Radiation Dose from Computed Tomography in Patients with Necrotizing Pancreatitis: How Much Is Too Much?
Chad G. Ball*, Camilo Correa-Gallego, Thomas J. Howard, Nicholas J. Zyromski, Michael House, Henry a. Pitt, Attila Nakeeb, C. Max Schmidt, Keith D. Lillemoe
Surgery, Indiana University, Indianapolis, IN
Objectives: Low-dose ionizing radiation from medical imaging has been indirectly associated with the subsequent development of solid cancers and leukemia. The non-invasive, gold standard modality for defining the initial extent, as well as the evolution of pancreatic necrosis is computed tomography (CT). The goals of this study were to identify: (1) the frequency of CT imaging, (2) the effective radiation dose per patient, (3) the rate of therapeutic intervention following CT, and (4) the mean direct hospital cost for these patients.Methods: All patients with necrotizing pancreatitis (2003-2007) treated at a tertiary care referral center were retrospectively analyzed. Standard statistical methodology was employed (significance = p<0.05).Results: Of the 1290 patients with acute pancreatitis, 238 (18%) were necrotizing (mean age = 53 years, hospital/ICU lengths of stay = 23/7 days, mortality = 9%). A median of 5 CT scans per patient (range = 1 to 28) were performed during the mean 8.3 month imaging interval. The average effective dose was 40 mSv per patient. This dose is equivalent to 2000 chest x-rays or 13.2-years of background radiation or a 1/250 increased risk of fatal cancer. Twenty percent of CT scans were followed by a direct intervention (199 interventional radiology, 118 operative, 12 endoscopic)(median = 1; range = 1 to 7) or change in management. This proportion increased to 31% in physiologically ill patients (p<0.05). MRI use did not have a CT-sparing effect (p>0.05). The modality of intervention did not alter the total number of, or the time intervals between, CT scans (p>0.05). Mean direct hospital costs increased in a stepwise manner parallel to the number of CT scans (R=0.7, p<0.05).Conclusions: The effective radiation dose received by patients with necrotizing pancreatitis is significant. Changes in management following individual CT scans occur in a minority of patients (20% to 31%). The ubiquitous use of CT imaging in necrotizing pancreatitis raises substantial public health concerns and mandates a careful reassessment of its utility.
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