[Evaluation of patient entrance dose rate of interventional X-ray equipment]. 2003

Shigeru Miyazaki, and Shinji Abe, and Yoh Katoh, and Hiroyoshi Kobayashi, and Hideo Uehara
Department of Radiology, Ohashi Hospital, Toho University.

Because interventional radiology (IVR) procedures are being performed with increasing frequency, patient X-ray exposure dose for X-ray fluoroscopic and radiographic procedures should not be ignored. In order to avoid excessive X-ray exposure, exposure dose rate limits are specified in the Japanese Industrial Standards (JIS) and by civil law at 50 mGy/min for usual fluoroscopy and 125 mGy/min for high-dose fluoroscopy. In the present study, we examined the difference in patient incident dose rate before and after using an X-ray generator that satisfied the above requirements. For incident dose to the image intensifier (I.I.), we investigated the differences between continuous and pulsed fluoroscopy, the effects of additional filters (Ta: tantalum, Al: aluminum), and the form of the X-ray spectrum. For pulsed fluoroscopy using PMMA (polymethyl-methacrylate), the maximum patient incident dose rates of usual and high-dose fluoroscopy were 59 mGy/min and 151 mGy/min, respectively. With regard to I.I. incident dose, saturation was observed beginning at a PMMA of 20 cm, and the X-ray dose was insufficient. In terms of the difference in patient incident dose rate with Ta and Al filters, the dose rate with the Ta filter was approximately 50% lower than that with the Al filter except for the saturation area. Concerning the X-ray spectrum, it was considered that a Ta filter not only minimizes patient X-ray exposure (because Ta reduces soft X-rays more effectively than Al) but also minimizes scattered X-rays because it filters out hard X-rays, leading to improved image quality. However, the use of the filter is appropriate only when a sufficient I.I. incident dose can be ensured. Specifically, the use of the filter under saturation conditions can lead to deterioration in image quality. Therefore, IVR X-ray systems must be equipped with an appropriate filter for reducing X-ray exposure while maintaining a sufficient I.I. incident dose rate.

UI MeSH Term Description Entries
D011829 Radiation Dosage The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv). Sievert Units,Dosage, Radiation,Gray Units,Gy Radiation,Sv Radiation Dose Equivalent,Dosages, Radiation,Radiation Dosages,Units, Gray,Units, Sievert
D011835 Radiation Protection Methods and practices adopted to protect against RADIATION. Protection, Radiation
D011874 Radiometry The measurement of radiation by photography, as in x-ray film and film badge, by Geiger-Mueller tube, and by SCINTILLATION COUNTING. Geiger-Mueller Counters,Nuclear Track Detection,Radiation Dosimetry,Dosimetry, Radiation,Geiger Counter,Geiger-Mueller Counter Tube,Geiger-Mueller Probe,Geiger-Mueller Tube,Radiation Counter,Counter Tube, Geiger-Mueller,Counter Tubes, Geiger-Mueller,Counter, Geiger,Counter, Radiation,Counters, Geiger,Counters, Geiger-Mueller,Counters, Radiation,Detection, Nuclear Track,Dosimetries, Radiation,Geiger Counters,Geiger Mueller Counter Tube,Geiger Mueller Counters,Geiger Mueller Probe,Geiger Mueller Tube,Geiger-Mueller Counter Tubes,Geiger-Mueller Probes,Geiger-Mueller Tubes,Probe, Geiger-Mueller,Probes, Geiger-Mueller,Radiation Counters,Radiation Dosimetries,Tube, Geiger-Mueller,Tube, Geiger-Mueller Counter,Tubes, Geiger-Mueller,Tubes, Geiger-Mueller Counter
D005374 Filtration A process of separating particulate matter from a fluid, such as air or a liquid, by passing the fluid carrier through a medium that will not pass the particulates. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) Filtrations
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D015641 Radiography, Interventional Diagnostic and therapeutic procedures that are invasive or surgical in nature, and require the expertise of a specially trained radiologist. In general, they are more invasive than diagnostic imaging but less invasive than major surgery. They often involve catheterization, fluoroscopy, or computed tomography. Some examples include percutaneous transhepatic cholangiography, percutaneous transthoracic biopsy, balloon angioplasty, and arterial embolization. Interventional Radiography

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