<sup>®</sup> (CK) systemfor brain metastases.</p><p><strong>Methods: </strong>We used the DICOM data and irradiation log file of the 10 patients with brain metastases from non-small-cell lung cancer (NSCLC) who underwent brain SRS. We defined the treatment time as the sum of the dose-delivery time and the interruption time during irradiations, and we used a microdosimetric kinetic model (MKM) to evaluate the radiobiological effects of the treatment time. The biological parameters, <i>i.e.</i> α<sub>0</sub>, β<sub>0</sub>, and the DNA repair constant rate (<i>a</i> + c), were acquired from NCI-H460 cell for the MKM. We calculated the radiobiological dose for the gross tumor volume (GTV<sub>bio</sub>) to evaluate the treatment time's effect compared with no treatment time as a reference. The D95 (%) and the Radiation Therapy Oncology Group conformity index (RCI) and Paddick conformity index (PCI) were calculated as dosimetric indices. We used several DNA repair constant rates (<i>a</i> + c) (0.46, 1.0, and 2.0) to assess the radiobiological effect by varying the DNA repair date (<i>a</i> + c) values.</p><p><strong>Results: </strong>The mean values of D95 (%), RCI, and PCI for GTV<sub>bio</sub> were 98.8%, 0.90, and 0.80, respectively, and decreased with increasing treatment time. The mean values of D95 (%), RCI, and PCI of GTV<sub>bio</sub> at 2.0 (a+c) value were 94.9%, 0.71, and 0.49, respectively.</p><p><strong>Conclusion: </strong>The radiobiological effect of the treatment time on tumors was accurately evaluated with brain SRS using CK.</p><p><strong>Advances in knowledge: </strong>There has been no published investigation of the radiobiological impact of the longer treatment time with multiple interruptions of SRS using a CK on the target dose distribution in a comparison with the use of a linac. Radiobiological dose assessment that takes into account treatment time in the physical dose in this study may allow more accurate dose assessment in SRS for metastatic brain tumors using CK.</p>\",\"PeriodicalId\":72419,\"journal\":{\"name\":\"BJR open\",\"volume\":\" \",\"pages\":\"20220013\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2022-11-24\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10958663/pdf/\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"BJR open\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1259/bjro.20220013\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"2022/1/1 0:00:00\",\"PubModel\":\"eCollection\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"BJR open","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1259/bjro.20220013","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2022/1/1 0:00:00","PubModel":"eCollection","JCR":"","JCRName":"","Score":null,"Total":0}
Radiobiological evaluation considering the treatment time with stereotactic radiosurgery for brain metastases.
Objective: We evaluated the radiobiological effect of the irradiation time with the interruption time of stereotactic radiosurgery (SRS) using CyberKnife® (CK) systemfor brain metastases.
Methods: We used the DICOM data and irradiation log file of the 10 patients with brain metastases from non-small-cell lung cancer (NSCLC) who underwent brain SRS. We defined the treatment time as the sum of the dose-delivery time and the interruption time during irradiations, and we used a microdosimetric kinetic model (MKM) to evaluate the radiobiological effects of the treatment time. The biological parameters, i.e. α0, β0, and the DNA repair constant rate (a + c), were acquired from NCI-H460 cell for the MKM. We calculated the radiobiological dose for the gross tumor volume (GTVbio) to evaluate the treatment time's effect compared with no treatment time as a reference. The D95 (%) and the Radiation Therapy Oncology Group conformity index (RCI) and Paddick conformity index (PCI) were calculated as dosimetric indices. We used several DNA repair constant rates (a + c) (0.46, 1.0, and 2.0) to assess the radiobiological effect by varying the DNA repair date (a + c) values.
Results: The mean values of D95 (%), RCI, and PCI for GTVbio were 98.8%, 0.90, and 0.80, respectively, and decreased with increasing treatment time. The mean values of D95 (%), RCI, and PCI of GTVbio at 2.0 (a+c) value were 94.9%, 0.71, and 0.49, respectively.
Conclusion: The radiobiological effect of the treatment time on tumors was accurately evaluated with brain SRS using CK.
Advances in knowledge: There has been no published investigation of the radiobiological impact of the longer treatment time with multiple interruptions of SRS using a CK on the target dose distribution in a comparison with the use of a linac. Radiobiological dose assessment that takes into account treatment time in the physical dose in this study may allow more accurate dose assessment in SRS for metastatic brain tumors using CK.
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