Radioterapia stereotactică - principii şi aspecte practice

Stereotactic Radiation Therapy is a type of external beam radiation therapy that delivers high dose to a relatively small target volume in one or few fractions, a technique that requires extremely conformal dose distributions, so the highest dose being delivered centrally in the tumor volume with a rapid fall off of dose to spare the adjacent healthy tissue. The dose is prescribed to the tumor periphery, usually to the 80% isodose (60-90%), the aim being that 95% of the target volume (PTV) is conformally covered by the prescription isodose surface and 99% of the target volume (PTV) receives a minimum of 90% of the prescription. Stereotactic radiotherapy can be used as a primary therapy for early stage primitive cancer or metastatic tumors (cranial or extra-cranial tumors), for patients in a good health conditions, with minimum 6 months life expectancy, and relatively small tumors.