Comparison of radiation-shielding curtains for endoscopic retrograde cholangiopancreatography staff.

Occupational radiation exposure to the eye lens of medical staff during endoscopic retrograde cholangiopancreatography (ERCP) should be kept low so as not to exceed annual dose limits. Dose should be low to avoid tissue reactions and minimizing stochastic effects. It is known that the head and neck of the staff are exposed to more scattered radiation in an over-couch tube system than in a C-arm system (under-couch tube). However, this is only true when radiation-shielding curtains are not used. This study aimed to compare the protection radiation to the occupationally exposed worker between a lead curtain mounted on a C-arm system and an ERCP-specific lead curtain mounted on an over-couch tube system. A phantom study simulating a typical setting for ERCP procedures was conducted, and the scattered radiation dose at four staff positions were measured. It was found that scattered radiation doses were higher in the C-arm with a lead curtain than in the over-couch tube with an ERCP-specific lead curtain at all positions measured in this study. It was concluded that the over-couch tube system with an ERCP-specific lead curtain would reduce the staff eye dose by less than one-third compared to the C-arm system with a lead curtain. For the C-arm system, it is necessary to consider more effective radiation protection measures for the upper body of the staff, such as a ceiling-suspended lead screen or another novel shielding that do not interfere with procedures.

Comparison of shielding effects of over-glasses-type and regular eyewear in terms of occupational eye dose reduction.

Given the new recommendations for occupational eye lens doses, various lead glasses have been used to reduce irradiation of interventional radiologists. However, the protection afforded by lead glasses over prescription glasses (thus over-glasses-type eyewear) has not been considered in detail. We used a phantom to compare the protective effects of such eyewear and regular eyewear of 0.07 mm lead-equivalent thickness. The shielding rates behind the eyewear and on the surface of the left eye of an anthropomorphic phantom were calculated. The left eye of the phantom was irradiated at various angles and the shielding effects were evaluated. We measured the radiation dose to the left side of the phantom using RPLDs attached to the left eye and to the surface/back of the left eyewear. Over-glasses-type eyewear afforded good protection against x-rays from the left and below; the average shielding rates on the surface of the left eye ranged from 0.70-0.72. In clinical settings, scattered radiation is incident on physicians' eyes from the left and below, and through any gap in lead glasses. Over-glasses-type eyewear afforded better protection than regular eyewear of the same lead-equivalent thickness at the irradiation angles of concern in clinical settings. Although clinical evaluation is needed, we suggest over-glasses-type Pb eyewear even for physicians who do not wear prescription glasses.

Evaluation of a New Real-Time Dosimeter Sensor for Interventional Radiology Staff.

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.

Fundamental study on diagnostic reference level quantities for endoscopic retrograde cholangiopancreatography using a C-arm fluoroscopy system.

The diagnostic reference level (DRL) is an effective tool for optimising protection in medical exposures to patients. However regarding air kerma at the patient entrance reference point (Ka,r), one of the DRL quantities for endoscopic retrograde cholangiopancreatography (ERCP), manufacturers use a variety of the International Electrotechnical Commission and their own specific definitions of the reference point. The research question for this study was whetherKa,ris appropriate as a DRL quantity for ERCP. The purpose of this study was to evaluate the difference betweenKa,rand air kerma incident on the patient's skin surface (Ka,e) at the different height of the patient couch for a C-arm system. Fluoroscopy and radiography were performed using a C-arm system (Ultimax-i, Canon Medical Systems, Japan) and a over-couch tube system (CUREVISTA Open, Fujifilm Healthcare, Japan).Ka,ewas measured by an ion chamber placed on the entrance surface of the phantom. Kerma-area product (PKA) andKa,rwere measured by a built-inPKAmeter and displayed on the fluoroscopy system.Ka,edecreased whileKa,rincreased as the patient couch moved away from the focal spot. The uncertainty of theKa,e/Ka,rratio due to the different height of the patient couch was estimated to be 75%-94%.Ka,rmay not accurately representKa,e.PKAwas a robust DRL quantity that was independent of the patient couch height. We cautioned against optimising patient doses in ERCP with DRLs set in terms ofKa,rwithout considering the patient couch height of the C-arm system. Therefore, we recommend thatKa,ris an inappropriate DRL quantity in ERCP using the C-arm system.

