GAMMA-RAYS DETECTION OF RADIONUCLIDES IN HUMAN TISSUES

This study is carried out to detect and measure the specific activities of radionuclides in cancerous samples of human tissues that excised from Baghdad city patients. The measurements were done using spectral analysis  technique for gamma-ray with 2"×2" NaI(Tl) scintillation detector.Our present investigations are based on the study of 24 abnormal samples and 8 normal samples for comparing the results. These samples include four types of fresh tissues (kidney, colon, breast, and uterus) that may be obtained with great mass. These samples had been collected from the histopathology department for education laboratories in Madenat Al-Ttib and specialized surgical hospital.Each sample is taken with 250g in weight, washed with distilled water to remove the formalin liquid (conservator substance), cut, put in the Marenilli Beaker uniformly and then examined with NaI(Tl) detector for a period of 4 hours (14400s) and 530 V as an operating voltage.Detector efficiency was measured by using Eu-152 source while gamma-ray spectra for tissues samples had been calibrated with respect to spectra of Cs-137, Co-60 and Na-22 sources.Six radionuclides have been detected in the selected samples where distributed between (2-5) radionuclides in each sample. These radionuclides included: two radionuclides (Bi-214 and Pb-214) belonging to the uranium series; two radionuclides (Ac-228 and Tl-208) belonging to the thorium series; one  artificial radionuclide (Cs-137); and  the  natural  radionuclide (K-40).The specific activity of detected U-238 (U-238 decay products) ranged between (1.02-7.46 Bq/kg) in the abnormal samples and (0.88-2.01 Bq/kg) in the normal samples while the specific activity of detected Th-232 (Th-232 decay products) ranged between (0.59-4.84 Bq/kg) in the abnormal samples and (0.49-2.71 Bq/kg) in the normal samples.The artificial radionuclide (Cs-137) is detected in all samples with specific activity ranged between (0.64-6.46 Bq/kg) in the abnormal samples and (0.5-3.46 Bq/kg) in the normal samples. The natural radionuclide (K-40) is detected in all samples too, but with largest specific activity compared with other radionuclides where it ranged between (44.18-85.36 Bq/kg) in the abnormal samples and (40.62-56.95 Bq/kg) in the normal samples.The results indicate that same radionuclides are often appeared in both normal and abnormal samples for the same type of tissue but with least specific activities in the normal samples.