Table 2.

Comparison between conventional 3D dose calculation and path‐integrated 4D cumulative dose calculation in target volumes; dose in Gy. HI is dimensionless and 3D refers to the dose for $3{\mathrm{D}}_{\text{REF}}$.

Lesion	Target (volume in ${\mathit{\text{cm}}}^3$)	$D_{\mathit{\text{mean}}}$ (3D / 4D)	${\mathit{\text{BED}}}_{\mathit{\text{mean}}}$ (3D / 4D)	$D_2$ (3D / 4D)	$D_{98}$ (3D / 4D)	HI (3D / 4D)	${\mathit{\text{HI}}}_{3D}/{\mathit{\text{HI}}}_{4D}$ ($={\mathit{\text{HI}}}_{3D/4D}\%$)
A	GTV (22.7)	45.3 / 44.9	79.5 / 78.5	46.8 / 46.7	43.1 / 42.7	1.08 / 1.09	99.1
	ITV (31.1)	45.1 / 44.7	79.0 / 78.0	46.7 / 46.7	42.6 / 38.9	1.10 / 1.20	91.7
	PTV (66.4)	44.0 / 43.4	76.3 / 74.8	46.7 / 46.7	36.8 / 30.9	1.27 / 1.51	84.1
B	GTV (12.4)	42.7 / 40.4	73.1 / 67.6	43.4 / 43.2	41.1 / 39.8	1.06 / 1.08	98.2
	ITV (17.9)	42.1 / 39.0	71.6 / 64.4	43.3 / 43.2	36.9 / 33.8	1.17 / 1.28	91.4
	PTV (39.3)	41.1 / 37.8	69.2 / 61.7	43.3 / 43.2	31.7 / 26.4	1.37 / 1.64	83.5
C	GTV (54.5)	48.2 / 47.8	86.9 / 85.9	50.2 / 49.8	46.1 / 45.6	1.08 / 1.09	99.7
	ITV (87.0)	48.0 / 47.4	86.4 / 84.8	50.2 / 49.8	44.7 / 44.1	1.12 / 1.13	99.1
	PTV (168.7)	47.4 / 46.3	84.8 / 82.0	50.1 / 49.8	42.8 / 36.6	1.17 / 1.36	86.0
D	GTV (6.68)	55.3 / 55.0	116.5 / 115.5	55.8 / 55.6	54.3 / 53.9	1.02 / 1.03	99.6
	ITV (21.28)	54.8 / 54.4	114.9 / 113.6	55.7 / 55.5	53.0 / 52.2	1.05 / 1.06	98.8
	PTV (71.36)	52.7 / 50.7	108.2 / 102.1	55.6 / 55.4	46.3 / 35.3	1.20 / 1.57	76.5
E	GTV (86.16)	46.2 / 45.0	81.8 / 78.8	46.7 / 45.9	43.8 / 41.9	1.07 / 1.08	99.1
	ITV (100.5)	46.0 / 44.8	81.3 / 78.3	46.6 / 45.8	43.2 / 41.2	1.08 / 1.11	97.0
	PTV (187.24)	44.3 / 42.4	77.0 / 72.4	46.3 / 45.4	38.2 / 31.0	1.21 / 1.46	82.8

3D = three‐dimensional dose calculation; 4D = four‐dimensional dose calculation; $D_{\text{mean}}=\text{mean dose}$; ${\text{BED}}_{\text{mean}}=\text{biologically effective mean dose}$; $D_2=2\%\text{near}–\text{maximum dose}$; $D_{98}=98\%\text{near}–\text{minimum dose}$; HI = homogeneity index (the ratio of $D_2$ to $D_{98},D_2/D_{98}$); ${\text{HI}}_{3\mathrm{D}/4\mathrm{D}}\%$ = the percentage ratio of HI for 3D to 4D (${\text{HI}}_{3\mathrm{D}}/{\text{HI}}_{4\mathrm{D}}$). All doses in Gy.