Large variation in radiation dose for routine abdomen CT: reasons for excess and easy tips for reduction.

OBJECTIVE: To characterize the use and impact of radiation dose reduction techniques in actual practice for routine abdomen CT. METHODS: We retrospectively analyzed consecutive routine abdomen CT scans in adults from a large dose registry, contributed by 95 hospitals and imaging facilities. Grouping exams into deciles by, first, patient size, and second, size-adjusted dose length product (DLP), we summarized dose and technical parameters and estimated which parameters contributed most to between-protocols dose variation. Lastly, we modeled the total population dose if all protocols with mean size-adjusted DLP above 433 or 645 mGy-cm were reduced to these thresholds. RESULTS: A total of 748,846 CTs were performed using 1033 unique protocols. When sorted by patient size, patients with larger abdominal diameters had increased dose and effective mAs (milliampere seconds), even after adjusting for patient size. When sorted by size-adjusted dose, patients in the highest versus the lowest decile in size-adjusted DLP received 6.4 times the average dose (1680 vs 265 mGy-cm) even though diameter was no different (312 vs 309 mm). Effective mAs was 2.1-fold higher, unadjusted CTDIvol 2.9-fold, and phase 2.5-fold for patients in the highest versus lowest size-adjusted DLP decile. There was virtually no change in kV (kilovolt). Automatic exposure control was widely used to modulate mAs, whereas kV modulation was rare. Phase was the strongest driver of between-protocols variation. Broad adoption of optimized protocols could result in total population dose reductions of 18.6-40%. CONCLUSION: There are large variations in radiation doses for routine abdomen CT unrelated to patient size. Modification of kV and single-phase scanning could result in substantial dose reduction. CLINICAL RELEVANCE: Radiation dose-optimization techniques for routine abdomen CT are routinely under-utilized leading to higher doses than needed. Greater modification of technical parameters and number of phases could result in substantial reduction in radiation exposure to patients. KEY POINTS: • Based on an analysis of 748,846 routine abdomen CT scans in adults, radiation doses varied tremendously across patients of the same size and optimization techniques were routinely under-utilized. • The difference in observed dose was due to variation in technical parameters and phase count. Automatic exposure control was commonly used to modify effective mAs, whereas kV was rarely adjusted for patient size. Routine abdomen CT should be performed using a single phase, yet multi-phase was common. • kV modulation by patient size and restriction to a single phase for routine abdomen indications could result in substantial reduction in radiation doses using well-established dose optimization approaches.

Doctor as criminal: reporting of patient deaths to the police and criminal prosecution of healthcare providers in Japan.

BACKGROUND: In Japan, medical error leading to patient death is often handled through the criminal rather than civil justice system. However, the number of cases handled through the criminal system and how this has changed in recent years has not previously been described. Our aim was to determine the trend in reports of patient death to the police and the trend in the resulting prosecution of healthcare providers for medical error leading to patient death from 1998 to 2008. METHODS: We collected data regarding the number of police reports of patient death made by physicians, next-of-kin, and other sources between 1998 and 2008. We also collected data regarding the number of resulting criminal prosecutions of healthcare providers between 1998 and 2008. Reporting and prosecution trends were analyzed using annual linear regression models. REPORTS: The number physician reports of patient deaths to the police increased significantly during the study period (slope 18.68, R2 = 0.78, P < 0.001) while reports made by next-of-kin and others did not. Mean annual reporting rates by group were physicians 130.1 (+/- 70.1), next-of-kin 29.3 (+/- 12.5), and others 10.4 (+/- 6.0). Prosecutions: The number of resulting criminal prosecutions increased significantly during the study period (slope 9.21, R2 = 0.83, P < 0.001). The mean annual prosecution rate was 61.0 (+/- 33.6). CONCLUSIONS: The reporting of patient deaths to the police by physicians increased significantly from 1998 to 2008 while those made by next-of-kin and others did not. The resulting criminal prosecutions of healthcare providers increased significantly during the same time period. The reasons for these increases are unclear and should be the focus of future research.