J. Chim. Phys. Vol. 95, N°4 p. 708-717
Transfert d'énergie linéique et radiosensibilité cellulaireA. Courdi1, J.P. Pignol2, N. Iborra-Brassart1, J. Hérault1, G. Fares3, A. Hachem3 and P. Chauvel1
1 Centre Antoine-Lacassagne, 33 avenue de Valombrose, 06189 Nice cedex 2, France
2 Hôpital du Hasenrain, 87 avenue d'Altkirch, 68189 Mulhouse cedex, France
3 Faculté des Sciences, Parc Valrose, 06108 Nice cedex 2, France
The response of human tumour cell lines to in vitro irradiation by high LET particles depends on several factors. For charged particles, there is an increase in radio-sensitivity with LET up to LET values of about 200 KeV/m, then it decreases for higher values. In clinical practice, the increase in the average LET value with depth leads to a continuous increase in relative biological effectiveness (RBE). The probability of particle traversal through the nucleus producing lethal damage is almost 1 for particles with very high LET values such as 7 MeV Ar (LET = 1500 KeV/ m); it is only 0.02 for 400 MeV O ions (LET = 20 KeV/ m). RBE is inversely related with dose, this relation being more marked for cells with small values after photon irradiation according to the linear-quadratic formula. Particles that are less efficient than photons in terms of average cell death induce heavy individual cell damage, as shown by the yield of multiple micronuclei (MN). With regard to RBE and intrinsic radiosensitivity, recent data using both the clonogenic method and the MN assay indicate that the higher the radioresistance to photon irradiation, the higher the RBE.
Key words: radiosensibilité -- TEL élevé -- particules chargées -- neutrons -- EBR
© EDP Sciences 1998