Variations in Rectal Volumes and Dosimetry Values Including NTCP due to Interfractional Variability When Administering 2D-Based IG-IMRT for Prostate Cancer

Table 2

Rectal interfraction volume changes.

Patient number	Volume (cc)
	Initial plan	CBCTs
		Median (range)
1	41.8	47.5 (35.0–82.7)
2	82.0	74.4 (60.1–99.9)
3	43.1	53.7 (38.9–77.0)
4	38.7	40.8 (36.3–89.2)
5	31.3	32.3 (25.8–36.9)
6	43.2	42.2 (39.0–108.3)
7	39.8	36.9 (30.8–89.7)
8	54.3	52.6 (45.5–82.2)
9	65.8	56.0 (51.9–83.4)
10	50.6	42.5 (35.6–77.7)
11	69.3	62.9 (48.9–96.3)
12	62.3	53.7 (43.6–83.8)
13	50.4	48.4 (43.8–70.3)
14	47.3	39.6 (32.4–41.7)
15	33.1	34.7 (29.1–46.3)
16	45.7	32.5 (30.7–55.8)
17	42.4	44.7 (40.0–46.6)
18	45.6	40.1 (37.3–48.8)
19	51.2	49.9 (40.2–92.9)
20	36.8	44.7 (38.1–60.5)