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Despite the development of DOSIRIS™, an eye lens dosimeter, the characteristics of DOSIRIS™ in the area of radiotherapy have not been investigated. The purpose of this study was to evaluate the basic characteristics of the 3‐mm dose equivalent measuring instrument DOSIRIS™ in radiotherapy. Dose linearity and energy dependence were evaluated for the irradiation system based on the calibration method of the monitor dosimeter. The angle dependence was measured by irradiating from a total of 18 directions. Interdevice variation was repeated three times by simultaneously irradiating five dosimeters. The measurement accuracy was based on the absorbed dose measured by the monitor dosimeter of the radiotherapy equipment. Absorbed doses were converted to 3‐mm dose equivalents and compared with DOSIRIS™ measurements. Dose linearity was evaluated using the determination coefficient (R2) R2= 0.9998 and 0.9996 at 6 and 10 MV, respectively. For energy dependence, although the therapeutic photons evaluated in this study had higher energies than in the previous studies and had a continuous spectrum, the response was equivalent to 0.2–1.25 MeV, well below the IEC 62387 limits. The maximum error at all angles was 15% (angle of 140°) and the coefficient of variation at all angles was 4.70%, which satisfies the standard of the thermoluminescent dosimeter measuring instrument. Accuracy of measurement was determined in terms of the measurement errors for DOSIRIS™ (3.2% and 4.3% at 6 and 10 MV, respectively,) using the 3‐mm dose equivalent obtained from the theoretical value as a reference. The DOSIRIS™ measurements met the IEC standard which defines the measurement error of ±30% of the irradiance value in IEC 62387. We found that the characteristics of the 3‐mm dose equivalent dosimeter in a high‐energy radiation satisfy the IEC standards and have the same measurement accuracy as diagnostic areas such as Interventional Radiology. In 2012, the International Commission on Radiological Protection reported in their Publication 118 that the threshold dose of lens exposure has been significantly reduced and that the evaluation of lens exposure dose has emerged as a social issue. The purpose of the present study was to evaluate the basic characteristics of the 3‐mm dose equivalent measuring instrument DOSIRIS™ in radiotherapy.

Coronary artery bypass grafting (CABG) is effective for alleviating ischaemic heart disease; however, its long-term benefits depend on graft patency [1].