Table 1 Summary of the quantitative analysis of the dose volume histograms for the target volume (CTV) and the organs at risk. Included also the data relative to the coverage of the virtual target expansions of 2 and 5 mm. In brackets the upper limit of the constraints. The comparator data derives from brachytherapy treatments. In the objective’s column, the values in brackets correspond to the upper hard limit for the corresponding metrics. The ranges are reported in square brackets
| Structure | Parameter | Objective | SFRT_1 | SFRT_2 | SBRT | Comparator |
|---|---|---|---|---|---|---|
| CTV | D90% | 30 Gy | 30 | 30 | 30 | – |
| V45Gy (150%) | ≥ 50–55% |
43.1 ± 7.5 [33.0,55.9] |
56.6 ± 5.6 [45.4,64.8] |
2.3 ± 3.8 [0,10.6] |
61.0 ± 3.8 [56.0,66.4] | |
| V60Gy (200%) | ≥ 30% |
15.4 ± 5.6 [6.9,23.9] |
26.8 ± 6.6 [17.3,34.2] |
0 [0,0] |
37.2 ± 3.6 [31.6,41.8] | |
| PTV2mm | D90% | 30 Gy |
23.2 ± 1.3 [21.0,24.5] |
23.4 ± 1.7 [21.1,24.7] |
23.1 ± 1.1 [21.5,24.3] | – |
| PTV5mm | D90% | 30 Gy |
20.0 ± 1.4 [19.0,21.8] |
22.6 ± 2.1 [17.4,22.2] |
19.9 ± 1.1 [17.9,26.2] | – |
| Bladder | D2cm3 | ≤ 23.75 (27.5) Gy |
22.4 ± 2.0 [20.2,27.0] |
22.6 ± 2.1 [20.6,27.3] |
21.6 ± 2.3 [17.9,26.2] | – |
| Rectum | D2cm3 | ≤ 17.0 (19.45) Gy |
13.9 ± 2.9 [11.2,19.6] |
13.2 ± 3.0 [10.3,18.7] |
12.7 ± 3.9 [8.0,21.6] | – |
| Sigmoid | D2cm3 | ≤ 19.5 (21.65) Gy |
2.6 ± 3.1 [0.5,10.4] |
2.8 ± 3.0 [0.5,9.9] |
2.5 ± 2.7 [0.4,8.1] | – |
| Bowel | D2cm3 | ≤ 17.0 (19.45) Gy |
9.1 ± 5.9 [1.2,17.6] |
9.7 ± 7.3 [1.0,18.4] |
9.6 ± 6.6 [2.7,18.0] | – |