Patient and occupational dosimetry in double contrast barium enema examinations

Abstract

A new and relatively simple method is presented to distribute total dose-area product (DAP) over a number of projections that model exposure during double contrast barium enema (DCBE) examinations. In addition, hitherto unavailable entrance and effective doses to the physician performing the DCBE examination have been determined. DAP, fluoroscopy time, number of images as well as some patient data were collected for 150 DCBE examinations. For a subset of 50 examinations, the distribution of DAP over 12 hypothetical but representative projections was estimated by measuring the entrance dose in the centre of each of these projections during the complete procedure. Effective dose to the patient was obtained using DAP to effective dose conversion coefficients calculated for each of the 12 projections. Exposure of the worker was quantified by measuring the entrance dose at the forehead, neck, arms, right hand and legs. The sex-averaged effective dose to the patient per examination was 6.4+/-2.1 mSv (mean+/-SD; n=50) and the corresponding DAP was 44+/-22 Gy cm(2). The effective dose to the worker per examination was 0.52 microGy (n=50), whereas the highest entrance dose of 30+/-25 microGy was found for the right arm. The proposed method for deriving the distribution of total DAP over a set of representative projections is much less time consuming than visual observation of patient exposure, whilst accuracy seems acceptable. Entrance and effective doses per examination for workers in DCBE examinations are very low. For a normal workload, doses remain far below the legally established dose limits.

Comparison between CT Colonography and Double-Contrast Barium Enema for Colonic Evaluation in Patients with Renal Insufficiency

“…Extracolonic evaluation of CTC has also been reported to detect a considerable number of clinically important extracolonic abnormalities, including malignancies, which would not be detectable with a DCBE, even though our CTC patients happened not to have any extracolonic malignancies or abnormalities that would have precluded renal transplantation. Moreover, radiation exposure caused by a CTC in our study was a bit lower than or at the lower margin of the radiation exposure from the radiation exposure from a DCBE reported in the literature (5 to 9 mSv) (42). …”

Multi–Detector Row CT Colonography: Effect of Collimation, Pitch, and Orientation on Polyp Detection in a Human Colectomy Specimen

“…In the context of a screening program, a compromise between detection, dose, and image quality will be necessary. The results of our study suggest that a collimation of 1.25 mm, table feed of 7.5 mm (pitch of 6), and tube current of 50 mA will not degrade the detection of polyps of 5 mm or greater under ideal conditions; the effective dose for combined supine and prone scans with these parameters is 3.4 mSv, which is lower than that incurred during the acquisition of a standard abdominopelvic CT scan (6 -24 mSv) (19) or barium enema study (6.4 mSv) (20). Furthermore, one could consider increasing collimation to 2.5 mm, because a collimation of 1.25 mm resulted in the detection of only 7% more polyps of 5 mm or larger; even a modest increase in detection rate, however, could be clinically important in the context of a screening program.…”

Colonic polyps: inheritance, susceptibility, risk evaluation, and diagnostic management

“…Few studies have compared the radiation dose of CTC and DCBE 34,35. Hirofuji et al34 measured a DCBE effective dose value of 12.7 mSv (decreasing by 12% when digital radiography equipment was used), while an effective dose of CTC performed with a low-dose protocol was 5.7 mSv.…”