Reproducibility and Correlation of X-Ray Meters for Monitoring Scatter Radiation During Fluoroscopic Procedures

The reliability and accuracy of solid-state radiation dosimeters used during clinical procedures using pulsed low-energy x ray is uncertain.

Three test meters commonly employed in the clinical environment were assessed: the solid-state detector X2 survey meter (X2) and two personal dosimeters, the solid-state detector i3 (i3) and the Geiger-Mueller detector RadFlash (RF). Paired measurements of scatter radiation using each meter and an ion chamber meter (IC) were obtained. Meter reproducibility and the interrelationship between meters were computed. The effect of meter angulation was assessed using a special meter harness to angulate each meter from 0° to 45° from the source of scatter radiation.

Each of the test meters had good reproducibility, but the X2 and the IC had the smallest 95% confidence intervals. Each test meter had linear and close agreement with the IC, but the Geiger-Mueller-based RF meter produced higher radiation level measurements than the solid-state meters. Measured radiation dose rates at 20° and 45° angulation were significantly less than that at 0° for the solid-state meters. The effect of angulation on the Geiger-Mueller-based RF meter was only significant at 45° angulation.

These data suggest that the tested meters studied can be used to measure scatter radiation in a low-energy, pulsed fluoroscopy environment, typical of clinical imaging. Using solid-state detectors, care should be taken to avoid angulation away from the source. In addition, the modest differences in the magnitude of the measurement with each type of meter, relative to an ion chamber, should be taken into account.