Effect of setup error in the single‐isocenter technique on stereotactic radiosurgery for multiple brain metastases
| Autor: | Takumi Yamada, Atsushi Ohta, Takeshi Takizawa, Satoshi Tanabe, Hironori Sakai, Satoru Utsunomiya, Motoki Kaidu, Hidefumi Aoyama, Hisashi Nakano, Hirotake Saito, Ryuta Sasamoto, Eisuke Abe, Toshimichi Nakano |
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| Rok vydání: | 2020 |
| Předmět: |
medicine.medical_treatment
stereotactic radiosurgery Dose distribution Radiosurgery multiple brain metastases setup error 030218 nuclear medicine & medical imaging volumetric modulated arc therapy 03 medical and health sciences 0302 clinical medicine medicine Humans Radiation Oncology Physics Six degrees of freedom Radiology Nuclear Medicine and imaging In patient Instrumentation Mathematics Dose delivery Radiation Tumor size Brain Neoplasms business.industry Radiotherapy Planning Computer-Assisted single‐isocenter technique Isocenter Radiotherapy Dosage Ranging 030220 oncology & carcinogenesis single-isocenter technique Nuclear medicine business |
| Zdroj: | Journal of Applied Clinical Medical Physics |
| ISSN: | 1526-9914 |
| DOI: | 10.1002/acm2.13081 |
| Popis: | In conventional stereotactic radiosurgery (SRS), treatment of multiple brain metastases using multiple isocenters is time-consuming resulting in long dose delivery times for patients. A single-isocenter technique has been developed which enables the simultaneous irradiation of multiple targets at one isocenter. This technique requires accurate positioning of the patient to ensure optimal dose coverage. We evaluated the effect of six degrees of freedom (6DoF) setup errors in patient setups on SRS dose distributions for multiple brain metastases using a single-isocenter technique. We used simulated spherical gross tumor volumes (GTVs) with diameters ranging from 1.0 to 3.0 cm. The distance from the isocenter to the target's center was varied from 0 to 15 cm. We created dose distributions so that each target was entirely covered by 100% of the prescribed dose. The target's position vectors were rotated from 0 degrees-2.0 degrees and translated from 0-1.0 mm with respect to the three axes in space. The reduction in dose coverage for the targets for each setup error was calculated and compared with zero setup error. The calculated margins for the GTV necessary to satisfy the tolerance values for loss of GTV coverage of 3% to 10% were defined as coverage-based margins. In addition, the maximum isocenter to target distance for different 6DoF setup errors was calculated to satisfy the tolerance values. The dose coverage reduction and coverage-based margins increased as the target diameter decreased, and the distance and 6DoF setup error increased. An increase in setup error when a single-isocenter technique is used may increase the risk of missing the tumor; this risk increases with increasing distance from the isocenter and decreasing tumor size. |
| Databáze: | OpenAIRE |
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