Table 3. Changes in Mean Dose After Interventions by Anatomical Area for Effective Dose, CTDIvol, and Organ Dosea.
| Variable | Mean Dose Before Intervention, mSv | After Intervention | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Audit Alone | Multicomponent Intervention | ||||||||
| Mean Dose After Audit | Change in Mean Dose (95% CI), mSv | Change, % | P Value | Mean Dose After Complex Intervention | Change in Mean Dose (95% CI), mSv or mGy | Change, % | P Value | ||
| Effective dose, mSv | |||||||||
| Abdomen | 14.7 | 14.6 | −0.13 (−0.24 to −0.02) | −1 | .02 | 13. 9 | −0.81 (−0.99 to −0.64) | −6 | <.001 |
| Chest | 7.1 | 7.0 | −0.14 (−0.23 to −0.05) | −2 | .002 | 6.8 | −0.26 (−0.40 to −0.11) | −4 | <.001 |
| Chest and abdomen | 14.9 | 14.0 | −0.88 (−1.18 to −0.57) | −6 | <.001 | 12.9 | −2.04 ( −2.55 to −1.53) | −14 | <.001 |
| Head | 1.7 | 1.7 | −0.01 (−0.06 to 0.04) | −1 | .68 | 1.7 | −0.05 (−0.13 to 0.02) | −3 | .18 |
| Organ doses, mGy | |||||||||
| Abdomenb | 62.6 | 56.6 | −6.0 (−6.9 to −5.0) | −10 | <.001 | 50.4 | −12.2 (−13.8 to −10.6) | −20 | <.001 |
| Chestc | 29.3 | 27.2 | −2.1 (−2.8 to −1.5) | −7 | <.001 | 25.6 | −3.7 (−4.7 to −2.7) | −13 | <.001 |
| Chest and abdomenc | 70.7 | 54.7 | −16.0 (−18.2 to −13.8) | −23 | <.001 | 40.6 | −30.1 (−33.8 to −26.4) | −43 | <.001 |
| Chest and abdomenb | 42.1 | 29.1 | −13.0 (−14.5 to −11.6) | −31 | <.001 | 24.5 | −17.6 (−20.0 to −15.1) | −42 | <.001 |
| Headd | 89.3 | 86.4 | −2.9 (−6.4 to 0.70) | −3 | .11 | 81.8 | −7.5 (−13.3 to −1.7) | −8 | .01 |
| CTDIvol, mGy | |||||||||
| Abdomen | 14.7 | 14.8 | 0.09 (0.01 to 0.16) | 0.6 | .03 | 14.7 | 0.03 (−0.10 to 0.15) | 0.2 | .68 |
| Chest | 11.6 | 11.6 | 0.04 (−0.07 to 0.14) | 0.3 | .50 | 11.5 | −0.11 (−0.29 to 0.06) | −1 | .20 |
| Chest and abdomen | 10.7 | 10.7 | −0.05 (−0.18 to 0.08) | −0.4 | .48 | 10.3 | −0.42 (−0.64 to −0.20) | −4 | <.001 |
| Head | 38.6 | 39.0 | 0.44 (0.27 to 0.62) | 1.1 | <.001 | 38.0 | −0.56 (−0.85 to −0.27) | −1 | <.001 |
Abbreviations: CTDIvol, volume computed tomographic dose index; mGy, milligrays; mSv, millisieverts.
a
Results are after audit alone and after complex multicomponent intervention relative to before intervention adjusting for temporal trends and patient and facility characteristics by anatomical area.
b
Colon organ doses.
c
Lung organ doses.
d
Brain organ doses.