Background: The knowledge of distribution of radionuclides and background radiation levels in the environment is important for assessing the effects of radiation exposure due to both terrestrial and extra-terrestrial sources. Materials and Method: In-situ gamma dose survey and gamma spectrometry was employed to investigate background radiation levels in Ijebu-Ife. Results: In-situ gamma dose rates vary from 0. 02 to 0. 10 μ Sv/hr with mean value of 0. 05 μ Sv/hr which is less than 0. 133 μ Sv/hr, recommended by the ICRP. The resulting annual effective dose was below 1 mSv/yr maximum permissible limit for the general public set by the UNSCEAR, 2000. The activity concentrations of the three naturally occurring radionuclides in soils ranged from Below Detection Level (BDL) to 320. 11 ± 28. 53, 9. 11 ± 1. 65 and 8. 55 ± 0. 95 Bq/kg with mean values of 119. 05 ± 11. 24 Bq/kg, 4. 44 ± 1. 01 Bq/kg and 4. 55 ± 0. 62 Bq/kg respectively which are lower than the average values of 400, 35, and 30 Bq/kg recommended by the UNSCEAR, 2000 for 40K, 226Ra, and 232Th respectively. The mean computed values for absorbed dose rate, annual effective dose and radium equivalent are 10. 03 nGy/hr, 0. 03 mSv/yr, 20. 11 Bq/kg respectively, which fall within UNSCEAR, 2000 threshold. Conclusion: A significant positive relationship exists between the in-situ and evaluated effective dose equivalents (r = 0. 89, p < 0. 05). Radiation dose results indicate insignificant radiological risk, making the study area safe for living and agriculture purposes.

Background: Best dose distribution in target volume and control of Organ at Risk (OAR) dose are the two main goals in brachytherapy. Materials and Methods: In this study in vivo dosimetry in 4 rectal points was performed by Transillumination Dosimeter (TLD) s and the measured doses were compared in different patients. One point was reported to have the maximum dose in each patient and the very dose was considered as rectal dose according to ICRU-38 prescription; however, the next higher dose was also considered the same as the highest point when the difference was not more than 10% of the highest value. Results: In more than 50% of the cases the 1st and 2nd highest points were in the same range with less than 10% variation. There were 3 points in approximately equal dose in 7% of cases. Conclusion: These findings are challenging with the ICRU-38 recommendations reporting the existence of a sole maximum rectal dose. So it seems wise to consider an isodose plate of maximum doses instead of one point only.