Table 2.
MRT Parameters Eliciting Normal Tissue Tolerance.
| Animal | Tissue | Microbeam | Pathology | Threshold Peak-Dose (Gy) | Valley-Dose (Gy) | |
|---|---|---|---|---|---|---|
| Width (µm) | Spacing (µm) | |||||
| Duck [67] | Immature CNS | 27 | 100 | Ataxia | 160 | NR |
| Rat [15] | Brain | 27 | 75 | Necrosis, oedema | 250 | 17 |
| 27 | 100 | 500 | 33 | |||
| Rat [73] | Brain | 27 | 200 | Cell loss, demyelination | 1000 | NR |
| Rat [25] | Brain | 25 | 100 | Tissue damage (loss of tissue structure; vascular damage) | 625 uni- & bidirectional | NR |
| 312 bidirectional | ||||||
| Rat [65] | Spinal cord | 35 | 210 | Paresis/Paralysis (over 383 dpi) | 357 (19mm transverse depth) | 12.7 |
| Mouse [72] | Brain | 25 | 211 | Damage to microvasculature/vasogenic oedema (up to 1 mpi) | 312–1000 | 5.8 |
| Rat (11–13 day old) [26] | Brain | 28 | 105 | Neurological dysfunction | 150 | >5 Gy [69] |
| 28 | 105 | 50 | ||||
| 25 | 210 | 300 bidirectional | ||||
| Piglet [66] | Brain | 20–30 | 210 | Neurological function (465 dpi) | 600 peak-entry 263 @ cerebellum |
12.6 @ cerebellum |
| Rat [18] | Brain | 20 | 200 | Necrosis (14 dpi) | 5000 | NR |
| 37 | 75 | Tissue damage (14–31dpi) | 625 | |||
| 20 | 200 | Loss of nuclei (30-31dpi) | 2000 | |||
| 37 | 75 | |||||
| Skin | 37 | 200 | Epilation (2–4 weeks dpi) | 1250–2500 | ||
| 37 | 75 | 1250–2500 | ||||
| Mouse [74] | Brain | 25 | 211 | Cerebral oedema (up to 28 dpi) | <1000 | 10.5 |
| Mouse [49] | Skin | 90 | 300 | Moist desquamation | 1740 co-planar | 35 |
| 650 cross-planar | 26 | |||||
| Mouse [76] | Skin | 90 | 300 | Moist desquamation | 1005-1170 | 14-17 |
| Mouse [83] | Abdomen | 25 | 400 | GI syndrome | 249 (257 TD50) | 7.5 (7.7) |
| Head | Neurological dysfunction | 255 (268 TD50) | 6.8 (7.2) | |||
| Thorax | Neurological dysfunction, pulmonary damage | 391 (lowest administered dose) | 9.5 | |||
| Total body | Weight loss, moribund behaviour | 88.9 (120 TD50) | 2.8 (3.8) | |||
| Mouse [75] | Saphenous artery | 50 | 400 | Functional deficits, atrophy, arterial damage | 2000 | 17.6 |
| Rat [34] | Brain | 50 | 211 | Neurological dysfunction | 480 | 18 |
| Mouse [79] | Testes (ex vivo) | 50 | 100 | Spermatogenesis | 5 | NR |
| Rat [68] | Brain (+eye) | 25 | 211 | Retinal degeneration (12 dpi) | 350 * (bidirectional) | NR |
| Rat [45] | Brain (+eye) | 25 | 200 | Optic nerve damage | 350 * (bidirectional) | NR |
Threshold Peak-Dose: indicates the highest peak-dose (skin entry or at indicated tissue depth) reported that did not result in pathology in the majority of animals. Note: studies testing only one dose are indicated by an asterisk (*). NR: Not-Reported.