Table 4.

Evaluation of normal lung ${\mathrm{V}}_{20}$ in SBRT lung plans calculated by iPlan XVMC algorithm. First 5 patients had dose delivery schema of total 54 Gy in 3 fractions, and remaining 15 patients with 50 Gy in 5 fractions.

Patient No.	PTV Vol. (cc)	RTOG 0915 Minor Deviation	${\mathrm{V}}_{20}$ (%) a XVMC
1	11.1	10‐15	3.6
2	20.1	10‐15	2.2
3	27.1	10‐15	4.2
4	50.9	10‐15	10.0
5	68.1	10‐15	9.9
6	12.9	10‐15	1.5
7	15.0	10‐15	1.8
8	20.1	10‐15	2.1
9	21.0	10‐15	1.6
10	26.3	10‐15	3.1
11	31.2	10‐15	3.3
12	36.2	10‐15	2.3
13	37.1	10‐15	3.3
14	39.7	10‐15	9.2
15	39.8	10‐15	1.1
16	53.4	10‐15	4.7
17	56.5	10‐15	7.4
18	61.5	10‐15	5.7
19	132.0	10‐15	4.3
20	163.0	10‐15	12.8 b
AVG	46.1		4.7
STDEV	38.7		3.4

^aNormal lung ${\mathrm{V}}_{20}$ values ranged from 1.1% to 12.8% ($\text{mean}=4.7\%\pm 3.4\%$).

^bData that have minor deviations from RTOG 0915 criteria. No minor deviation in normal lung ${\mathrm{V}}_{20}$ from the RTOG 0915 criteria was observed; except for one patient (Patient #20), whose PTV was about 163 cc (the largest PTV recommended by RTOG protocol), had ${\mathrm{V}}_{20}=12.8\%$.

PTV = planning target volume; V20 = percentage of total normal lung minus ITV receiving dose equals larger 20 Gy or more; AVG = average; STDEV = standard deviation.