A free-air ionization chamber is used as the primary standard instrument for absolute measurement of air kerma for of X-ray beams. The evaluation of correction factors is a key importance for establishing the standard. Photon-scattering, and diaphragm transmission and scattering were taken into the accounts to reduce some photon phenomena. On the other hand, electron-loss factor which scatter from an electrode were used for electron compensates. In this research, Correction factors were calculated for each mono-energetic photon from 2 to 60 keV for low energy x-rays and 10 to 320 keV for medium energy x-rays by EGS5 code. The calculated corrections from a mono-energetic photon of W/Mo mammography x-rays were compared between effective energy and spectrum method. There is no significant difference between two methods.

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The supplementary comparison of absorbed dose rate in tissue for beta radiation (APMP.RI(I)-S2) was performed with five national metrology institutes in 2013 and 2014. Two commercial thin window ionization chambers were used as transfer instruments and circulated among the participants. Two of the NMIs measured the calibration coefficients of the chambers in reference fields produced from Pm-147, Kr-85 and Sr-90/Y-90, while the other three measured those only in Sr-90/Y-90 beta-particle field. The degree of equivalence for the participants was determined and this comparison verifies the calibration capabilities of the participating laboratories. In addition, most of the results of this comparison are consistent with another international comparison (EUROMET.RI(I)-S2) reported before this work. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Accurate assessment of the radiation absorbed dose delivered to a tumor and different organs is a potentially importance issue in clinical radiotherapy. The aim of this study is to evaluate the effectiveness of the Fricke Xylenol Gel dosimeter (FXG) to the gamma radiation from Co-60. With this aim, the dose response of FXG and its behavior have been investigated. The sensitivity and accuracy of FXG were validated by irradiating FXG with the gamma radiation at 1-200 Gy. To evaluate the long- and short-term consistency and reproducibility of FXG, the optical density was measured at 24, 48 and 120 h after irradiation. Light absorbance spectra were analyzed from 350-700 nm. Spectrophotometric measurement of FXG demonstrated the linearity up to 30 Gy, and then gradually reached a plateau. FXG showed a good stability over a period of 120 h after exposure to gamma radiation. FXG showed a high reproducibility which is in comparable to that of obtained from the ionization chamber. The FXG showed high accuracy, sensitivity and reproducibility, thus enabling determination of absorbed dose from the external beam radiotherapy.

Evaluation of patient radiation dose after the implementation of a high kV technique during a cerebral angiographic procedure is an important issue. This study aimed to determine and compare the patient radiation dose of intracranial aneurysm patients undergoing cerebral angiography using the conventional and high kV techniques in a retrospective study and a phantom study. A total of 122 cases (61 cases with conventional technique and 61 cases with high kV technique) of intracranial aneurysm patients, who underwent cerebral angiographic procedure and met the inclusion criteria, were recruited. The radiation dose and the angiographic exposure parameters were reviewed retrospectively. The radiation dose in the phantom study was conducted using nanoDotTM optically stimulating luminescence (OSLD), which were placed on the scalp of the head phantom, the back of the neck, and the phantom skin at the position of the eyes. The standard cerebral angiographic procedure using the conventional and high kV techniques was performed following the standard protocol. The results showed that the high kV technique significantly reduced patient radiation dose and phantom skin dose. This study confirms that the implementation of a high kV technique in routine cerebral angiography for aneurysm diagnosis provides an effective reduction in radiation dose. Further investigation of radiation dose in other interventional neuroradiology procedures, particularly embolization procedure, should be performed.