Differences in effective dose estimation from dose-area product and entrance surface dose measurements in intravenous urography.
In this study, measurements of dose-area product (DAP) and entrance surface dose (ESD) were carried out in a sample of 25 adult patients who underwent intravenous urography (IVU). These measured quantities were used to estimate the effective dose E from the IVU examination, a quantity closely correlated to radiation risk. Estimating E involves the use of conversion coefficients that have been determined for specific X-ray views in a mathematical phantom. These are obtained under conditions which are not usually met in clinical practice. As a result, the E estimates using the two different measurable quantities can be quite different. Analysis of the calculation procedure suggests that the E estimate using the DAP measurements, in addition to being more practical, could be more accurate than using ESD measurements, as DAP is sensitive to the X-ray field size settings. Furthermore, it is shown that in the absence of the appropriate equipment, a reliable E estimate can be obtained from the ESD calculated using the exposure data for each X-ray view.
Yakoumakis
E
E
Medical Physics Department, Medical School, University of Athens, 75 Mikras Asias, 115 27 Athens, Greece.
Tsalafoutas
I A
IA
Nikolaou
D
D
Nazos
I
I
Koulentianos
E
E
Proukakis
C
C
D000328:Adult; D002138:Calibration; D005260:Female; D006801:Humans; D008297:Male; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods; D012867:Skin / Q000528:radiation effects; D014567:Urography