The Radiobiology of Targeted Radiotherapy

摘要: Targeted radiotherapy consists of biologically selective irradiation malignant cells by means radionuclides attached to tumour-seeking molecules. A variety clinical strategies for targeted may be used, which different normal tissues will critical. large number exist, emitting nuclear particles with a range path lengths from nanometres millimetres. An important feature normal-tissue radiobiology is the dose-rate effect, especially marked late-responding tissues. Radiobiological calculations imply that tolerance dose using low-LET emitters depend strongly on effective half-life radionuclide, affected pharmacokinetics and vary between patients. Some designed improve therapeutic radio (e.g. accelerated clearance radionuclide) have modulating effects dose. Tumour response governed 'four Rs' (repair, repopulation, reoxygenation, redistribution) as well mechanisms peculiar radiotherapy. Analysis based extended linear quadratic model predicts major importance only minority tumours. Most radiation tumour usually delivered over time-scale few days. This might give insufficient time making use hypoxic sensitizers appropriate. special complex relationship curability size radionuclides. For long-range beta-emitters, microscopic tumours operationally resistant because inefficient absorption radionuclide disintegration energy in small volumes. Short-range more efficient sterilization micrometastases but larger require an unattainable degree homogeneity distribution. Optimal it combined external-beam or chemotherapy. Experimental studies necessary investigate those features differ irradiation. Future directions include minimal numbers detected molecular probes. Such applications call short-range alpha-emitters Auger whose become increasingly important.