A Community Hospital's Experience With an Effective, Affordable, and Easily Implemented CT Radiation Dose Reduction Initiative

Assessment of radiation dose from abdominal quantitative CT with short scan length

OBJECTIVE

To assess radiation dose for patients who received abdominal quantitative CT and to compare the midpoint dose [D_L(0)] at the centre of a 1-cm scan length with the volume CT dose index (CTDI_vol). Although the size-specific dose estimate (SSDE) proposed in The American Association of Physicists in Medicine Report No. 204 is not applicable for short-length scans, commercial dose-monitoring software, such as Radimetrics^™ Enterprise Platform (Bayer HealthCare, Whippany, NJ), reports SSDE for all scans. SSDE was herein compared with D_L(0).

METHODS

Data were analyzed from 398 abdominal quantitative CT examinations in 165 males and 233 females. The CTDI_vol was 4.66 mGy, and the scan length was 1 cm for all examinations. Radimetrics was used to extract patient diameter and SSDE. D_L(0) was assessed using a previously reported method that takes into account both patient size and scan length.

RESULTS

The mean patient diameter was 28.5 ± 6.3 cm (range, 16.5-46.6 cm); the mean SSDE was 6.22 ± 1.36 mGy (range, 3.12-9.42 mGy); and the mean D_L(0) was 2.97 ± 0.95 mGy (range, 1.18-5.77 mGy). As patient diameter increased, the D_L(0) to CTDI_vol ratio decreased, ranging from 1.24 to 0.25; the D_L(0) to SSDE ratio also decreased, ranging from 0.61 to 0.38.

CONCLUSION

The dose to the patients from abdominal quantitative CT may be largely different from CTDI_vol and SSDE. This study demonstrates the necessity of taking into account not only patient size but also scan length for evaluating the dose from short-length scans. Advances in knowledge: In CT examinations with 1-cm scan length, dose evaluation needs to take into account both patient size and scan length. An omission of either factor can result in an erroneous result.

Optimizing CT Pulmonary Angiogram Utilization in a Community Emergency Department: A Pre- and Postintervention Study

PURPOSE

Optimizing the utilization of CT pulmonary angiogram (CTPA) for the diagnosis and workup of acute chest pain can provide an opportunity to reduce unnecessary radiation and health care system expense.

METHODS

An attempt to improve CTPA utilization began by measuring overall department and clinician-specific utilization. This was bolstered by retrospectively evaluating patient charts for pulmonary embolism scoring criteria and D-dimer utilization so as to better understand gaps in diagnostic workup. The department-wide and individualized metrics were then provided to each emergency department clinician and differences between the pre- and postintervention data were evaluated.

RESULTS

The percentage of positive CTPAs did not change significantly at 8.7% and 9.2% in the pre- and postintervention groups, respectively. Similarly, the workup of patients based on retrospective PERC and Wells-score criteria did not significantly improve after the intervention. However, the percentage of CTPAs ordered on low D-dimer patients did decrease significantly post-intervention. Further observational analysis uncovered marked variability in clinician ordering behavior and diagnostic rates.

CONCLUSIONS

Overall, such an intervention seems to have a limited, though not insignificant, impact on the workup of suspected pulmonary embolism. Calculating provider-specific utilization metrics allows both the radiologist and clinician to better understand opportunities to improve health care delivery.

A Comprehensive CT Dose Reduction Program Using the ACR Dose Index Registry

PURPOSE

The purpose of this article is to demonstrate the role of the ACR Dose Index Registry(®) (DIR) in a dose reduction program at a large academic health care system.

METHODS

Using the ACR DIR, radiation doses were collected for four common CT examination types (head without contrast, chest with contrast, chest without contrast, and abdomen and pelvis with contrast). Baseline analysis of 7,255 CT examinations from seven scanners across the institution was performed for the period from December 1, 2011, to March 15, 2012. A comprehensive dose reduction initiative was guided by the identification of targets for dose improvement from the baseline analysis. Data for 14,938 examinations from the same seven scanners were analyzed for the postimplementation period of January 1, 2013, to July 1, 2013.

RESULTS

The program included protocol changes, iterative reconstruction, optimization of scan acquisition, technologist education, and continuous monitoring with feedback tools. Average decrease in median dose-length product (DLP) across scanners was 30% for chest CT without contrast, 29% for noncontrast head CT, 26% for abdominal and pelvic CT with contrast, and 10% for chest CT with contrast. Compared with average median DLP in the ACR DIR, the median institution-wide CT DLPs after implementation were lower by 33% for chest CT without contrast, 32% for chest CT with contrast, 26% for abdominal and pelvic CT with contrast, and 6% for head CT without contrast.

CONCLUSIONS

A comprehensive CT dose reduction program using the ACR DIR can lead to substantial dose reduction within a large health care system.