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Radiation protection for interventional radiology (IR) physicians is very important. Current IR X-ray systems tend to use flat-panel detectors (FPDs) rather than image intensifiers (IIs). The purpose of this study is to test the hypothesis that there is no difference in physician-received scatter radiation (PRSR) between FPD systems and II systems. This study examined 20 X-ray systems in 15 cardiac catheterisation laboratories (11 used a FPD and 9 used an II). The PRSR with digital cineangiography and fluoroscopy were compared among the 20 X-ray systems using a phantom and a solid-state-detector electronic pocket dosemeter. The maximum PRSR exceeded the minimum PRSR by ∼12-fold for cineangiography and ∼9-fold for fluoroscopy. For both fluoroscopy and digital cineangiography, the PRSR had a statistically significant positive correlation with the entrance surface dose (fluoroscopy, r = 0.87; cineangiography, r = 0.86). There was no statistically significant difference between the average PRSR of FPDs and IIs during either digital cineangiography or fluoroscopy. There is a wide range of PRSR among the radiography systems evaluated. The PRSR correlated well with the entrance surface dose of the phantom in 20 X-ray units used for IR. Hence, decreasing the dose to the patient will also decrease the dose to staff. [ABSTRACT FROM PUBLISHER]

Many of the X-ray systems that are used for cardiac interventional radiology provide no way to evaluate the patient maximum skin dose (MSD). The authors report a new method for evaluating the MSD by using the cumulative patient entrance skin dose (ESD), which includes a back-scatter factor and the number of cineangiography frames during percutaneous coronary intervention (PCI). Four hundred consecutive PCI patients (315 men and 85 women) were studied. The correlation between the cumulative ESD and number of cineangiography frames was investigated. The irradiation and overlapping fields were verified using dose-mapping software. A good correlation was found between the cumulative ESD and the number of cineangiography frames. The MSD could be estimated using the proportion of cineangiography frames used for the main angle of view relative to the total number of cineangiography frames and multiplying this by the cumulative ESD. The average MSD (3.0±1.9 Gy) was lower than the average cumulative ESD (4.6±2.6 Gy). This method is an easy way to estimate the MSD during PCI. [ABSTRACT FROM PUBLISHER]

In this study, the entrance surface dose rates received by a phantom during cineangiography and fluoroscopy were compared. The X-ray conditions used in the measurements were those normally used in facilities performing percutaneous coronary intervention. Although, today, the entrance surface doses (cineangiography and fluoroscopy) of X-ray equipment used for cardiac interventional radiology (IVR) tends to be lower than they were previously, some equipment produces a high radiation dose. Therefore, the X-ray equipment used for cardiac IVR procedures must be maintained in good repair and must be carefully calibrated. In addition, periodic measurement of the radiation dose from the X-ray equipment used for both cineangiography and fluoroscopy for cardiac IVR is necessary. If the radiation dose of the X-ray system in use is too high, the IVR staff should determine the reason and make an effort to reduce it. Hence, the IVR staff must be adequately trained in radiation protection. [ABSTRACT FROM PUBLISHER]

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 ∼20% less than the lead aprons, and are non-toxic. [ABSTRACT FROM AUTHOR]

