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respectively. The radon concentration for location 10 in Ono-Ara local government exceeded the recommended limit. However, the overall average indoor radon concentration of the three local governments was found to be lower than the world average value of 40 Bqm -3. Hence, there is need for proper awareness about the danger of radon accumulation in dwelling places.

Objective: This study aimed to evaluate the dosimetric properties of treatment plans obtained from three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy techniques (IMRT) plans for left chest wall breast cancer patients. Materials and Methods:A total of 20 patients with left-sided chest wall radiotherapy were randomly selected with the dose prescriptions: 42 Gy and 45 Gy in 15 and 18 fractions, respectively. Treatment plans were obtained using 3D-CRT and IMRT for each patient. Five to seven beams were used for IMRT, while tangential beams were used for 3D-CRT. Planning target volume, D near-max (D 2 ), D near-min (D 98 ), D mean , Homogeneity and Conformity Indices (HI and CI) were obtained. Similarly, mean doses to organs at risk (OAR), V 5 , V 10 , V 20 , V 25 were generated from the dose-volume histogram and compared.Results: IMRT showed a significant improvement in HI compared to 3D-CRT (p<0.0001). Although there was no significant difference in sparing of the left lung between both plans for high-dose volumes (V20: 18.2 vs 30.55, p<0.0001), (V25: 11.17 vs 28.12, p<0.0001). IMRT however showed supremacy to 3D-CRT with high-dose volumes for the heart, including V20 (4.44 vs 10.29, p = 0.02), V25 (2.08 vs 8.94, p = 0.002). 3D-CRT was better than IMRT in low-dose volumes for left lung (V5: 92.23 vs 56.60, p<0.001; V10: 60.98 vs 47.20, p = 0.04) and heart (V5: 57.45 vs 30.39, p = 0.004). Conclusion:IMRT showed better homogeneity and sparing of high-dose volumes to OAR than 3D-CRT. On the other hand, 3D-CRT showed a reduction of low-dose volumes to OARs than IMRT.

Background The use of X-ray as a diagnostic tool for complication and anomaly in the neonatal patient has been helpful, but the effect of radiation on newborn stands to increase their cancer risk. This study aims to determine the mean, 50th percentile (quartile 2 (Q2)), and 75th percentile (quartile 3 (Q3)) entrance surface dose (ESD) from anteroposterior (AP) chest X-ray and to compare our findings with other relevant studies. The study used calibrated thermoluminescent dosimeters (TLDs), which was positioned on the central axis of the patient. The encapsulated TLD chips were held to the patients’ body using paper tape. The mean kilovoltage peak (kVp) and milliampere seconds (mAs) used was 56.63(52–60) and 5.7 (5–6.3). The mean background TLD counts were subtracted from the exposed TLD counts and a calibration factor was applied to determine ESD. Results The mean ESDs of the newborn between 1 and 7, 8 and 14, 15 and 21, and 22 and 28 days were 1.09 ± 0.43, 1.15 ± 0.50, 1.19 ± 0.45, and 1.32 ± 0.47 mGy respectively. A one-way ANOVA test shows that there were no differences in the mean doses for the 4 age groups (P = 0.597). The 50th percentile for the 4 age groups was 1.07, 1.26, 1.09, and 1.29 mGy respectively, and 75th percentile were 1.41, 1.55, 1.55, and 1.69 mGy respectively. The mean effective dose (ED) in this study was 0.74 mSv, and the estimated cancer risk was 20.7 × 10−6. Conclusion ESD was primarily affected by the film-focus distance (FFD) and the patient field size. The ESD at 75th percentile and ED in this study was higher compared to other national and international studies. The estimated cancer risk to a newborn was below the International Commission on Radiological Protection (ICRP) limit for fatal childhood cancer (2.8 × 10−2Sv−1).

Aim: This study aimed at calibrating a new set of GR-200A thermoluminescent dosimeters (TLDs) in low and medium kilovoltage energy photon therapy beams and in a diagnostic beam of known beam quality, in order to determine their response and to establish if the same set of TLDs could be used across both environments for in-vivo dosimetry purposes. Methods and Materials:A set of 20 TLDs was used for this study. An Oven type PCL 3 was used to anneal the TLDs. The response of the TLDs was read using the Reader type LTM manufactured by Harshaw Bicron, United State of America. Vacuum tweezers were used to transfer the TLDs at the time of measurements and calibration. TLDs were kept in a subdued ultra-violet environment between the annealing and irradiation process.TLDs were placed on a 30 x 30 x 17.6 cm³ Polymethylmethacrylate (PMMA) phantom during irradiation. A calibrated Orthovoltage machine was used to deliver a known absorbed dose to the TLDs. A cylindrical ionization chamber (PTW 30001) and an electrometer (PTW 10008) were used to confirm the absorbed dose delivery of the orthovoltage machine at the time of measurement. Likewise, a calibrated LX40 radiotherapy Simulator was used to deliver a known diagnostic absorbed dose to the TLDs. A TM77334 ionization chamber was used similarly to confirm the absorbed dose.The TLDs were also irradiated on the PMMA phantom. The accepted variation in raw response of the individual TLDs from the average of the batch was compared and a deviation of less than ± 20 % was considered within tolerance. A 10 % tolerance was subsequently considered suitable for the measurement of absorbed dose. 16 of the 17 TLDs were within ± 10 % dose tolerance at 95 kV p whereas all the TLDs that were within the accepted response level at the 180 kV p and 300 kV p , were within the iii ± 10 % dose tolerance. 12 of the 15 TLDs at the diagnostic beam energy were within the ± 10 % dose tolerance. Three of the TLDs were therefore rejected at all energies. Conclusion