A method using europium-doped BaFBr imaging plates (IPs) has been studied for mapping entrance skin doses during interventional radiology (IR); the mapping is useful for detecting overlap between irradiation fields and determining the most exposed skin areas. IPs, which are two-dimensional radiation sensors made of photostimulated luminescence materials, have a linear dose response up to approximately 100 Gy, can accurately measure doses from 1 microGy to 10 Gy and can be used repeatedly. Because the energy dependence of IPs is rather high, the IPs were characterised in this study and a sensitivity variation of approximately 13% was observed for effective energies of 32.7 to 44.7 keV, which are used in IR procedures. Simulation of actual interventional cardiology procedures showed that the variation of sensitivity was within 5%, meaning that IPs are practical for measuring skin doses during IR. Moreover, the patient data can be stored online and easily called up when IR procedures must be repeated, helping to prevent radiation injuries.

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.

A method using europium-doped BaFBr imaging plates (IPs) has been developed to estimate and map values of entrance skin doses during interventional radiology (IR). IPs offer many advantages for measuring the entrance skin dose because they have a wide dynamic range (up to 100 Gy), provide high spatial resolution as a detector of two-dimensional images, and can be used repeatedly. The entrance skin dose was measured by fitting a 40x40 cm IP sheet around a patient's back using a corset in clinical studies involving IR procedures at two hospitals. The corset can minimize a geometric discrepancy in dose estimates between the IP and the patient body. The entrance skin dose was measured by using photoluminescent glass dosimeters simultaneously, and both values were compared. The spatial relative dose profiles from both dose estimates showed generally good agreement; however, the doses obtained with glass dosimeter chips were often lower than those obtained with IPs. This discrepancy comes from a radiation shielding effect for x rays by IPs and a strong angular dependence of the glass dosimeter in low energy x-ray fields. Comprehensive results of this study demonstrated that IPs were able to measure entrance skin dose in even high dose regions with steep dose gradients and to determine the peak skin dose, without missing hot spots, over all ranges used during interventional radiology procedures. Use of the corset minimized variations associated with angular dependence.

We evaluated the imaging performance of a flat − panel detector digital radiography system (CXDI − 11X − ray Digital Camera ， Canon Inc ，) and a computed radiography system (FCR9000C − HQ ， Fuji Film) ． The charac − teristics of the two detectors and of the overall systems were compared ． This included evaluation and com − parison of the fundamental physical characteristics ， including x − ray response curve ， modulation transfer function (MTF) ， Wiener spectra ， noise − equivalent quanta ， and x − ray tube voltage − dependent detector response ． Overall system performance was evaluated using receiver operating characteristic (ROC) analysis ． The results of the study showed that the dynamic range of the CXDLllmeasured relative to the input x −ray flux was 1 (｝ 3 ， s ． imilar to that of the FCR9000C − HQ ． Both systems showed similar final MTFs ， aithough the pre − sampling MTF of the CXDI −11was better than that of the FCR9000C − HQ ． Noise analysis ， based on noise − equivalent quanta and Wiener spectra ， showed that for normal exposure conditions the CXDI −11had superior perfor − mance ． With both systems ， x − ray response (system output ／ incident x − ray exposure) increased with increas − ing x −ray tube voltage ． ROC analysis indicated that the CXDI − llwas superior in overall performance ．

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