[Nationwide Questionnaire Survey on Disaster Power Outage Countermeasures in the Radiology Departments of Hospitals].

PURPOSE: To identify the countermeasures and current status of disaster power outages in the radiology departments of hospitals. METHODS: A web-based questionnaire survey of 600 hospitals nationwide was conducted. The questionnaire survey covered 34 items, including availability of power in the radiology department in the event of a disaster and the impact of power outages on medical equipment in the radiology department. RESULTS: In all, 242 facilities (40.3%) responded to our survey. During power outages, 55.8%-68.2% of facilities were able to use CT, digital radiography, and angiography systems with their private generators. In 28.1%-40.7% of facilities, medical information systems were not available in all laboratories. In addition, power outages caused equipment malfunctions in 81.4% of facilities' radiology departments. CONCLUSION: We have identified the power supplied by private generators to the radiology department's medical equipment and medical information systems. Many medical equipment have malfunctioned due to power outages. Therefore, drills should be conducted to simulate various situations caused by power outages.

LENS EQUIVALENT DOSE OF STAFF DURING ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY: DOSE COMPARISON USING TWO TYPES OF DOSEMETERS.

This study aimed to compare the lens equivalent dose (LED) measured during endoscopic retrograde cholangiopancreatography (ERCP) using DOSIRIS™ as a dedicated dosemeter to that measured using glass badges to determine if glass badges can be alternative tools for LED measurement. LEDs for physicians during ERCP were measured using the DOSIRIS™ [3-mm dose equivalent] worn on the outer edge of the eyes and personal dosemeters (glass badges) [0.07-mm dose equivalent] worn on the right and left sides of the neck. The cumulated doses over 6 months for the left eye using DOSIRIS™ were 9.5 and 11.8 mSv for physicians A and B, whereas doses measured using glass badges were 7.5 and 11.6 mSv, respectively. The LEDs of the physicians at the left eye and left neck side showed almost similar values and were significantly correlated (r = 0.95; p < 0.01). For an accurate LED measurement during ERCP, using a dosemeter such as DOSIRIS™ is recommended, although similar LED estimation values were reported using glass badges on the left neck side.

New Radioprotective Device that can be Used for Fluoroscopic Exam: Possibility to Contribute to Staff Exposure Protection During VFSS.

The videofluoroscopic swallowing study (VFSS) is a recognized standard diagnostic imaging technique that is used to investigate swallowing disorders and dysphagia. Patients were assessed in a seated posture on a chair or wheelchair. Using X-ray fluoroscopy, the state of patients' swallowing was checked by eating and drinking according to the physician's instructions. VFSS procedures are prolonged, and VFSS staff members are exposed to radiation. Therefore, we evaluated original lead shielding device (OLSD) that can be attached to the handrail of a table and placed vertically. The OLSD has a lead-equivalent thickness of 0.3 mmPb, weighs about 6 kg, and has the dimensions 50 cm × 50 cm × 8.0 mm. We used a human phantom and a radiation survey meter with and without protection from scattered radiation at the positions of the physician and medical staff at the height of 150 cm above the floor (i.e., the height of the eye's crystalline lens). After measuring the scattered radiation, we created radiation maps with and without the OLSD. The dose rate at the physician's position without and with the OLSD was 190 µSv/h and 92 µSv/h, respectively, and a dose reduction of 51.6% with the plate. Moreover, the radiation maps added clarity to the distribution of the scattered radiation. Such information should lead to greater awareness about exposures to physicians and other medical staff. Thus, the OLSD effectively provided protection from scattered radiation at the physician's position during fluoroscopy. It may contribute to the reduction of staff exposure for VFSS.

The effectiveness of additional lead-shielding drape and low pulse rate fluoroscopy in protecting staff from scatter radiation during cardiac resynchronization therapy (CRT).

