Table 1.
Equivalent number of doses of radiation for most commonly requested investigations. Dose for chest x ray used as single unit dose of radiation. Figures are numbers (percentage) of doctors with correct answer for each investigation
| Radiological investigation | Equivalent No of chest x rays | No of correct answers (n=130) |
|---|---|---|
| Abdominal x ray | 75 | 2 (1.5) |
| Lumbar spine x ray | 120 | 3 (2) |
| Thoracic spine x ray | 50 | 4 (3) |
| Barium swallow | 100 | 6 (5) |
| Peroperative cholangiogram | 65 | 3 (2) |
| Fixation of fractured neck of femur | 45 | 10 (8) |
| Ultrasound of abdomen | 0 | 124 (95) |
| CT of abdomen | 400 | 8 (6) |
| Spiral CT of abdomen | 300 | 9 (7) |
| MRI of abdomen | 0 | 119 (92) |
| MRI of knee | 0 | 119 (92) |
| MRI of spine | 0 | 119 (92) |
| Leg arteriogram | 400 | 0 |
| Renal arteriogram | 80 | 1 (1) |
| Thyroid isotope scan | 50 | 8 (6) |
| White cell scan | 150 | 2 (1.5) |
CT=computed tomography; MRI=magnetic resonance imaging.