Table 2.
Dosimetric constraints utilized for tomotherapy planning for pre-operative helical tomotherapy
| Index | Expected value | Definition | |
|---|---|---|---|
|
Target volume |
|
|
|
| -Planning Target Volume (PTV) |
V95 |
>95% |
Volume receiving at least 95% of prescribed dose |
| D95 |
>95% (51.3 Gy) |
Dose received by 95% of the volume |
|
| D98 |
>90% (48.6 Gy) |
Dose received by 98% of the volume |
|
| D2 |
<107% (57.8 Gy) |
Dose received by 2% of the volume corresponding to the “hot spots” |
|
| D_mean |
54 Gy |
Average dose (close as possible to the prescribed dose) |
|
|
Organs at risk |
|
|
|
| -Gastrointestinal
[9] |
D200cc |
<50 Gy |
Dose received by 200cc of the intestinal volume |
| D2 |
<54 Gy |
Dose received by 2% of the volume corresponding to the “hot spots” |
|
| V45 |
<33% |
Volume receiving 45 Gy |
|
| V20 |
<50% |
Volume receiving 20 Gy |
|
| -Contralateral kidney |
D2 |
<12 Gy |
Dose received by 2% of the volume corresponding to the “hot spots” |
| -Spinal canal | D2 | <45 Gy | Dose received by 2% of the volume corresponding to the “hot spots” |