Patient dose due to colon examination: dose assessment and results from a survey in The Netherlands.
OBJECTIVE
To determine the effective dose to the patient during radiographic colon examination.


METHODS
The integral dose-area product was measured during colon examination in 1,733 patients aged 18-94 years. The effective dose was estimated from the dose-area product through computer simulations of radiation transport in anthropomorphic phantoms. The relation between patient dose and imaging or radiographic technique was considered. Patient dose from a biphasic colon examination was compared to that from a double-contrast examination.


RESULTS
The factors for converting dose-area product to effective dose were 0.29 mSv x Gy(-1) x cm(-2) and 0.27 mSv x Gy(-1) x cm(-2) for the biphasic and the double-contrast studies, respectively. The average dose-area product for the biphasic colon examination was 21 Gy x cm2, of which 13 Gy x cm2 was attributed to the double-contrast views. The average dose-area product was 29 Gy x cm2 (range, 18-53 Gy x cm2); the average effective dose was 4.7 mSv (range, 2.7-8.4 mSv).


CONCLUSIONS
Careful selection of the radiologic technique resulted in a surprisingly low dose during the biphasic colon examination. It is recommended that additional filtration of at least 0.1-mm copper be applied and that a screen-film combination with a speed class of at least 400 be used. Dose reduction when using digital techniques is often not realized in clinical practice.
Geleijns
J
J
Department of Clinical Oncology, University Hospital Leiden, The Netherlands.
Broerse
J J
JJ
Shaw
M P
MP
Schultz
F W
FW
Teeuwisse
W
W
van Unnik
J G
JG
Zoetelief
J
J
D000328:Adult; D000368:Aged; D001466:Barium Sulfate; D003106:Colon / Q000000981:diagnostic imaging* / Q000528:radiation effects; D003198:Computer Simulation; D003287:Contrast Media; D003625:Data Collection; D004733:Enema; D005471:Fluoroscopy; D006801:Humans; D008875:Middle Aged; D009426:Netherlands; D019047:Phantoms, Imaging; D011029:Pneumoradiography; D011829:Radiation Dosage; D011835:Radiation Protection; D011856:Radiographic Image Enhancement; D011874:Radiometry / Q000295:instrumentation; D013997:Time Factors; D014963:X-Ray Intensifying Screens
D003287:Contrast Media; D001466:Barium Sulfate