Evaluation of radiation dose and image quality for dental cone-beam computed tomography in pediatric patients.

Children are sensitive to radiation; therefore, it is necessary to reduce radiation dose as much as possible in pediatric patients. In addition, it is crucial to investigate the optimal imaging conditions as they considerably affect the radiation dose. In this study, we investigated the effect of different imaging conditions on image quality and optimized the imaging conditions for dental cone-beam computed tomography (CBCT) examinations to diagnose ectopic eruptions and impacted teeth in children. To achieve our aims, we evaluated radiation doses and subjective and objective image quality. The CBCT scans were performed using 3D Accuitomo F17. All combinations of a tube voltage (90 kV), tube currents (1, 2, 3 mA), fields of view (FOVs) (4 × 4, 6 × 6 cm), and rotation angles (360°, 180°) were used. Dose-area product values were measured. SedentexCT IQ cylindrical phantom was used to physically evaluate the image quality. We used the modulation transfer function as an index of resolution, the noise power spectrum as an index of noise characteristics, and the system performance function as an overall evaluation index of the image. Five dentists visually evaluated the images from the head-neck phantom. The results showed that the image quality tended to worsen, and scores for visual evaluation decreased as tube currents, FOVs and rotation angles decreased. In particular, image noise negatively affected the delineation of the periodontal ligament space. The optimal imaging conditions were 90 kV, 2 mA, 4 × 4 cm FOV and 180° rotation. These results suggest that CBCT radiation doses can be significantly reduced by optimizing the imaging conditions.

Development of Novel Real-Time Radiation Systems Using 4-Channel Sensors.

Radiation-related tissue injuries after medical radiation procedures, such as fluoroscopically guided intervention (FGI), have been reported in patients. Real-time monitoring of medical radiation exposure administered to patients during FGI is important to avoid such tissue injuries. In our previous study, we reported a novel (prototype) real-time radiation system for FGI. However, the prototype sensor indicated low sensitivity to radiation exposure from the side and back, although it had high-quality fundamental characteristics. Therefore, we developed a novel 4-channel sensor with modified shape and size than the previous sensor, and evaluated the basic performance (i.e., measured the energy, dose linearity, dose rate, and angular dependence) of the novel and previous sensors. Both sensors of our real-time dosimeter system demonstrated the low energy dependence, excellent dose linearity (R2 = 1.0000), and good dose rate dependence (i.e., within 5% statistical difference). Besides, the sensitivity of 0° ± 180° in the horizontal and vertical directions was almost 100% sensitivity for the new sensor, which significantly improved the angular dependence. Moreover, the novel dosimeter exerted less influence on X-ray images (fluoroscopy) than other sensors because of modifying a small shape and size. Therefore, the developed dosimeter system is expected to be useful for measuring the exposure of patients to radiation doses during FGI procedures.

Red-emission phosphor's brightness deterioration by x-ray and brightness recovery phenomenon by heating.

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 Y2O3:Eu, (Y, Gd, Eu)BO3, and YVO4: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-Y2O3:Eu, (Y, Gd, Eu)BO3, and YVO4: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 Y2O3:Eu, (Y, Gd, Eu)BO3, and YVO4: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.

A cross-sectional study of the radiation dose and image quality of X-ray equipment used in IVR.

There are case reports of injuries caused by the radiation from interventional radiology (IVR) X-ray systems. Therefore, the management of radiation doses in IVR is important. However, no detailed report has evaluated image quality for a large number of IVR X-ray systems. As a result, it is unclear whether the image quality of the X-ray equipment currently used in IVR procedures is optimal. We compared the entrance surface doses and image quality of multiple IVR X-ray systems. This study was conducted in 2014 at 13 medical facilities using 18 IVR X-ray systems. We evaluated image quality and simultaneously measured the radiation dose. Entrance surface doses for fluoroscopy (duration, 1 min) and cineradiography (duration, 10 s) are measured using a 20-cm-thick acrylic plate and skin dose monitor. The image quality (such as spatial resolution and low-contrast detectability) of both fluoroscopy and cineradiography was evaluated using a QC phantom. For fluoroscopy, the average entrance surface dose using the 20-cm-thick acrylic plate was 13.9 (range 2.1-28.2) mGy/min. For cineradiography, the average entrance surface dose was 24.6 (range 5.1-49.3) mGy/10 s. We found positive correlations between radiation doses and image quality scores, in general, especially for fluoroscopy. The differences in surface dose among the 18 IVR X-ray systems were high (max/min, 9.7-fold for cineradiography; 13.4-fold for fluoroscopy). The differences in image quality scores (spatial resolution, low-contrast detectability, and dynamic range) were also very large. In general, there tended to be a correlation between radiation dose and image quality. Periodical measurements of the radiation dose and image quality of the X-ray equipment used for cineradiography and fluoroscopy in IVR are necessary. The need to minimize patient exposure requires that the dose be reduced to the minimum level that will generate an image with an acceptable degree of noise.

