ABSTRACT
The present work describes that we try to construct a system that collects dose information that performed CT examination from multiple facilities and unified management. The results of analysis are compared with other National diagnostic reference level (DRL), and the results are fed back to each facility and the cause of the abnormal value is investigated for dose optimization. Medical information collected 139 144 tests from 33 CT devices in 13 facilities. Although the DRL of this study is lower than that of Japan DRL, it was higher than the DRL of each country. When collecting all the examination, it is thought that the variation of the dose due to the error other than the intended imaging site is large. In future, we should continue to collect information in order to DRL renewal and we also think that it is desirable to collect information on physique and detailed scan region as well.
Subject(s)
Data Mining , Image Processing, Computer-Assisted/methods , Radiation Dosage , Radiation Exposure/standards , Radiation Monitoring/standards , Tomography, X-Ray Computed/statistics & numerical data , Tomography, X-Ray Computed/standards , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Radiation Exposure/statistics & numerical data , Radiation Monitoring/statistics & numerical data , Reference Values , Retrospective Studies , Young AdultABSTRACT
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.
