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In 2011, the International Commission on Radiological Protection (ICRP) recommended a significant reduction in the lens-equivalent radiation dose limit, thus from an average of 150 to 20 mSv/year over 5 years. In recent years, the occupational dose has been rising with the increased sophistication of interventional radiology (IVR); management of IVR staff radiation doses has become more important, making real-time radiation monitoring of such staff desirable. Recently, the i3 real-time occupational exposure monitoring system (based on RaySafeTM) has replaced the conventional i2 system. Here, we compared the i2 and i3 systems in terms of sensitivity (batch uniformity), tube-voltage dependency, dose linearity, dose-rate dependency, and angle dependency. The sensitivity difference (batch uniformity) was approximately 5%, and the tube-voltage dependency was <±20% between 50 and 110 kV. Dose linearity was good (R2 = 1.00); a slight dose-rate dependency (~20%) was evident at very high dose rates (250 mGy/h). The i3 dosimeter showed better performance for the lower radiation detection limit compared with the i2 system. The horizontal and vertical angle dependencies of i3 were superior to those of i2. Thus, i3 sensitivity was higher over a wider angle range compared with i2, aiding the measurement of scattered radiation. Unlike the i2 sensor, the influence of backscattered radiation (i.e., radiation from an angle of 180°) was negligible. Therefore, the i3 system may be more appropriate in areas affected by backscatter. In the future, i3 will facilitate real-time dosimetry and dose management during IVR and other applications.

The new recommendation of the International Commission on Radiological Protection for occupational eye dose is an equivalent dose limit to the eye of 20 mSv year-1, averaged over a 5-year period. This recommendation is a drastic reduction from the previous limit of 150 mSv year-1. Hence, it is important to protect physicians' eyes from X-ray radiation. Particularly in interventional radiology (IVR) procedures, many physicians use protective lead (Pb) glasses to reduce their occupational exposure. This study assessed the shielding effects of novel 0.07 mm Pb glasses. The novel glasses (XR-700) have Pb-acrylic lens molded in three dimensions. We studied the novel type of 0.07 mm Pb glasses over a period of seven consecutive months. The eye dose occupational radiation exposure of seven IVR physicians was evaluated during various procedures. All IVR physicians wore eye dosimeters (DOSIRIS™) close to the left side of the left eye. To calculate the shielding effects of the glasses, this same type of eye dosimeter was worn both inside and outside of the Pb lenses. The average shielding effect of the novel glasses across the seven physicians was 61.4%. Our results suggest an improved shielding effect for IVR physicians that use these glasses. No physician complained that the new glasses were uncomfortable; therefore comfort is not a problem. The lightweight glasses were acceptable to IVR physicians, who often must perform long procedures. Thus, the novel glasses are comfortable and reasonably protective. Based on the results of this study, we recommend that IVR physicians use these novel 0.07 mm Pb glasses to reduce their exposure., (© The Author(s) 2021. Published by Oxford University Press on behalf of The Japanese Radiation Research Society and Japanese Society for Radiation Oncology.)

Radiation exposure during interventional radiology (IR) procedures is a critical issue. We have developed a wireless real-time dosimeter for IR patients that use nontoxic phosphor (four sensors). We evaluated the basic performance parameters (such as dose linearity, batch uniformity, reproducibility, and wireless-communication conditions) of the developed system using an IR X-ray system. Further, we investigated the influence of noise from other medical equipment on our wireless real-time dosimeter in the IR X-ray room. Overall, our wireless system exhibited excellent performance in terms of uniformity, reproducibility, and linearity; moreover, the wireless communication performance was better. The developed system enabled real-time visualization of patient radiation dose, without noise contamination from other medical equipment. In addition, the wireless system can be easily installed in a location where the PC screen (display) can be readily viewed by the IR physician. Hence, we developed a wireless system that can display the patient radiation dose data in real time; the system performed satisfactorily upon application in radiation dosimetry. Therefore, our wireless system will facilitate the real-time monitoring/management of patient radiation dose during IR.

