Challenges experienced in establishing clinical indication based diagnostic reference levels: Pilot study

Establishment of local diagnostic reference levels for abdomen and chest radiographies in the region of Algarve, Portugal

PURPOSE

To assess doses variabilities in the same abdomen and chest RX exams for adults, to check the need for dose harmonization. To calculate Diagnostic Reference Levels (DRL), mandatory in the European Union, for the Algarve district in Portugal. Our results can be a valuable reference for the Portuguese official determination of DRLs, still in progress.

METHOD

We considered 4,936 abdomen and 41,320 chest radiographs of adults, covering 7 health centres and 35 radiographers in Algarve. Entrance skin dose (ESD) was calculated for each radiograph and the corresponding uncertainty estimated. Mean doses per centre and per technician, and their uncertainties, were calculated to access dose variabilities. DRLs, set at the 3rd quartile of the total ESD distribution, were determined for a standard patient and for intervals of body mass index (BMI) to study their correlation with patient anatomical variations. Standard quartile errors were estimated.

RESULTS

Our results suggest significant dispersion in applied ESDs among different centres and radiographers. Estimates of DRLs also show small fluctuations across years and an important dependence on BMI intervals. For a standard patient, they are 8.7 ± 0.1 (abdomen) and 0.44 ± 0.01 (chest), while the European DRLs are, respectively, 5.1 and 0.2 (all in mGy).

CONCLUSIONS

Results suggest that there is room for dose optimization and harmonization with European DRLs, urging a national dose survey and the establishment of official national DRLs. Official DRLs in intervals of BMI would be quite beneficial, to avoid unnecessary dose exposures.

Establishing Protocol-based Dose Metrics for Common Abdomen and Pelvis Computed Tomography Protocols

BACKGROUND AND AIM

The majority of the existing diagnostic reference levels (DRLs) that have been established for computed tomography (CT) are based on various anatomical locations, such as the head, chest, abdomen, etc. However, DRLs are initiated to improve radiation protection by conducting a comparison of similar examinations with similar objectives. The aim of this study was to explore the feasibility of establishing dose baselines based on common CT protocols for patients who underwent enhanced CT abdomen and pelvis exams.

METHODS

Dose length product total (tDLPs), volumetric CT dose index (CTDIvol), size-specific dose estimate (SSDE), effective dose (E), and scan acquisition parameters for a total of 216 adult patients, who underwent an enhanced CT abdomen and pelvis exams over a one-year period, were obtained and retrospectively analyzed. Spearman coefficient and one-way ANOVA tests were used to check significant differences between dose metrics and the different CT protocols.

RESULTS

The data exhibited 9 different CT protocols to acquire an enhanced CT abdomen and pelvis exam at our institute. Out of these, 4 were found more common, i.e., CT protocols were acquired for a minimum of 10 cases. Triphasic liver demonstrated the highest mean and median tDLPs across all 4 CT protocols. Triphasic liver protocol registered the highest E followed by gastric sleeve protocol with a mean of 28.7 and 24.7 mSv, respectively. Significant differences (p < 0.0001) were found between the tDLPs of anatomical location and the CT protocol.

CONCLUSION

Evidently, wide variability exists across CT dose indices and patient dose metrics relying on anatomical-based dose baseline, i.e., DRLs. Patient dose optimizations require establishing dose baselines based on CT protocols rather than the anatomical location.

Challenges Associated with Effective Implementation of CT Dose Check Standards and Radiation Monitoring Index in Computed Tomography: Healthcare Sector Experience

Computed tomography (CT) radiation dose management tools should be used whenever possible, particularly with the increasing demand for acquiring CT studies. Herein, we aim to assess the advantages and challenges faced with implementing two CT dose management tools. A second aim was to highlight CT examinations exceeding dose notification values (NVs) and define the common set of causes. A total of 13,037 CT examinations collected over a six-month period, were evaluated, using two independent CT dose management tools, a CT Dose Notification prospective-view tool (PVT) following CT Dose Check standards and a retrospective statistical-based view tool (RSVT). Dose NVs were set to twice the Local Diagnostic Reference Levels. There was a significant discrepancy between dose NV counts registered with prospective (4.15%) and retrospective (7.98%) tools using T-Test. A core difference is the dose configuration setup, with PVT and RSVT being dose per series and whole study, respectively. Both prospective and retrospective dose management tools were equally useful despite their technical difference. Configuring the CT prospective dose notification check tool using NVs that is based on DRLs has limitations, and one needs to establish dose NVs per series to overcome this technical hurdle. Technical challenges make the implementation of CT Dose Check standards puzzling.