PURPOSE: Cardiac resynchronization therapy (CRT) often requires a long fluoroscopic time and protection from scatter radiation. This study reports on scatter radiation levels during CRT, with and without additional shielding, and using standard or low pulse rate fluoroscopy. MATERIALS AND METHODS: Additional lead-shielding drape (0.35-mm lead equivalent) was used on the left side of the table and pulsed fluoroscopy was performed at rates of 10 pulses/s (usual rate) and 7.5 pulses/s (low pulse rate). Fluoroscopy scatter radiation was measured for both pulse rates using an acrylic phantom with a radiation survey meter, both with and without the additional lead-shielding drape. RESULTS: With the additional lead-shielding drape, the fluoroscopy scatter radiation was reduced by 74.3% at 10 pulses/s and 78.6% at 7.5 pulses/s. If the fluoroscopy was changed from 10 pulses/s to 7.5 pulses/s, the scattered radiation at the primary physician's position was reduced by 24.0%. The combined use of additional shielding drape and low pulse rate fluoroscopy reduced scatter radiation by over 80%. CONCLUSION: Additional lead-shielding drape and low pulse rate fluoroscopy are effective in reducing the scattered radiation dose to physicians and nurses during CRT.

Effectiveness of additional lead shielding to protect staff from scattering radiation during endoscopic retrograde cholangiopancreatography procedures.

Endoscopic retrograde cholangiopancreatography (ERCP) is often complex and involves long fluoroscopic times, with significant radiation exposure to medical staff. We investigated protective effects of an additional attached lead shielding device. The lead shielding device covered with the X-ray tube table (0.125 mm lead equivalent) during ERCP procedures. Fluoroscopy scatter radiation, with or without the lead shielding device, was measured using an acrylic phantom and a radiation survey meter. Measurements (25 points) were made at 50 cm intervals, at both 90 and 150 cm above the floor. We created radiation maps, with and without the additional lead shielding device. Moreover, we monitored annual staff exposure to radiation, before and after inclusion of the shielding device. Without additional shielding, exposure doses at the physician's position, 90 and 150 cm above the floor, were 1940 and 4040 (µSv/h) respectively. In contrast, with the shielding device, corresponding exposures were 270 and 450 (µSv/h) at 90 and 150 cm, respectively. Scattered radiation was decreased by 86.1% at 90 cm or 88.9% at 150 cm. However, with additional lead shielding in the middle, rather than hung over the operating table, scattered radiation was decreased by only ~10%. The staff's annual dose equivalents (DEs) were 12.2-29.8 mSv/year without and 3.8-8.4 mSv/year with lead shielding. With lead shielding, dose equivalent values for the staff were decreased by 41.0-76.5%. Thus, with additional lead shielding, properly used, scattered radiation would be decreased by ~90%, thus decreasing exposure doses to medical staff during ERCPs.

Effectiveness of a New Lead-Shielding Device and Additional Filter for Reducing Staff and Patient Radiation Exposure During Videofluoroscopic Swallowing Study Using a Human Phantom.

Interventional radiology procedures often involve lengthy exposure to fluoroscopy-derived radiation. We therefore devised a videofluoroscopic swallowing study (VFSS) procedure using a human phantom that proved to protect the patient and physician by reducing the radiation dose. We evaluated a new lead-shielding device and separately attached additional filters (1.0-, 2.0-, and 3.0-mm Al filters and a 0.5-mm Cu filter) during VFSS to reduce the patient's entrance skin dose (ESD). A monitor attached to the human phantom's neck measured the ESD. We also developed another lead shield (VFSS Shielding Box, 1.0-mm Pb equivalent) and tested its efficacy using the human phantom and an ionization chamber radiation survey meter with and without protection from scattered radiation at the physician's position on the phantom. We then measured the scattered radiation (at 90 and 150 cm above the floor) after combining the filters with the VFSS Shielding Box. With the additional filters, the ESD was reduced by 15.4-55.1%. With the VFSS Shielding Box alone, the scattered radiation was reduced by about 10% compared with the dose without additional shielding. With the VFSS Shielding Box and filters combined, the scattered radiation dose was reduced by a maximum of about 44% at the physician's position. Thus, the additional lead-shielding device effectively provided protection from scattered radiation during fluoroscopy. These results indicate that the combined VFSS Shielding Box and filters can effectively reduce the physician's and patient's radiation doses.

Estimation of the Dose of Radiation Received by Patient and Physician During a Videofluoroscopic Swallowing Study.