A Rotatable Quality Control Phantom for Evaluating the Performance of Flat Panel Detectors in Imaging Moving Objects.

As the use of diagnostic X-ray equipment with flat panel detectors (FPDs) has increased, so has the importance of proper management of FPD systems. To ensure quality control (QC) of FPD system, an easy method for evaluating FPD imaging performance for both stationary and moving objects is required. Until now, simple rotatable QC phantoms have not been available for the easy evaluation of the performance (spatial resolution and dynamic range) of FPD in imaging moving objects. We developed a QC phantom for this purpose. It consists of three thicknesses of copper and a rotatable test pattern of piano wires of various diameters. Initial tests confirmed its stable performance. Our moving phantom is very useful for QC of FPD images of moving objects because it enables visual evaluation of image performance (spatial resolution and dynamic range) easily.

Novel Dosimeter Using a Nontoxic Phosphor for Real-Time Monitoring of Patient Radiation Dose in Interventional Radiology.

OBJECTIVE: To our knowledge, no feasible method exists for real-time measurement of the radiation dose given to the patient during interventional radiology (IR) procedures. Therefore, we produced a prototype of a real-time dosimeter for patients undergoing IR that uses a nontoxic phosphor. The basic characteristics of the real-time dosimeter prototype are comparable to those of the previously used skin dose monitor, with the exception that our prototype has the distinct advantage of including multichannel sensors. CONCLUSION: The novel real-time dosimeter system is expected to be useful for measuring patient exposure to the radiation dose during IR procedures.

Radiation dose of cardiac IVR x-ray systems: a comparison of present and past.

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.

Fundamental study of a real-time occupational dosimetry system for interventional radiology staff.

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.

Effect of backscatter radiation on the occupational eye-lens dose.

We quantified the level of backscatter radiation generated from physicians' heads using a phantom. We also evaluated the shielding rate of the protective eyewear and optimal placement of the eye-dedicated dosimeter (skin surface or behind the Pb-eyewear). We performed diagnostic X-rays of two head phantoms: Styrofoam (negligible backscatter radiation) and anthropomorphic (included backscatter radiation). Radiophotoluminescence glass dosimeters were used to measure the eye-lens dose, with or without 0.07-mm Pb-equivalent protective eyewear. We used tube voltages of 50, 65 and 80 kV because the scattered radiation has a lower mean energy than the primary X-ray beam. The backscatter radiation accounted for 17.3-22.3% of the eye-lens dose, with the percentage increasing with increasing tube voltage. Furthermore, the shielding rate of the protective eyewear was overestimated, and the eye-lens dose was underestimated when the eye-dedicated dosimeter was placed behind the protective eyewear. We quantified the backscatter radiation generated from physicians' heads. To account for the effect of backscatter radiation, an anthropomorphic, rather than Styrofoam, phantom should be used. Close contact of the dosimeter with the skin surface is essential for accurate evaluation of backscatter radiation from physician's own heads. To assess the eye-lens dose accurately, the dosimeter should be placed near the eye. If the dosimeter is placed behind the lens of the protective eyewear, we recommend using a backscatter radiation calibration factor of 1.2-1.3.

Occupational dose in interventional radiology procedures.

