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High-resolution film dosimetry has been used for several decades to check and to measure two-dimensional dose distributions. However, in recent years, the automatic processor has been replaced by the spread of computed radiography, or has been little used hospitals. In this study, we measured the off-center ratio (OCR) of the open field, after an irradiating radiation beam was delivered to the imaging plate (IP) under conditions in which the IP was exposed to a fixed amount of light with fading, and compared these data with the OCR measured by an ionization-chamber dosimeter, which is the standard method used for measuring radiation dose. Profile measurement using IP could be achieved by performing light fading, even at a range of more than 100 MU. Further, by using a metallic filter, we succeeded in demonstrating that the profile measurement of IP in an open irradiation field could approximate the values of those obtained by an ionization chamber dosimeter. This method can serve as a simple, easy-to-use method for evaluating the QA of dose distribution in radiation therapy.

It is important to grasp how much radiation exposure has occurred through radiation diagnosis, in respect to patient explanations and radiation protection. In this examination, we used a patient skin dosimeter (PSD) that measures entrance surface dose (ESD) in real time using a fluoroscopy procedure. The PSD has the ability to display results beginning at 1 microGy. We focused our attention on the X-ray detectability of the PSD, and performed a representative evaluation with the X-ray equipment. We measured ESD under various radiographic parameters at our facility. Although the measurements were dependent on energy, we were able to measure ESD to within an accuracy of about a 5% error by putting a calibration value on energy. The PSD can measure ESD easily without requiring preparation. It is important to be aware of the exposure dose to the radiation staff, and the PSD is a very effective radiation dose-measuring tool when daily business is active.

Purpose: In this study, we created a whole body fusion image of PET and MRI using automated software for fusion imaging, and assessed the accuracy of the software., Materials and Methods: Twenty patients with abnormal FDG-PET findings underwent whole body MRI. Images from both modalities were automatically fused in two ways using software (Fusion Viewer, Nihon Medi-Physics Co., Ltd., Nishinomiya, Japan) with a registration algorithm based on maximum mutual information. One was to create a whole body fusion image at once, named whole body fusion (WBF). The other was to create fusion images of the head and body separately, named partial body fusion (PBF). Two radiologists measured the misregistration between PET and MRI in the fusion images at nine landmarks (brain, cervical spine, chest, heart, liver, right kidney, left kidney, vertebra, base of bladder)., Results: When fusion images were created using WBF at once, misregistration was observed in the head and neck area in approximately half of the cases, whereas almost no misregistration was observed in the body. When fusion images were created using PBF, the misregistration in the head and neck areas was significantly smaller than in those using WBF, and misregistration in the body was very small., Conclusion: The PBF technique that creates highly accurate whole body PET/MRI fusion images is easy to use and may provide clinically useful information.