Videofluoroscopic swallowing study (VFSS) is considered the standard diagnostic imaging technique to investigate swallowing disorders and dysphagia. Few studies have been reported concerning the dose of radiation a patient receives and the scattering radiation dose received by a physician during VFSS. In this study, we investigated the dose of radiation (entrance skin dose, ESD) estimated to be received by a patient during VFSS using a human phantom (via a skin-dose monitor sensor placed on the neck of the human phantom). We also investigated the effective dose (ED) and dose equivalent (DE) received by a physician (wearing two personal dosimeters) during an actual patient procedure. One dosimeter (whole body) was worn under a lead apron at the chest, and the other (specially placed to measure doses received by the lens of the eye) outside the lead apron on the neck collar to monitor radiation doses in parts of the body not protected by the lead apron. The ESD for the patient was 7.8 mGy in 5 min. We estimated the average patient dose at 12.79 mGy per VFSS procedure. The physician ED and DE during VFSS were 0.9 mSv/year and 2.3 mSv/year, respectively. The dose of radiation received by the physician in this study was lower than regulatory dose limits. However, in accordance with the principle that radiation exposure should be as low as reasonably achievable, every effort should be made (e.g., wearing lead glasses) to reduce exposure doses.

Need for radiation safety education for interventional cardiology staff, especially nurses.

OBJECTIVE: Cardiac interventional radiology (IR) can cause radiation injury to the staff who administer it as well as to patients. Although education in the basic principles of radiation is required for nurses, their level of radiation safety knowledge is not known. The present study used a questionnaire protocol to assess the level of radiation safety knowledge among hospital nurses. METHODS AND RESULTS: A questionnaire to assess the level of training and current understanding of radiation safety was administered to 305 nurses in 2008 and again to 359 nurses in 2010. Our study indicates that nurses had insufficient knowledge about radiation safety, and that a high percentage of nurses were concerned about the health hazards of radiation. Moreover, more than 80% of the nurses expressed an interest in attending periodic radiation safety seminars. Annual radiation protection training for hospital staff (including nurses) is important. CONCLUSIONS: Our results suggest that nurses do not have sufficient knowledge of radiation safety and should receive appropriate radiation safety training. Many had a minimal understanding of radiation and thus had significant concerns about the safety of working with radiation. Periodic radiation safety education/training for nurses is essential.

[Importance of radiation education for nurses].

Radiation safety education/training is essential and is associated with a reduction in the radiation dose to both patients and staff. We used a questionnaire to assess the level of radiation safety knowledge among nurses working at Tohoku Kosei-Nenkin Hospital. Some nurses were also interviewed. The results of our study indicate that the nurses had insufficient radiation safety knowledge and that a high percentage of nurses were concerned about the health hazards of radiation. Moreover, more than 80% of the nurses expressed an interest in attending periodic radiation safety seminars. Appropriate radiation safety training is required to reduce nurse radiation doses, and an understanding of radiation safety can help to optimize the patient dose.

Physician-received scatter radiation with angiography systems used for interventional radiology: comparison among many X-ray systems.

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.

Comparison of dose at an interventional reference point between the displayed estimated value and measured value.

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.

Evaluation of additional lead shielding in protecting the physician from radiation during cardiac interventional procedures.

Since cardiac interventional procedures deliver high doses of radiation to the physician, radiation protection for the physician in cardiac catheterization laboratories is very important. One of the most important means of protecting the physician from scatter radiation is to use additional lead shielding devices, such as tableside lead drapes and ceiling-mounted lead acrylic protection. During cardiac interventional procedures (cardiac IVR), however, it is not clear how much lead shielding reduces the physician dose. This study compared the physician dose [effective dose equivalent (EDE) and dose equivalent (DE)] with and without additional shielding during cardiac IVR. Fluoroscopy scatter radiation was measured using a human phantom, with an ionization chamber survey meter, with and without additional shielding. With the additional shielding, fluoroscopy scatter radiation measured with the human phantom was reduced by up to 98%, as compared with that without. The mean EDE (whole body, mean+/-SD) dose to the operator, determined using a Luxel badge, was 2.55+/-1.65 and 4.65+/-1.21 mSv/year with and without the additional shielding, respectively (p=0.086). Similarly, the mean DE (lens of the eye) to the operator was 15.0+/-9.3 and 25.73+/-5.28 mSv/year, respectively (p=0.092). In conclusion, although tableside drapes and lead acrylic shields suspended from the ceiling provided extra protection to the physician during cardiac IVR, the reduction in the estimated physician dose (EDE and DE) during cardiac catheterization with additional shielding was lower than we expected. Therefore, there is a need to develop more ergonomically useful protection devices for cardiac IVR.