Table 7.

Dose constraints

Organ at risk	Ideal dose constraint (cGy) (EQD23)	Maximum* dose constraint (cGy) (EQD23)	ICRU point (cGy) (EQD23)	References
Rectum	<6500 D2cc	<7500 D2cc	<7500 point dose	58,65,78,80,81
Bladder	<8000 D2cc	<9000 D2cc	<9000 point dose	78,80−82
Vagina (recto-vaginal point)†	<6500 point dose	<7500 point dose	–	59,60
Sigmoid‡	<7000 D2cc	<7500 D2cc	–	83
Bowel‡	<7000 D2cc	<7500 D2cc†	–	83,84

Abbreviations: ICRU = International Commission of Radiation Units and Measurements; EQD2₃ = dose calculation to an equivalent dose of 2 Gy with an α-to-β ratio of 3. D2cc is the minimal dose to the 2 cm³ (2 mL) of the organ at risk receiving the maximal dose.

^*There will be occasions when exceeding these maximum constraints is necessary to adequately treat the targets of therapy, according to the clinical judgment of the treating physician.

^†The rectovaginal point is defined 5 mm posterior to the vaginal mucosa from the center of the vaginal sources.

^‡Dose constraints for sigmoid and bowel are based largely on expert opinion because there is minimal evidence of a dose response.