Dose Uniformity Analysis Among Ten 16-Slice Same-Model CT Scanners:

A quality improvement project for reducing cardiac computed tomography radiation dose in a community-based, multihospital setting

Radiation associated with computed tomography coronary angiography (CTCA) is a persistent concern. Strategies for reducing radiation exposure have been described, primarily in academic settings. We developed a standard protocol for CTCA acquisition focused on radiation reduction strategies in a community-based, multihospital setting and hypothesized that the protocol would be effective at reducing radiation in this setting. The protocol included the use of body mass index based tube voltage adjustment and routine use of prospective electrocardiographic gating with either dose modulation or step-and-shoot acquisition. Data on radiation exposure were collected retrospectively and compared by nonparametric testing. Some hospitals failed to routinely record radiation exposure data; only 2 facilities had data available from both before and after the intervention for direct comparison. Data were acquired from 124 subjects, 41 from the standard of care group and 83 scanned under the new protocol. In hospital A, radiation was significantly reduced by 61% from 20.5 ± 4.6 millisieverts (mSv) to 7.9 ± 4.8 mSv (P < 0.001). Within the new protocol group for hospital A, radiation was lower with step-and-shoot (4.0 ± 1.5 mSv) as compared to dose modulation (10.2 ± 4.2 mSv, P < 0.001). In hospital B, which already employed step-and-shoot acquisition, radiation dose was reduced 16% from 9.3 ± 3.0 mSv to 7.9 ± 2.2 mSv (P < 0.017) by applying body mass index-based tube voltage adjustment alone. In conclusion, a minimal investment in institutional resources can result in a reduction in radiation exposure from CTCA, even in a community-based, multihospital setting. Some facilities do not routinely record radiation exposure data.