CPB Ljubljana 2018 course book

RECOMMENDATIONS FOR DOSIMETRY

• No margin is required, CTV= PTV. • The prescription dose is the minimum dose received by the CTV or a CTV surrogate (D90 > 100%, V100 > 90%) • Keep the hyperdose sleeves (200% isodose volumes) as thin as possible and not confluent • DNR (V100 / V150 ) ≤ 0.36; in intensity modulated BT <0.42 • In small GTVs (few cm3 and applicator spacing <10 mm) the DNR may be 0.50–0.52. • Dose through the skin should be avoided if possible • keep the dose in bone, nerves, vessels as low as possible (< prescription dose) • Use lead sheets or plastic spacers