Physics Bucharest 2017

Normal Tissue Tolerance • The maximum radiation dose or intensity of fractionated radiotherapy that is deemed to produce an acceptable level of normal tissue toxicity.

• Often specified as the dose that can be delivered with a risk of damage no higher than 5% at 5 years (TD5/5) or the dose that can be delivered with a risk no higher than 50% at 5 yrs (TD50/5). • Emami (1991) reviewed the tolerances for partial and whole organ irradiation. • Q uantitative E stimates of N ormal T issue E ffects in C linic : Joint AAPM-ASTRO initiative published • Int J Rad Oncol Biol Physics 76 No.3 supplement 2010