Table 1.
Categories of failure for IROC lung and SBRT spine phantom irradiations from Jan 2012 – Dec 2018, along with head and neck phantom failure data from a previous IROC study[5] (Nov 2014 – Oct 2015).
| Error Type | Number of phantoms (%) | 95% C.I. (%) |
|---|---|---|
| Lung | ||
| Systematic dose | 28 (22%) | (17,33) |
| ➣ overdose | 9 (6%) | |
| ➣ underdose | 19 (16%) | |
| Local dose | 7 (6%) | (3, 12) |
| Localization: major motion | 64 (50%) | (46,64) |
| ➣ superior | 26 (20%) | |
| ➣ inferior | 38 (30%) | |
| Localization: minor motion (ant-post) | 8 (6%) | (4,13) |
| Localization: no motion (left-right) | 7 (6%) | (3,12) |
| Global | 3 (2%) | (1,7) |
| Combination category | 10 (8%) | (5,15) |
| Spine | ||
| Systematic dose | 25 (60%) | (44,73) |
| ➣ overdose | 9 (22%) | |
| ➣ underdose | 16 (38%) | |
| Dose fall-off region | 5 (12%) | (5,25) |
| OAR overdose | 6 (14%) | (7,28) |
| Localization | 6 (14%) | (7,28) |
| Head and Neck [5] | ||
| Systematic dose | 32 (62%) | (48,74) |
| ➣ overdose | 6 (12%) | |
| ➣ underdose | 26 (50%) | |
| Local dose | 8 (15%) | (8,28) |
| Localization | 6 (12%) | (5,23) |
| Global | 6 (12%) | (5,23) |