Full-spinal radiographs (FRs) are often the first choice of imaging modality in the investigation of scoliosis. However, FRs are strongly related to breast cancer occurrence due to multiple large-field radiographic examinations taken during childhood and adolescence, which may increase the risk for breast cancer in adulthood among women with scoliosis. The purpose of this study was to consider various technical parameters to reduce the patient radiation dose of FRs for scoliosis. To evaluate breast surface doses (BSDs) in FRs, radio photoluminescence dosimeters were placed in contact with a child phantom. Using the PC-based Monte Carlo (PMC) program for calculating patient doses in medical X-ray examinations, the breast organ dose (BOD) and the effective dose were calculated by performing Monte Carlo simulations using mathematical phantom models. The BSDs in the posteroanterior (PA) view were 0.15–0.34-fold those in the anteroposterior (AP) view. The effective dose in the PA view was 0.4–0.61-fold that in the AP view. BSD measurements were almost equivalent to the BODs obtained using PMC at all exposure settings. During FRs, the PA view without an anti-scatter grid significantly reduced the breast dose compared to the AP view with an anti-scatter grid. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Biodosimetry is a useful method for estimating personal exposure doses to ionizing radiation. Studies have identified metabolites in non-cellular biofluids that can be used as markers in biodosimetry. Levels of metabolites in blood cells may reflect health status or environmental stresses differentially. Here, we report changes in the levels of murine blood cell metabolites following exposure to X-rays in vivo. Levels of blood cell metabolites were measured by capillary electrophoresis time-of-flight mass spectrometry. The levels of 100 metabolites were altered substantially following exposure. We identified 2-aminobutyric acid, 2′-deoxycytidine, and choline as potentially useful markers of radiation exposure and established a potential prediction panel of the exposure dose using stepwise regression. Levels of blood cell metabolites may be useful biomarkers in estimating exposure doses during unexpected radiation incidents. [ABSTRACT FROM AUTHOR]

After the Fukushima nuclear power plant accident in 2011, many types of survey meters were used, including Geiger–Müller (GM) survey meters, which have long been used to measure β-rays. Recently, however, a novel radiation survey meter that uses a plastic-scintillation sensor has been developed. Although manufacturers' catalog data are available for these survey meters, there have been no user reports on performance. In addition, the performance of commercial plastic-scintillation survey meters has not been evaluated. In this study, we experimentally compared the performance of a plastic-scintillation survey meter with that of a GM survey meter. The results show that the two instruments performed very similarly in most respects. The GM survey meter exhibited count losses when the radiation count rate was high, whereas the plastic-scintillation survey meter remained accurate under such circumstances, with almost no count loss at high radiation rates. For measurements at background rates (i.e., low counting rates), the counting rates of the plastic-scintillation and GM survey meters were similar. Therefore, an advantage of plastic-scintillation survey meters is that they are less affected by count loss than GM survey meters. We conclude that the plastic-scintillation survey meter is a useful β-ray measuring/monitoring instrument. [ABSTRACT FROM AUTHOR]

Purpose: Since childhood exposure to radiation has been demonstrated to increase cancer risk with increase in radiation dose, reduced radiation exposure during computed tomography (CT) evaluation is desired for adolescent idiopathic scoliosis (AIS). Therefore, this retrospective study aimed to investigate the radiation dose of dual-source CT using a spectral shaping technique and the accuracy of the thoracic pedicle screw (TPS) placement for posterior spinal fusion (PSF) in patients with AIS. Methods: Fifty-nine female patients with thoracic AIS who underwent PSF using CT-guided TPSs were included and divided into two groups comprised of 23 patients who underwent dual-source CT (DSCT) with a tin filter (DSCT group) and 36 who underwent conventional multislice CT (MSCT group). We assessed the CT radiation dose using the CT dose index (CTDIvol), effective dose (ED), and accuracy of TPS insertion according to the established Neo's classification. Results: The DSCT and MSCT groups differed significantly (p < 0.001) in the mean CTDIvol (0.76 vs. 3.31 mGy, respectively) and ED (0.77 vs. 3.47 mSv, respectively). Although the correction rate of the main thoracic curve in the DSCT group was lower (65.7% vs. 71.2%) (p = 0.0126), the TPS accuracy (Grades 0–1) was similar in both groups (381 screws [88.8%] vs. 600 screws [88.4%], respectively) (p = 0.8133). No patient required replacement of malpositioned screws. Conclusion: Spectral shaping DSCT with a tube-based tin filter allowed a 75% radiation dose reduction while achieving TPS insertion accuracy similar to procedures based on conventional CT without spectral shaping. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Interventional radiology (IVR) procedures are associated with increased radiation exposure and injury risk. Furthermore, radiation eye injury (i.e., cataract) in IVR staff have also been reported. It is crucial to protect the eyes of IVR physicians from X-ray radiation exposure. Many IVR physicians use protective Pb eyeglasses to reduce occupational eye exposure. However, the shielding effects of Pb eyeglasses are inadequate. We developed a novel shield for the face (including eyes) of IVR physicians. The novel shield consists of a neck and face guard (0.25 mm Pb-equivalent rubber sheet, nonlead protective sheet). The face shield is positioned on the left side of the IVR physician. We assessed the shielding effects of the novel shield using a phantom in the IVR X-ray system; a radiophotoluminescence dosimeter was used to measure the radiation exposure. In this phantom study, the effectiveness of the novel device for protecting against radiation was greater than 80% in almost all measurement situations, including in terms of eye lens exposure. A large amount of scattered radiation reaches the left side of IVR physicians. The novel radiation shield effectively protects the left side of the physician from this scattered radiation. Thus, the device can be used to protect the face and eyes of IVR physicians from occupational radiation exposure. The novel device will be useful for protecting the face (including eyes) of IVR physicians from radiation, and thus could reduce the rate of radiation injury. Based on the positive results of this phantom study, we plan to perform a clinical experiment to further test the utility of this novel radiation shield for IVR physicians. [ABSTRACT FROM AUTHOR]