OBJECTIVE: Interventional radiology tends to involve long procedures (i.e., long fluoroscopic times). Therefore, radiation protection for interventional radiology staff is an important issue. This study describes the occupational radiation dose for interventional radiology staff, especially nurses, to clarify the present annual dose level for interventional radiology nurses. MATERIALS AND METHODS: We compared the annual occupational dose (effective dose and dose equivalent) among interventional radiology staff in a hospital where 6606 catheterization procedures are performed annually. The annual occupational doses of 18 physicians, seven nurses, and eight radiologic technologists were recorded using two monitoring badges, one worn over and one under their lead aprons. RESULTS: The annual mean ± SD effective dose (range) to the physicians, nurses, and radiologic technologists using two badges was 3.00 ± 1.50 (0.84-6.17), 1.34 ± 0.55 (0.70-2.20), and 0.60 ± 0.48 (0.02-1.43) mSv/y, respectively. Similarly, the annual mean ± SD dose equivalent range was 19.84 ± 12.45 (7.0-48.5), 4.73 ± 0.72 (3.9-6.2), and 1.30 ± 1.00 (0.2-2.7) mSv/y, respectively. The mean ± SD effective dose for the physicians was 1.02 ± 0.74 and 3.00 ± 1.50 mSv/y for the one- and two-badge methods, respectively (p < 0.001). Similarly, the mean ± SD effective dose for the nurses (p = 0.186) and radiologic technologists (p = 0.726) tended to be lower using the one-badge method. CONCLUSION: The annual occupational dose for interventional radiology staff was in the order physicians > nurses > radiologic technologists. The occupational dose determined using one badge under the apron was far lower than the dose obtained with two badges in both physicians and nonphysicians. To evaluate the occupational dose correctly, we recommend use of two monitoring badges to evaluate interventional radiology nurses as well as physicians.

Eye Lens Radiation Dose to Nurses during Cardiac Interventional Radiology: An Initial Study.

Although interventional radiology (IVR) is preferred over surgical procedures because it is less invasive, it results in increased radiation exposure due to long fluoroscopy times and the need for frequent imaging. Nurses engaged in cardiac IVR receive the highest lens radiation doses among medical workers, after physicians. Hence, it is important to measure the lens exposure of IVR nurses accurately. Very few studies have evaluated IVR nurse lens doses using direct dosimeters. This study was conducted using direct eye dosimeters to determine the occupational eye dose of nurses engaged in cardiac IVR, and to identify simple and accurate methods to evaluate the lens dose received by nurses. Over 6 months, in a catheterization laboratory, we measured the occupational dose to the eyes (3 mm dose equivalent) and neck (0.07 mm dose equivalent) of nurses on the right and left sides. We investigated the relationship between lens and neck doses, and found a significant correlation. Hence, it may be possible to estimate the lens dose from the neck badge dose. We also evaluated the appropriate position (left or right) of eye dosimeters for IVR nurses. Although there was little difference between the mean doses to the right and left eyes, that to the right eye was slightly higher. In addition, we investigated whether it is possible to estimate doses received by IVR nurses from patient dose parameters. There were significant correlations between the measured doses to the neck and lens, and the patient dose parameters (fluoroscopy time and air kerma), implying that these parameters could be used to estimate the lens dose. However, it may be difficult to determine the lens dose of IVR nurses accurately from neck badges or patient dose parameters because of variation in the behaviors of nurses and the procedure type. Therefore, neck doses and patient dose parameters do not correlate well with the radiation eye doses of individual IVR nurses measured by personal eye dosimeters. For IVR nurses with higher eye doses, more accurate measurement of the radiation doses is required. We recommend that a lens dosimeter be worn near the eyes to measure the lens dose to IVR nurses accurately, especially those exposed to relatively high doses.

Spatial Scattering Radiation to the Radiological Technologist during Medical Mobile Radiography.

