Decreasing the Dose to the Rectal Wall by Using a Rectal Retractor during Radiotherapy of Prostate Cancer: A Comparative Treatment Planning Study

Table 1

Evaluation criteria used for the optimisation, selected from QUANTEC [25]. Due to different PTV margins and the possibility to retract the rectal wall, the limits were lower in this study.

Priority	Structure	Present study; criteria	QUANTEC; criteria
1	PTV	𝐷98% ≥ 95%
2	Rectal wall	𝑉40.1Gy ≤ 0 cm^3	𝑉70Gy < 8 cm^3∗
2	Rectal wall	𝑉38.3Gy ≤ 1 cm^3	𝑉65Gy < 10 cm^3∗
2	Rectal wall	𝑉36.5Gy ≤ 1 cm^3	𝑉60Gy < 14 cm^3∗
2	Rectal wall	𝑉32.6Gy ≤ 1 cm^3	𝑉50Gy < 20 cm^3∗
3	Bladder	𝑉32.6Gy ≤ 50%

∗The volumes are expressed in relative volume in QUANTEC. It is translated to absolute dose for a rectal wall volume of 40 cm³.