Table 4 Treatment and dosimetric parameters reported in selected studies comparing VMAT and DCAT SIMT SRS techniques for multiple brain metastases

No of patients

36

10

20

20

30

No of lesions

367

40

66

97

217

Median number of lesions for patient

9 (2–25)

3 (2–6)

5 (2–10)

7.5 (4–10)

Median SRS (dose/fraction)

20 Gy, SF

20 Gy, SF

19 Gy, SF

18–27 Gy, 1–3 fr

14–24 Gy, SF

Median PTV (cm3)

0.32 (0.17–1.18)

3.15 (0.14–24.61)

0.8 (0.1–11.9)

2 (0.1–18.6)

0.35 (0.014–17.73)

Median total PTV (cm3)

3.42 (0.61–9.37)

10.6 (0.6–28.66)

NR

9.6 (0.5–29)

7.05 (0.49–27.32)

PTV Dmax/D2%

< 135% of PD

< 125% of PD

< 125% of PD

< 150% of PD

< 175% of PD

PTV Dmin/D98%

> 98%

> 99.5%

> 98%

> 98%

NR

Mean target coverage

VMAT 99.1% ± 2.4%

DCAT 98.9 ± 2.9%

NR

NR

VMAT 98.2% ± 2.9%

DCAT 96.4 ± 3.5%

VMAT 96.9% ± 2.5%

DCAT 97.5 ± 2.3%

Median conformity index

VMAT 0.6 (0.46–0.85)

DCAT 0.75 (0.52–0.86)

VMAT 0.67 ± 0.16*

DCAT 0.65 ± 0.08*

VMAT 0.73 (0.38–0.88)

DCAT 0.75 (0.58–0.89)

VMAT 0.94 (0.85–1.00)*

DCAT 0.75 (0.4–0.96)*

VMAT 0.77 ± 0.12

DCAT 0.7 ± 0.1

Median gradient index

VMAT 5.61 (3.64–8.37)

DCAT 4.54 (3.45–7.13)

VMAT 7.1 ± 3.1*

DCAT 3.9 ± 1.4*

VMAT 7.17 (3.35–33.0)

DCAT 5.99 (3.5–15.73)

VMAT 4.17 (3.32–7.46)*

DCAT 4.31 (3.29–5.79)*

NR

Median brain dose

VMAT 2.74 (0.55 -5.85)

DCAT 2.37 (0.65–5.62)

NR

NR

VMAT 2.99 (0.76 -6.17)*

DCAT 3.22 (0.85–7.34)*

VMAT 2.76

DCAT 2.57

Median total V12Gy

VMAT 18.51 (2.2–62.3)

DCAT 13.65 (1.87–45.9)

VMAT 46.3 ± 35.9*

DCAT 36.3 ± 27.1*

VMAT 3.1 (0.5–13.9)

DCAT 2.1 (0.1–13.1)

VMAT 23.7 (1.7–86.6)*

DCAT 37.3 (3.2–157.5)*

VMAT 19.2

DCAT 23.7