RESUMO
Tumor and healthy tissue samples were irradiated by 24 MeV protons. The samples were exposed to doses from 0 to 50 Gy and subsequently examined by Raman spectroscopy. The analysis of the intensity of characteristic peaks as a function of radiation dose exhibits different trends for the two types of tissue.
Assuntos
Prótons , Pele/efeitos da radiação , Análise Espectral Raman , Animais , Relação Dose-Resposta à Radiação , SuínosRESUMO
PURPOSE: Since the number of cancer patients treated by proton irradiation has increased in the last few years, it seems appropriate to study dose-dependent effects of proton irradiation on mammalian tissues in more detail. MATERIALS AND METHODS: Tissue samples of normal skin of mouse and swine, of a human tumour model xenograph, and of normal skin and a skin tumour (basal cell carcinoma) of a human patient of about 1 mm thickness were irradiated by 24 MeV protons (uniform delivered doses of 1, 7 and 50 Gy: skin of mouse and a human tumour model xenograph, and 0.5, 5 and 50 Gy: swine and human skin). Raman spectra of non-irradiated and irradiated samples were recorded and analysed. RESULTS: Amide I, P=O and C-O bond vibrations and aromatics were sensitive to the proton irradiation dose. In the C-H stretching region, the irradiation-mediated change of Raman spectra was significant only in the case of the skin tumour. CONCLUSIONS: It has been shown that Raman spectroscopy is suited to assess the radiation damage done to biological samples by protons. Proteins of the human skin tumour seem to be more sensitive to proton irradiation than proteins of normal human skin.
Assuntos
Prótons , Pele/efeitos da radiação , Análise Espectral Raman , Animais , Feminino , Humanos , Camundongos , Transplante de Neoplasias , Suínos , Transplante HeterólogoRESUMO
Various methods of dosimetry for protons with energies up to 25 MeV were compared for radiation fields as might be used in the skin treatment of patients or in biological experiments. The methods used were: Fluence of individually registered protons; Charge deposition in commercially available ionisation chambers; Thermoluminescence detectors, exposed in Munich and evaluated in Krakow; Photometricallly evaluated commercial Fricke dosimeter. An overall agreement within 5% was found between the absolute dose measurements. Depth-dose distributions for Bragg curves measured by a Markus chamber with a depth resolution of 10 micrometers agreed with calculations.
Assuntos
Prótons , Monitoramento de Radiação/métodos , Compostos Ferrosos , Aceleradores de Partículas , Doses de Radiação , Radiometria , Dosimetria TermoluminescenteRESUMO
Spin-transfer observables for p p-->Lambda Lambda have been measured using a transversely polarized frozen-spin target and a beam momentum of 1.637 GeV/c. Current models of the reaction near threshold are in good agreement with existing measurements performed with unpolarized particles in the initial state but produce conflicting predictions for the spin-transfer observables Dnn and Knn (the normal-to-normal depolarization and polarization transfer), which are measurable only with polarized target or beam. Measurements of Dnn and Knn presented here are found to be in disagreement with predictions from these models.