Assessment of a New CT Detector and Filtration Technology: Part 1 - X-ray Beam Characterization and Radiation Dosimetry.

PURPOSE

This study evaluated beam quality and radiation dosimetry of a CT scanner equipped with a novel detector and filtration technology called PureVision Optics (PVO). PVO features miniaturized electronics, a detector cut with microblade technology, and increased filtration in order to increase x-ray detection and reduce image noise.

METHODS

We assessed the performance of two similar 320-detector CT scanners: one equipped with PVO and one without. Beam quality was measured by determining the half-value layer (HVL) and effective energy ( Eeff ) for both scanners using all tube voltages (80 kV, 100 kV, 120 kV, 135 kV) and bowtie filters (small, medium, large) available. Energy correction factors were identified for optically stimulated luminescent dosimeters (OSLDS) compared to a calibrated ionization chamber. Surface and internal doses were measured for an anthropomorphic CT angiography head phantom and a cadaver head scanned with CTDI vol matched as close as possible at the conventional (55.1 mGy) and PVO (55.4 mGy) CT scanners.

RESULTS

For all scan settings, the PVO scanner showed significantly higher HVL (range, 4.33-11.02 mm Al) and effective energy (range, 39.4-68.0 keV) values compared to the conventional scanner (HVL, 4.19-8.25 mm Al; effective energy, 38.4-55.2 keV). For equivalent CTDI vol values, the energy-corrected surface skin and lens doses were on average 6.7% lower with the PVO scanner than the conventional scanner ( P  < 0.01).

CONCLUSIONS

PVO technology yielded higher HVL and effective energies and, for the same CTDI vol , resulted in lower surface organ doses, indicating a potential for reduced patient radiation exposure in clinical settings.