Radiation dose management is important in interventional radiology (IR) procedures, such as percutaneous coronary intervention, to prevent radiation-induced injuries. Therefore, radiation dose should be monitored in real time during IR. This study evaluated the fundamental characteristics of a novel real-time skin dosimeter (RTSD) developed at our institution. In addition, we compared the performance of our new and old radiation sensors and that of a skin dose monitor (SDM), with ion chamber reference values. We evaluated the fundamental characteristics (e.g., energy dependence, dose dependence, and angular dependence) of the RTSD developed by us in the diagnostic X-ray energy range. The performance of our RTSD was similar to that of the SDM. In particular, the new radiation sensor of our RTSD demonstrated better dose rate dependence compared to the old sensor. In addition, the new sensor had the advantage of being small in size and thus minimally affecting the X-ray images compared to the old sensor. Therefore, the developed skin dosimeter and radiation sensor may be useful in real-time measurement of patients' exposure to and multi-channel monitoring of radiation in IR procedures. The new dosimeter system can be recommended for visualization and management of the radiation dose to which the patients' skin is exposed.

There are no feasible real-time and direct skin dosimeters for interventional radiology. One would be available if there were x-ray phosphors that had no brightness change caused by x-ray irradiation, but the emission of the Y 2 O 3 :Eu, (Y, Gd, Eu)BO 3 , and YVO 4 :Eu phosphors investigated in our previous study was reduced by x-ray irradiation. We found that the brightness of those phosphors recovered, and the purpose of this study is to investigate their recovery phenomena. It is expected that more kinds of phosphors could be used in x-ray dosimeters if the brightness changes caused by x-rays are elucidated and prevented. Three kinds of phosphors-Y 2 O 3 :Eu, (Y, Gd, Eu)BO 3 , and YVO 4 :Eu-were irradiated by x-rays (2 Gy) to reduce their brightness. After the irradiation, brightness changes occurring at room temperature and at 80 °C were investigated. The irradiation reduced the brightness of all the phosphors by 5%-10%, but the brightness of each recovered immediately both at room temperature and at 80 °C. The recovery at 80 °C was faster than that at room temperature, and at both temperatures the recovered brightness remained at 95%-98% of the brightness before the x-ray irradiation. The brightness recovery phenomena of Y 2 O 3 :Eu, (Y, Gd, Eu)BO 3 , and YVO 4 :Eu phosphors occurring after brightness deterioration due to x-ray irradiation were found to be more significant at 80 °C than at room temperature. More kinds of phosphors could be used in x-ray scintillation dosimeters if the reasons for the brightness changes caused by x-rays were elucidated.

There is currently no effective real-time patient dosimeter available for use in interventional radiology (IR). We conducted a feasibility study in a clinical setting to investigate the use of the new dosimeter using photoluminescence sensors during procedures. Reference dosimeters were set at almost the same position of the prototype dosimeter sensors. We found excellent correlations between the reference measurements and those of the prototype dosimeter (r 2 =0.950). The sensor of the new dosimeter does not interfere with the IR procedure. The new dosimeter will be an effective tool for the real-time measurement of patient skin doses during IR., (Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)

Japan Network for Research and Information on Medical Exposures (J-RIME) released the primary diagnostic reference levels (DRLs 2015) to optimize/manage the radiation dose for interventional radiology (IVR) on June 7, 2015 in Japan. However, this DRLs 2015 has a wide range of selection bias for only certified IVR technologists' dates. Therefore, it is important to know the radiation dose including non-certified IVR technologists' facilities. In this study, we verified the fluoroscopy radiation dose rates for many IVR systems in the present situation. This study was conducted at 13 cardiac catheterization laboratories (18 X-ray systems) around Sendai. We measured the entrance doses at the patient entrance reference point (interventional reference point) using a 20-cm-thick acrylic plate and skin-dose monitor. Although the DRLs 2015 of IVR is 20 mGy/min, the result of a fluoroscopy radiation dose in 18 X-ray systems was median (inter quartile range: IQR), 24.4 (16.3, 35.5) mGy/min. The optimization/managing the radiation dose of IVR X-ray systems is an important issue. In addition, it is necessary to intensify the activities to raise awareness for DRLs 2015.

