Potential dosimetric benefits of adaptive tumor tracking over the internal target volume concept for stereotactic body radiation therapy of pancreatic cancer

Table 2 Comparison of the ITV and tracking concept

Dp [Gy]	Median 3D _ITV [Gy]	Median (prctiles) [Gy] 3D _Tracking−3D _ITV	p-value	Median 4D _ITV [Gy]	Median (prctiles) [Gy] 4D _Tracking−4D _ITV	p-value
	TV			GTV
D _mean	38.00	0.94 (0.39 to 1.09)	< 0.05	38.08	0.27 (–0.16 to 0.55)	0.233
D _max	41.55	0.01 (–0.13 to 0.04)	0.791	41.85	–0.27 (–0.98 to 0.14)	0.064
D _min	24.59	0.75 (–0.07 to 1.98)	< 0.05	24.83	0.34 (0.19 to 2.00)	0.064
D ₉₅	29.02	3.70 (1.19 to 5.51)	< 0.05	30.87	1.56 (0.65 to 2.43)	< 0.05
D ₂	40.87	0.05 (–0.11 to 0.20)	0.677	41.25	-0.27 (-0.81 to -0.04)	< 0.05
D ₉₈	26.20	3.45 (1.24 to 5.30)	< 0.05	27.78	1.73 (0.77 to 2.25)	< 0.05
Bowel
D _mean	4.42	–0.27 (–0.56 to –0.06)	0.092	5.01	–0.45 (–0.58 to –0.24)	< 0.05
D _0.1cc	26.87	–1.34 (-1.51 to –0.73)	< 0.05	26.20	–0.60 (–1.14 to 1.11)	0.791
Duodenum
D _mean	9.95	–1.13 (–1.53 to –0.93)	< 0.05	10.45	–1.30 (–1.59 to 0.62)	< 0.05
D _0.1cc	27.31	–0.43 (–0.82 to –0.03)	0.164	27.97	0.46 (–1.41 to 0.63)	0.910
Stomach
D _mean	3.34	–0.39 (–0.80 to –0.08)	< 0.05	3.38	–0.30 (–0.60 to –0.07)	< 0.05
D _0.1cc	23.57	–1.04 (–2.17 to –0.03)	< 0.05	22.62	–0.11 (–1.11 to 0.97)	0.791
Liver
D _mean	2.04	–0.17 (–0.37 to -0.12)	< 0.05	2.15	–0.18 (–0.35 to -0.07)	< 0.05
Left Kidney
D _mean	3.89	–0.21 (–0.60 to 0.18)	0.266	3.58	–0.29 (–0.60 to -0.15)	< 0.05
Right Kidney
D _mean	3.90	–0.24 (–0.46 to 0.16)	0.176	4.00	–0.40 (–0.57 to 0.12)	< 0.05
Spinal Cord
D _max	9.24	–0.31 (–1.10 to 0.47)	0.569	9.26	–0.37 (–1.55 to 0.56)	0.569

Dp: Dose parameter, prctiles = (25-percentile, 75-percentile), Target volume (TV): (ITV concept); GTV (tumor tracking).
Differences of the dose parameters for tumor volume and organs at risk after 3D and 4D dose calculation are given

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