ABSTRACT
Background: Computed tomography (CT) is an axial imaging modality that uses X-ray. The study is to determine the amount of X-radiation that reaches the thyroid glands during brain CT.Methods: A prospective study was carried out in Rivers State University Teaching Hospital’s Radiology Department with 60 participants sent for brain CT scan. A 64 slice helical GE Optima CT machine was used while radiation dose reaching the thyroid gland was measured with themoluminiscent dosimeter (TLD) chips (TLD LiF-100). The TLD chip was placed on the anterior aspects of the neck at the level of 6th cervical vertebra (C6) and held in place with adhesive tapes. The TLD chip was later sent to the radiation dosimetric laboratory for reading. Collected data was analyzed using SPSS windows version 22.0 statistical software. A descriptive statistical tool was used to determine central tendencies. Pearson correlation and linear regression analysis models were also used to evaluate correlation between variables.Results: The mean (±SD) CTDI, DLP and brain Effective Dose were 37.265±13.098mGy, 662.451±230.782mGy-cm and 1.667±0.603mSv respectively. The Scatter X-Radiation reaching the thyroid gland and resultant Effective Dose were 5.26±3.13mSv and 0.26±0.16mSv respectively. A positive correlation between brain and thyroid gland effective doses yielded a Pearson’s correlation coefficient (r) of 0.892 within a confidence interval of 0.01 (p value of 0.01) showing significant correlation.Conclusions: The amount of radiation received by the thyroid gland during brain computed tomography scan is significant. Therefore, it is pertinent to protect the thyroid gland during the procedure.
ABSTRACT
Aim: To assess the radiation dose received in a clinical/real life setting by patients visiting selected radiological centres in Enugu, Enugu State, southeast of Nigeria for diagnostic computed tomography (CT) scans of the heads and thus assess compliance to the diagnostic reference levels (DRL). Study Design: A prospective cross-sectional survey design. Place and Duration of Study: CT Units of University of Nigeria Teaching Hospital, Memfys Hospital for Neurosurgery and Conquest Medical Imaging Limited in Enugu, Enugu State, Nigeria between April 2012 and January 2013. Materials and Method: Radiation doses absorbed by 98 patients (60 males and 38 females, age range 3-65years) that presented for CT scans of the head at the study centres were prospectively measured using lithium fluoride thermoluminescent dosimeter, LiF-TLD (TLD-100) chips. The mean absorbed dose, mean effective dose, collective dose and the per caput dose with their standard deviations were obtained. Results: The mean absorbed dose was 4.315 ± 3.815mSv (range 1.005-17.607mSv) and the mean effective dose was 2.244±1.984 mSv. In children (0-15years) the mean absorbed dose was 5.604±4.904mSv and mean effective dose, 2.914±2.278 mSv and these doses were higher than that of the adults. The annual collective dose was 224.40±198.4 person-mSv and the annual per caput dose was 5.9 x 10-7mSv. The calculated mean organ effective doses were 0.147±0.056mSv, 0.884±0.334mSv, 0.147±0.056mSv, 0.3540±0.134mSv and 0.147±0.056mSv for the brain, eye lenses, thyroid gland, red bone marrow and breast respectively. Conclusion: TLD chip were used to assess patients’ radiation dose in a clinical setting. The overall mean effective dose (2.244mSv) was in compliance with the recommended DRL. The radiation dose received correlated positively with the tube current (mA) and number of images obtained but negatively with the scan time, patients’ head AP dimension and age. Radiation risks from CT can be reduced through justification of the procedure and dose optimization.
ABSTRACT
This study was conducted to establish the normal values of ovarian volumes in this locality. A convenience sample of 141 apparently and gynecologically healthy and non pregnant females was studied using transabdominal sonography. The length; width and anteroposterior dimensions of both the right and left ovaries were measured. Volumes of the ovaries were determined using the prolate ellipsoid formula. The mean ovarian volumes were found to be a 9.5cm3 and 10.cm3 for the right and left ovaries respectively. A mean ovarian volume (Right and left) was 9.9cm3. A mean (right and left) range of 5.3cm3 to 13.9cm3 was also established. Significant correlations were noted between ovarian volumes and age (r=0.93; p0.05) and between ovarian volumes and body weight (r