A treatment planning study of the potential of geometrical tracking for intensity modulated proton therapy of lung cancer

Figures & data

Figure 1. IMPT plans on targets 1–9 studied in this work on the midventilation phase of a 4DCT study. The doses 10 to 110% of the prescription is displayed in dose colour-wash.

Figure 2. GTV V95% (left) and GTV average dose (right) as a function of Cranio-Caudal (CC) tumour peak-to-peak displacement for static beam and tracking.

Figure 3. An example of cumulative dose volume histograms for the GTV in each phase of the 4DCT for Target 4 for Tracking (left) and Static beam (right), respectively.

Table I. Patient and planning data for targets 1–9 studied in the present work; Left-Right (LR), Anterior-Posterior (AP) and Cranio-Caudal (CC) peak-to-peak displacement in cm, PTV and GTV V95%, as well as the volume in cm³ of the PTV and the GTV.

Target #	1		2		3		4		5		6		7		8		9
Tracking	No	Yes	No	Yes	No	Yes	No	Yes	No	Yes	No	Yes	No	Yes	No	Yes	No	Yes
PTV V95 (%)	41	92	100	97	99	100	97	98	98	99	72	99	100	98	80	95	95	94
GTV V95 (%)	51	97	100	100	100	100	98	100	97	98	99	100	100	99	82	98	95	100
PTV average dose (%)	90	99	100	100	101	101	99	99	100	100	98	99	100	100	98	100	100	100
GTV average dose (%)	92	100	100	101	101	101	99	100	100	100	98	100	100	100	98	100	100	101
LR (cm)	0.3	0.3	0.1	0.1	0.3	0.3	0.3	0.3	0.1	0.1	0.1	0.1	0.2	0.2	0.2	0.2	0.1	0.1
AP (cm)	0.4	0.4	0.2	0.2	0.8	0.8	0.4	0.4	0.1	0.1	0.4	0.4	0.2	0.2	0.1	0.1	0.3	0.3
CC (cm)	2.4	2.4	0.3	0.3	0.4	0.4	0.5	0.5	0.3	0.3	0.7	0.7	0.5	0.5	1.6	1.6	1.0	1.0
PTV (cm^3)	109	109	147	147	15	15	61	61	38	38	7	7	41	41	93	93	23	23
GTV (cm^3)	45	45	46	46	3	3	19	19	9	9	0.4	0.4	13	13	30	30	2	2

Figure 4. Example of sagittal plane through target (number 8) with the dose distribution overlaid for tracked beam (left) and static beam (right), respectively. A maximum of 122% of the prescription dose can be observed in the lung tissue for the static beam (right).