[en] As interventional radiology (IVR) has advanced and spread in recent years, fear of the increased possibility of radiation exposure of the patient and the staff has grown. Radiation exposure may be increased by the following factors: (1) increasing numbers of patients treated with IVR following development of new IVR techniques and expansion of the indications for their application; and (2) prolongation of fluoroscopy time required by advanced and complex IVR techniques. An example of such a change is found in transcatheter arterial embolization (TAE). With earlier TAE techniques, embolization was often performed via he proper hepatic artery. Recently during TAE a microcatheter is inserted beyond the subsegmental artery into the peripheral branch so that catheterization to a point near each tumor, even in the case of multiple tumors, can be achieved. These recent IVR techniques are advantageous for the patient in terms of therapeutic efficacy, but it is evident that these techniques increase that exposure of radiological staff members to radiation. At our facility, the average duration of fluoroscopy for vascular IVR (excluding cardiac catheterization) was 37.5 minutes per patient in 1997. This is more than double the time needed when angiography is used for diagnostic purposes (14.5 minutes on average). Among them, fifty-one cases (7.2%) required 60-minute or longer fluoroscopy and 6 cases (0.85%) required 120-minute or longer fluoroscopy. IVR techniques which required prolonged fluoroscopy were TAE for hepatocellular carcinoma, percutaneous catheter placement for metastatic liver cancer, PTA, aortic stent grafting, and TIPS. An experiment using phantoms showed that fluoroscopy using an over-the-table X-ray tube for 30 minutes cased approximately 1 mSv exposure of the eye lens. This means that the lenses of a interventionalist who performs a number of IVRs may be exposed to more than 150 mS/year. This is why it is necessary for the interventionalist to wear protective glasses when using an over-tube type fluoroscopy. At our facility, the over-tube type device is seldom used, even for non-vascular IVR. The apparatus used at our facility for DSA (digital subtraction angiography) has recently been equipped with a device which always displays the tota radiation dose (fluoroscopy + film acquisitions). To avoid excessive exposure of radiological staff members involved in IVR, the use of this kind of protective device should be accompanied by the following efforts: (1) to shorten the duration of fluoroscopy, (2) to take a distance from the source of radiation, and (3) to use the collimation frequently. (author)