Mobile radiography allows for the diagnostic imaging of patients who cannot move to the X-ray examination room. Therefore, mobile X-ray equipment is useful for patients who have difficulty with movement. However, staff are exposed to scattered radiation from the patient, and they can receive potentially harmful radiation doses during radiography. We estimated occupational exposure during mobile radiography using phantom measurements. Scattered radiation distribution during mobile radiography was investigated using a radiation survey meter. The efficacy of radiation-reducing methods for mobile radiography was also evaluated. The dose decreased as the distance from the X-ray center increased. When the distance was more than 150 cm, the dose decreased to less than 1 µSv. It is extremely important for radiological technologists (RTs) to maintain a sufficient distance from the patient to reduce radiation exposure. The spatial dose at eye-lens height increases when the bed height is high, and when the RT is short in stature and abdominal imaging is performed. Maintaining sufficient distance from the patient is also particularly effective in limiting radiation exposure of the eye lens. Our results suggest that the doses of radiation received by staff during mobile radiography are not significant when appropriate radiation protection is used. To reduce exposure, it is important to maintain a sufficient distance from the patient. Therefore, RTs should bear this is mind during mobile radiography.

Occupational eye dose correlation with neck dose and patient-related quantities in interventional cardiology procedures.

Occupational eye dose monitoring during interventional radiology and interventional cardiology is important to avoid radiation-induced cataracts. The aim of this study was to assess the eye dose correlation with neck dose and patient-related quantities for interventional cardiology physicians and nurses. The originality of this study lies in obtaining correlations between the location of the dosimeter and eye dose radiation readings among different procedures and practitioners. The doses were measured for each procedure (18 procedures of coronary angiography and 16 procedures of percutaneous coronary intervention) using an active personal dosimeter. The eye dose for physicians was not correlated with the neck dose. The eye dose for nurses had a good correlation with the neck dose during both coronary angiography (R2 = 0.91) and percutaneous coronary intervention (R2 = 0.93). Kerma-area product values may be used for a rough estimation of the eye dose for physicians during routine coronary angiography procedures (R2 = 0.76). For nurses, the neck dose is a good proxy for the eye dose during coronary angiography and percutaneous coronary intervention procedures.

Clarifying and visualizing sources of staff-received scattered radiation in interventional procedures.

OBJECTIVE: Interventional radiology tends to involve long procedures (i.e., long fluoroscopic times). Therefore, radiation protection for interventional radiology physicians and staff is an important issue. We examine and identify sources of staff-received scattered radiation in an interventional radiology system using a pinhole camera method. CONCLUSION: Physicians and staff are exposed primarily to two sources of scattered radiation: radiation scattered from the patient and radiation from the cover of the x-ray beam collimating device. Those who stand close to the patient and the x-ray beam collimating device, where scattered radiation is higher, have higher radiation doses. Thus, radiation protection during interventional radiology procedures is an important problem.

Non-Lead Protective Aprons for the Protection of Interventional Radiology Physicians from Radiation Exposure in Clinical Settings: An Initial Study.

Radiation protection/evaluation during interventional radiology (IVR) poses a very important problem. Although IVR physicians should wear protective aprons, the IVR physician may not tolerate wearing one for long procedures because protective aprons are generally heavy. In fact, orthopedic problems are increasingly reported in IVR physicians due to the strain of wearing heavy protective aprons during IVR. In recent years, non-Pb protective aprons (lighter weight, composite materials) have been developed. Although non-Pb protective aprons are more expensive than Pb protective aprons, the former aprons weigh less. However, whether the protective performance of non-Pb aprons is sufficient in the IVR clinical setting is unclear. This study compared the ability of non-Pb and Pb protective aprons (0.25- and 0.35-mm Pb-equivalents) to protect physicians from scatter radiation in a clinical setting (IVR, cardiac catheterizations, including percutaneous coronary intervention) using an electric personal dosimeter (EPD). For radiation measurements, physicians wore EPDs: One inside a personal protective apron at the chest, and one outside a personal protective apron at the chest. Physician comfort levels in each apron during procedures were also evaluated. As a result, performance (both the shielding effect (98.5%) and comfort (good)) of the non-Pb 0.35-mm-Pb-equivalent protective apron was good in the clinical setting. The radiation-shielding effects of the non-Pb 0.35-mm and Pb 0.35-mm-Pb-equivalent protective aprons were very similar. Therefore, non-Pb 0.35-mm Pb-equivalent protective aprons may be more suitable for providing radiation protection for IVR physicians because the shielding effect and comfort are both good in the clinical IVR setting. As non-Pb protective aprons are nontoxic and weigh less than Pb protective aprons, non-Pb protective aprons will be the preferred type for radiation protection of IVR staff, especially physicians.