Mean Radiation Absorbed Doses to Xenografts from 3-Cycle Pretargeted 177Lu-DOTA-Bn Based on Serial SPECT Imaging
| Cycle 1 | Cycle 2 | Cycle 3 | ||||
| Mouse | Dose 0–160 h (Gy) | Cumulative dose (Gy) | Dose 160–320 h (Gy) | Cumulative dose (Gy) | Dose 320–480 h (Gy) | Cumulative dose (Gy) |
| 1 | 29.1 | 32.8 | 43.5 | 96.0 | 27.7 | 102 |
| 2 | 21.7 | 24.7 | 55.5 | 104 | 37.7 | 117 |
| 3 | 25.9 | 35.4 | 34.6 | 77.4 | 25.4 | 87.5 |
| 4 | 19.9 | 24.4 | 39.9 | 75.7 | 26.1 | 87.4 |
| 5 | 33.4 | 35.8 | 45.3 | 102 | 32.8 | 114 |
| Mean | 26.0 | 30.6 | 43.8 | 91.0 | 29.9 | 102 |
| SD | 5.5 | 5.7 | 7.7 | 13.5 | 5.2 | 14.1 |
| Coefficient of variation | 21% | 18% | 18% | 15% | 17% | 14% |
Tumors were estimated to be below palpation threshold at 496 h after injection of cycle 1, thus having an effective activity concentration of zero. Cumulated dose for each cycle was calculated as total dose after 496 h after injection of cycle 1, assuming treatment was stopped at that dose. Therefore, cycle 2 cumulated dose represents expected dose after 496 h from a treatment comprising only 2 cycles. Dose during the third period was calculated from 320 to 480 h to be comparable in duration to the other 2 periods. In fact, the period after injection of cycle 3 until complete regression of tumor is slightly longer than the other 2 cycle periods.