An analysis of planned versus delivered airway doses during stereotactic lung radiotherapy for central tumors

Figures & data

Figure 1. For all seven cases the difference between the proximal bronchial tree wall (PBT-Wall) dose based on the pretreatment CBCT and the planned fractional dose to the hottest 0.25, 0.5 and 1 cm³ of PBT-Wall is shown graphically.

Figure 2. This illustrates the limited difference between the planned and delivered (pretreatment CBCT) position of the center of mass of the D0.5 cm³ PBT-Wall structure. All individual displacements in each translational direction have been combined (n = 165 individual x, y and z measurements combined) and 85% of differences were within ±2.0 mm.

Table I. A summary of the differences between the estimated pretreatment dose and the planned dose for the “hottest” parts of the proximal bronchial tree wall (PBT-wall).

	(Gy)
	Case 1	Case 2	Case 3	Case 4	Case 5	Case 6	Case 7
0.25 cm^3 PBT-Wall
Planned dose/Fr	7.93	8.81	6.79	9.77	8.21	9.13	7.79
Δ Mean	−0.01	−0.02	−0.59	−0.05	−0.22	0.01	0.02
1SD	±0.05	±0.22	±0.19	±0.22	±0.28	±0.09	±0.04
Range	−0.06–0.06	−0.32–0.29	−0.84 to −0.36	−0.40–0.18	−0.52–0.21	−0.18–0.10	−0.03–0.08
0.50 cm^3 PBT-Wall
Planned dose/Fr	7.77	8.63	6.27	9.08	7.22	8.96	7.70
Δ Mean	−0.07	−0.17	−0.63	0.01	−0.30	0.00	0.03
1SD	±0.10	±0.40	±0.15	±0.30	±0.46	±0.08	±0.04
Range	−0.20–0.06	−1.06–0.27	−0.79 to −0.48	−0.37–0.36	−0.73–0.54	−0.15–0.10	−0.01–0.09
1.00 cm^3 PBT-Wall
Planned dose/Fr	6.50	8.26	5.36	8.24	5.11	8.66	7.45
Δ Mean	−0.19	−0.69	−0.52	−0.02	−0.16	0.00	−0.01
1SD	±0.30	±1.14	±0.13	±0.23	±0.36	±0.07	±0.08
Range	−0.51–0.23	−3.21–0.30	−0.69 to −0.39	−0.31–0.30	−0.55–0.54	−0.13–0.09	−0.10–0.14

Δ, delta; Fr, fraction; Gy, Gray; SD, standard deviation.