MRI-Based Radiotherapy Planning to Reduce Rectal Dose in Excess of Tolerance
Table 2
Bladder volume exposed to high dose radiation.
CT
MRI
value
Rx to prostate only
Median cc (IQR)
V70
12.7 (10.8, 15.0)
9.6 (8.2, 12.9)
3.0 (−0.8, 4.7)
0.006
V75
10.2 (9.0, 12.2)
7.8 (6.6, 10.4)
2.3 (−0.9, 3.7)
0.008
V80
7.4 (6.4, 8.8)
5.6 (4.5, 7.2)
1.4 (−0.7, 3.2)
0.011
Rx to prostate+1 cm SVs
Median cc (IQR)
V70
16.5 (14.8, 17.7)
10.6 (9.4, 13.7)
5.1 (2.9, 6.8)
<0.001
V75
13.2 (11.9, 14.5)
8.7 (7.6, 11.2)
4.0 (2.2, 5.9)
<0.001
V80
9.1 (8.4, 10.9)
6.5 (5.6, 8.1)
2.7 (1.3, 4.4)
<0.001
V70, volume of organ that receives 70 Gy or higher; V75, volume of organ that receives 75 Gy or higher; V80, volume of organ that receives 80 Gy or higher; IQR, interquartile range; cc, cubic centimeters.
