Table 5.
Preshielding peripheral dose in the region of the umbilicus, expressed as a percentage of the monitor units and as a percentage of the prescribed dose.
| Collimator size (mm) | Distance (cm) | Preshielding peripheral dose (cGy) | Preshielding peripheral dose (%MU) | Preshielding peripheral dose (%TD) | Monitor units | Prescribed dose (cGy) | Isodose line (%) |
|---|---|---|---|---|---|---|---|
| 12.5 | 58 | 2.15 | 0.05 | 0.11 | 4005 | 2000 | 84 |
| 10 | 58 | 2.83 | 0.05 | 0.14 | 5587 | 2000 | 75 |
| 20, 20, 20 | 62 | 7.67 | 0.07 | 0.38 | 11374 | 2000 | 75 |
| 5, 5, 5 | 59 | 11.64 | 0.06 | 0.58 | 18026 | 2000 | 75 |
| 7.5, 7.5, 15 | 59 | 12.62 | 0.06 | 0.70 | 20487 | 1800 | 79 |
| 10, 10, 15 | 58 | 16.00 | 0.07 | 0.64 | 23876 | 2500 | 75 |
| 20, 20, 20 | 55 | 19.35 | 0.08 | 0.77 | 25794 | 2500 | 67 |
| 5, 5, 5 | 56 | 17.40 | 0.06 | 0.97 | 27433 | 1800 | 76 |
| 7.5, 7.5, 15 | 55 | 16.68 | 0.06 | 0.93 | 28411 | 1800 | 75 |
| 7.5, 15, 25 | 50 | 26.75 | 0.07 | 1.07 | 39476 | 2500 | 70 |
MU: Monitor Units
TD: Prescribed Dose