The comparison of radiation dose between C-arm flat-detector CT (DynaCT) and multi-slice CT (MSCT): a phantom study.

PURPOSE

To assess and compare the radiation dose of DynaCT in phantoms to that of MSCT.

METHODS AND MATERIALS

A male Anderson Radiation Therapy 200 phantom with embedded thermoluminescence dosimeters (TLDs) was scanned with DynaCT (Axiom Artis dTA, Siemens Healthcare, Forchheim, Germany) and MSCTs (MSCT1: Lightspeed VCT, GE, Milwaukee, USA; MSCT2: Sensation Cardiac 64, Siemens Healthcare, Erlangen, Germany), respectively. For DynaCT, radiation exposure data with automatic exposure control were obtained from scanning of head, chest and abdomen. For MSCT, scanning protocols for head, chest, and abdomen were examined under conventional exposure conditions. Effective doses were calculated from LiF-TLD measurements according to ICRP103. A Catphan phantom (Phantom Lab, USA) was used to evaluate the spatial resolution and low contrast detectability of DynaCT and MSCT.

RESULTS

The effective doses for DynaCT from head, chest and abdomen scanning were 1.18, 7.32, 7.48 mSv (20 s scan) and 0.85, 6.01, 7.04 mSv (8 s scan); the effective doses for MSCT from head, chest and abdomen scanning were 3.33, 7.62 and 8.42 mSv (MSCT1), and 1.89, 7.52, 8.23 mSv (MSCT2). Significant difference between the organ doses from DynaCT and from MSCT (p<.05) was shown. The spatial resolution of 12 lp/cm was achieved and it was able to recognize a 3mm low contrast object at 0.5% contrast level in DynaCT, which was on the same level as in the MSCT images.

CONCLUSION

The phantom study indicates that DynaCT applies significantly less dose to patient and achieves similar spatial resolution and low contrast detectability to standard diagnostic MSCT.