The Joint Commission requires institutions to consider a patient’s imaging history when determining the appropriateness of an imaging exam to avoid unnecessary duplication of studies. Radiation dose management software offers new opportunities to retrospectively identify patients who have undergone a large number of studies or who may have accumulated a large value of effective dose and review their imaging history to determine if recurrent CT exams occurred. Therefore, the purpose of this work was to use a radiation dose management system to retrospectively identify patients with high cumulative dose and/or large number of CT exams as a cohort in whom a detailed review of their imaging history was performed to identify recurrent CT Exams.
METHODSUsing Radimetrics a total of 72073 CT examinations performed from Jan 2015 to Jan 2016 were studied to categorize patients with a cumulative effective dose of 100 mSv and above as well as highest number of CT examinations. Imaging histories of 20 patients (10 in each category) with highest cumulative dose and highest number of exams were further investigated by three radiologists for appropriateness of recurrent studies and potential opportunities for reducing the number of imaging studies and doses. The review process for each patient’s imaging history was timed to assess the feasibility of a larger scale review study.
RESULTSOut of 34762 patients, 2.7% were identified with a cumulative dose of 100 mSv and above. The 10 patients with the cumulative dose had values that ranged from 376 to 842 mSv, while the 10 patients with the largest number of CT examinations ranged from 25 to 55 CT exams. Most patients in the highest cumulative dose category were oncology patients who had undergone ablation procedures, while most patients in the largest number of examinations group were head trauma patients. An imaging history review of these patients only identified two possible CT scan that could have been avoided. As per radiologist’s review, one of the scan was performed to assess liver transplant vessel patency, which may be more appropriately assessed with ultrasound as the initial imaging modality. Additionally, a technical factor analysis identified certain CT guided interventional protocols where dose reduction could be achieved by simply using lower mAs values for repeated scans that can tolerate lower image quality. Radiologists reported an average of 20 min per patient for their review process.
CONCLUSIONWith the introduction of dose management software, institutions now have access to heretofore untapped patient dose data that can be analyzed for opportunities to improve clinical practice. Retrospective review of all exams for appropriateness can be challenging, is time consuming and presents a difficult, ongoing problem for the institution.Analysis of the root causes of large numbers of scans or a large number of high dose scans can be very complicated and difficult to discern given clinical practices. During our Investigation we learned valuable lessons that are not necessarily obvious or not openly discussed and worth sharing with others. In our analysis, we investigated patients with the highest cumulative dose and highest number of examinations. Usually these patients are critically ill patients who cannot be evaluated by just knowing their history and performing physical exams due to being intubated and sedated; others are patients with advanced staged cancer who need periodic restaging scans and in some cases frequent CT guided ablation procedures to improve quality of life. The probability of coming across any scans that could have been avoided among these kinds of patients is very low, not only because of their physical status, but also because transporting these patients to the radiology department can be challenging. Such scans are therefore not usually ordered unless absolutely necessary. Future studies should carefully select patient populations to be reviewed separate from the population of severely ill patients and oncologic patients. Future studies may focus on a specific CT procedure, or a specific patient population.There are still lessons learned in this study that can be implemented to reduce radiation dose. Although most of reviewed patients were extremely ill patients, scans performed to check for positioning of tubes and devices can be performed at lower mAs values. Reducing radiation dose should be a common practice regardless of patient’s prognosis. Additionally, the review process itself has suggested areas for potential improvement in patient care, including improved documentation and Radiologist involvement in patient management. Under ideal circumstances radiologists would protocol all ordered studies and decide on the most appropriate type of imaging exam, but in many current practices the volume and workflow demands are such that occasionally indications that may have been better assessed by a different modality slip through and are inadvertently performed.