Evaluation of OAR dose sparing and plan robustness of beam-specific PTV in lung cancer IMRT treatment

Radiation Oncology

Table 4 Summary of dose to targets and OARs for all patients, shown as mean (standard deviation)

Parameter	General PTV optimization plan	BSPTV optimization plan	P^a
CTV, D_98% (Gy)	61.68 (0.99)	61.40 (1.15)	0.280
General PTV, D_98% (Gy)	60.00 (0.00)	58.84 (1.01)	0.001^f
General PTV, D_2% (Gy)	63.38 (1.35)	63.36 (1.53)	0.649
General PTV, CI	0.85 (0.05)	0.86 (0.05)	0.233
General PTV, HI	0.05 (0.02)	0.07 (0.03)	0.002^f
BSPTV, D_98% (Gy)	60.53 (0.50)	60.00 (0.00)	0.003^f, 0.003^c,f, 0.001^d,f
BSPTV, D_2% (Gy)	63.48 (1.41)	63.36 (1.51)	0.975
BSPTV, CI	0.79 (0.07)	0.84 (0.05)	0.003^f, 0.281^e
BSPTV, HI	0.05 (0.02)	0.05 (0.02)	0.100
Ring PTV, D_mean (Gy)	40.27 (6.83)	38.89 (7.13)	0.001^f
Ring BSPTV, D_mean (Gy)	40.68 (6.72)	39.43 (7.08)	0.001^f
Ring PTV, volume (cm³)	195.61 (203.99)		0.001^b,f
Ring BSPTV, volume (cm³)	201.21 (210.89)
Affected lung, V20	16.69 (11.32)	16.20 (10.85)	0.005^f
Contralateral lung, V20	0.36 (0.01)	0.36 (0.01)	1.000
Total lungs, V20	7.25 (6.40)	7.02 (6.00)	0.008^f
Affected lung, V5	29.22 (14.87)	28.75 (14.43)	0.013^f
Contralateral lung, V5	6.91 (11.71)	6.71 (11.56)	0.028^f
Total lungs, V5	16.26 (12.72)	15.92 (12.37)	0.015^f
Affected lung, D_mean (Gy)	9.18 (5.51)	8.93 (5.28)	0.005^f
Contralateral lung, D_mean (Gy)	0.97 (1.43)	0.95 (1.42)	0.012^f
Total lungs, D_mean (Gy)	4.79 (3.33)	4.67 (3.18)	0.003^f
Spinal cord, D_1% (Gy)	16.14 (16.50)	15.72 (15.89)	0.009^f

HI homogeneity index, CI conformity index
^aComparison of general PTV optimization plan with BSPTV optimization plan
^bComparison of volumes of ring PTV and ring BSPTV
^cComparison of D_98% of general PTV and BSPTV in the same general PTV optimization plan
^dComparison of D_98% of general PTV and BSPTV in the same BSPTV optimization plan
^eComparison of CI of general PTV in the general PTV optimization plan and CI of BSPTV in the BSPTV optimization plan
^fP < 0.05

ISSN: 1748-717X