Objective: Although many patients benefit greatly from fluoroscopically guided intervention (IVR) procedures such as percutaneous coronary intervention (PCI), one of the major disadvantages associated with these procedures, such as cardiac IVR, is the increased patient radiation dose. This study compared the entrance surface doses of x-ray equipment for cardiac IVR at the same seven cardiac catheterization laboratories between today and the past to determine the radiation doses of current cardiac IVR x-ray systems., Methods and Results: This study was conducted in 2001, 2007, and 2014 at the same seven cardiac catheterization laboratories in and around Sendai City, Japan. The entrance surface doses with cineangiography and fluoroscopy were compared in 2001 (11 x-ray systems), 2007, and 2014 (12 x-ray systems) using a 20-cm-thick acrylic plate and skin dose monitor. The x-ray conditions used in the measurements, including the image receptor field magnification mode and the recording speed for cineangiography and fluoroscopy, were those-normally used in the facilities performing PCI. Although presently, the entrance doses of x-ray equipment used for cardiac IVR tend to be lower than previously (fluoroscopy dose in 2001, 19.3 +/- 6.3 mGy/min; in 2014, 13.2 +/- 6.5 mGy/min), some equipment has a high radiation dose. In addition, the dose differences of the x-ray systems in 2014 were greater than those in the past (fluoroscopy dose in 2001, 3.4-fold; in 2014, 10.5-fold)., Conclusions: In IVR procedures, managing the radiation dose of cardiac IVR x-ray systems is a very important issue. Periodical measurement of the radiation dose of the x-ray equipment used for both cineangiography and fluoroscopy for cardiac IVR is necessary.

Real-time monitoring of the radiation doses received by interventional radiology (IR) staff has become highly desirable. However, occupational doses are rarely measured in real time, due to the lack of a feasible method for use in IR. Recently, the i2 system by RaySafe™ has been introduced to measure occupational exposure in IR in real time. The i2 system consists of several personal dosimeters (PDs) and a base station with a display and computer interfacing. We evaluated the fundamental performance (dose linearity, dose-rate dependence, angular dependence, batch uniformity and reproducibility) of the i2 system. The dose linearity of the i2 was excellent (R(2) = 1.00) The i2 exhibited slight dose-rate dependence (~20%) at very high dose rates (250 mGy h(-1)). Little angular dependence (within 20%) was observed between 0° and ±45°, in either the vertical or horizontal direction. We also found that the PD was highly sensitive (about 200%) at angles behind it, e.g. 180°. However, this backscattered radiation is not a problem, in general, due to the placement of the i2 sensor (PD) on the lead apron. We conclude that the i2 system facilitates accurate real-time monitoring and management of occupational doses during IR.

Today, interventional radiology (IR) X-ray units are required for display of doses at an interventional reference point (IRP) for the operator (IR physician). The dose displayed at the IRP (the reference dose) of an X-ray unit has been reported to be helpful for characterizing patient exposure in real time. However, no detailed report has evaluated the accuracy of the reference doses displayed on X-ray equipment. Thus, in this study, we compared the displayed reference dose to the actual measured value in many IR X-ray systems. Although the displayed reference doses of many IR X-ray systems agreed with the measured actual values within approximately 15%, the doses of a few IR units were not close. Furthermore, some X-ray units made in Japan displayed reference doses quite different from the actual measured value, probably because the reference point of these units differs from the International Electrotechnical Commission standard. Thus, IR physicians should pay attention to the location of the IRP of the displayed reference dose in Japan. Furthermore, physicians should be aware of the accuracy of the displayed reference dose of the X-ray system that they use for IR. Thus, regular checks of the displayed reference dose of the X-ray system are important.

At present, interventional radiology (IVR) tends to involve long procedures (long radiation duration), and physicians are near to the source of scattered radiation. Hence, shielding is critical in protecting physicians from radiation. Protective aprons and additional lead-shielding devices, such as tableside lead drapes, are important means of protecting the physician from scattered radiation. The purpose of this study was to evaluate whether non-lead aprons are effective in protecting physicians from radiation during IVR procedures. In this study, the radiation protection effects of commercially available protective lead and non-lead aprons, when exposed to diagnostic X rays, are compared. The performance of these non-lead and lead aprons was similar for scattered X rays at tube voltages of 60-120 kV. Properly designed non-lead aprons are thus more suitable for physicians because they weigh approximately 20% less than the lead aprons, and are non-toxic.