Table 1.
Parameters for plan evaluation
|
PARAMETER |
Recommended | Minor Deviation† | Major Deviation† |
|---|---|---|---|
| Parameters for tumor control | |||
| Dose Prescription |
WHO grade II Simpson 1–3: 60 Gy |
- |
>60 Gy or <60 Gy |
| WHO grade III or Simpson 4–5: 70 Gy |
- |
<70 Gy or >70 Gy |
|
| Dose Conformity |
PTV D95% ≥ 95% of the prescribed dose |
PTV D95% = 90 – 94% of the prescribed dose |
PTV D95% < 90% of the prescribed dose |
| Target Volume Delineation |
PTV covers all CTV and GTV |
- |
GTV and CTV outside the PTV* |
| CTV covers all GTV |
- |
GTV outside the CTV |
|
| GTV to CTV margin |
10 mm |
11-15 mm |
>15 mm |
|
Parameters for normal tissue toxicity | |||
| PTV D2% (Gy) |
<107% of the prescribed dose |
107-110% of the prescribed dose |
>110% of the prescribed dose |
| Brainstem D2% or D0.5cc (surface) |
<64 Gy |
64-65 Gy |
>65 Gy |
| Brainstem D2% or D0.5cc (center) |
<54 Gy |
54–55 Gy |
>55 Gy |
| Optic Chiasm/Nerve D2% |
<60 Gy |
60-61 Gy |
>61 Gy |
| Cochlea D2% | <50 Gy | 50-51 Gy | >51 Gy |
* PTV for dose evaluation may be restricted to 5 mm below the patient outer contour. † Cases with both major and minor deviations were considered as with major deviation in overall analyses.
Abbreviations: PTV, Planning Treatment Volume; CTV, Clinical Target Volume; GTV, Gross Tumor Volume; D95%, D2%, Dose received by 95 and 2 percent of the volume, respectively; D0.5cc, Dose received by 0.5 cc of the volume.