Degradation of target coverage due to inter-fraction motion during intensity-modulated proton therapy of prostate and elective targets

Figures & data

Figure 1. Relative change in volume compared to the planning CT across the repeat CT scans for the rectum and bladder. The data points of the four patients selected for this study are shown with solid symbols, the other with crosses.

Figure 2. Sagittal view of IMPT dose distributions for SIB (left) and SEQ (right) delivery techniques for patient 3. The segmented contours of CTV-p (red), CTV-ln (pink) and the PTVs (blue) are displayed and overlaid with a dose colorwash. The colorwash ranges from 95% of the prescribed dose to PTV-ln/sv (blue) to 95% of the prescribed dose to PTV-p (orange).

Figure 3. The planned and simulated gEUDs for each patient for the SIB plans. Planned doses are denoted by black circles, bony anatomy-based set-up are in blue and fiducial-based set-up are in green markers.

Table I. Patient average difference (and range) in delivered versus planned D99.

		Fiducials [GyE]			Bony anatomy [GyE]
		4 mm	7 mm	10 mm	4 mm	7 mm	10 mm
SIB	CTV-p	−0.6 (−0.3 to −1.0)	−0.3 (0.0 to −1.0)	−0.5 (0.2 to −1.5)	−2.5 (−0.4 to −8.1)	−1.1 (−0.2 to −3.9)	−1.0 (0.0 to −3.6)
	CTV-sv	−9.1 (1.6 to −35.1)	−8.0 (1.8 to −31.8)	−7.0 (3.9 to −31.1)	−11.9 (1.0 to −39.2)	−9.4 (1.7 to −36.4)	−8.1 (4.2 to −35.9)
	CTV-ln	−3.1 (−0.4 to −8.1)	−2.9 (−0.2 to −7.6)	−3.2 (−0.1 to −9.1)	−2.0 (−0.2 to −5.9)	−2.3 (−0.1 to −7.0)	−2.5 (−0.2 to −7.8)