Background: A helical head CT examination uses a pitch factor (PF) of <1.0, resulting in a part of the slice being directly irradiated twice. This raises the possibility of double irradiation, which may increase the amount of radiation to the lens. Organ‐based tube current modulation (OBTCM) is an effective method for reducing lens exposure because it reduces the dose to the anterior aspect of the patient. However, it is challenging to visualize the complex dose distribution when factoring in double irradiation. Purpose: To visualize twice‐irradiated areas in helical head CT in three dimensions and to clarify the exposure reduction effect of OBTCM. Material and methods: A leuco crystal violet (LCV) dosimeter was placed into an empty polyethylene terephthalate bottle 16.5 cm in diameter. Helical scans were performed without and with OBTCM using the following parameters: tube voltage 120 kV, tube current 600 mA, pitch factor 0.637, rotation time 0.5 s, 80 (detector rows) × 0.5 mm (detector collimation), and ten scans. Exposed areas were visualized using an optical computed tomography (OCT) system designed by our group. The dose reduction rate of OBTCM was defined as the ratio of the average values of the histogram with the dose value on the x‐axis and the frequency on the y‐axis without and with OBTCM at 90° to the anterior midline. Results: The LCV dosimeter visualized the spiral‐shaped twice‐irradiated areas. Double irradiation resulted in a dose of 2.19/1.90 and 1.38/1.19 Gy (15.0% and 15.9% increase) without and with OBTCM, respectively. The dose reduction using OBTCM was 29.6% at 90° anterolateral. Conclusion: The LCV dosimeter visualized the complex three‐dimensional irradiated areas and enabled dose measurement in twice‐irradiated areas. Increased exposure from double irradiation was attenuated by OBTCM. [ABSTRACT FROM AUTHOR]

This study presents a comparison of novel pregnant model phantoms with a handmade phantom in terms of shape and radiation measurement points to determine which model is more suitable for measuring the foetal radiation dose during x-ray examinations. Novel pregnant model phantoms were constructed using an anthropomorphic phantom in combination with two differently-sized custom-made abdomen phantoms simulating pregnancy, which were constructed from a polyurethane resin. The size and shape of the polyurethane resin were designed based on abdominal sizes and shapes collected from the computed tomography examinations at 18 pregnant patients of one hospital. The handmade pregnant model phantom was constructed using an anthropomorphic phantom and a beach ball containing water. Compared with the handmade phantom, there were additional dose measurement points on the novel pregnant model phantoms. Our model phantoms improved upon the handmade phantom in terms of shape and radiation measurement points. We produced pregnant model phantoms that simulated the shapes and sizes of actual patients for the first time. [ABSTRACT FROM AUTHOR]