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BACKGROUND፡ The thyroid, along with the breast, lung, and bone marrow, is among the most radiosensitive organs. This study aims to assess the rate of unnecessary radiation exposure to the thyroid gland in patients who had chest Computed Tomography (CT) at a large teaching hospital. METHOD: Hospital-based retrospective cross-sectional study on 1,306 patients who underwent chest CT from July 2018 to January 2019. Thyroid gland inclusion along with the CT dose of the studies was evaluated. Data was collected by evaluating chest CT scans from Picture Archive and Communication System (MedWeb). RESULT: Out of 1306 patients, who had Chest CT scans intravenous iodinated contrast media was used in 95.4% of the CT scans. The thyroid was included in 99.8% of the scans, out of which 76.9% included the whole thyroid gland. Among the patients who had previous CT scans, 75.3% had one previous scan and 24.7% had two previous scans. DLP (Dose Length Product) in mGycm was lower in females (360.33±32) compared to males (426.45±378.4). The lowest DLP value was observed in the pediatric patients in the age range of 1-5 years which was 146.83, while the highest was observed among those above 18 years of age with mean DLP of 418.31. CONCLUSION: The majority of chest CT scans unnecessarily include the whole thyroid gland, which is one of the most sensitive organs for radiation-induced effects. Authors recommend optimized technique for chest scans to avoid future impacts.

Additional file 1. Appendix A. Survey Questionnaire.

Background The clinical value of computed tomography imaging for the diagnosis of pediatric disease is unquestionable. However, Inappropriate or unskilled use may result in unnecessary exposures. Hence, a computed tomography involving the exposure of a patient to ionizing radiation must be both justified and optimized. Objective The primary goal of this research was to evaluate the revalue of applying justification to Computed Tomography requests in avoiding unnecessary radiation exposure in pediatric patients. Methods Institution-based cross-sectional study was conducted at three government hospitals from March 2018 to July 2018 G.C. All pediatric patients who were ≤ 15 years years of age with available CT request forms were evaluated for justification of radiation doses. Data were recorded by using structured format. The collected data were checked for completeness, edited, coded, and entered into Social Science (SPSS) version 25 software for data analysis. Results out of 381 pediatric patients sent for computed Tomography imaging. Seventeen (17) request forms had more than one anatomical region. Therefore, a total of 398 distinct anatomical CT requests were received. Of these, 225 (59.1%) were males and 156(40.9%) were females. A review of previous studies was sufficient to provide needed information in 23 (6%) cases. In 21 (5.5%) patients magnetic resonance imaging was recommended instead of computed Tomography. 20.7% of pediatric patients (79 out of 381 patients) were protected from unnecessary radiation exposure by using principle of justification Conclusions Our research demonstrates that a significant amount of unnecessary radiation exposure can be reduced from paediatric patients using principle of justification

Objectives The aim of this research was to develop an appropriate algorithm-routine that can automatically detect and classify liver cancers from the digital images of CT sample based on the texture and morphological features. Method The digital image processing (DIP) provides techniques first for liver image segmentation using semi-automatic technique from the enhanced abdominal CT images and classification using Artificial Neural Network (ANN) through texture features, then the liver tumor automatically extracted from the liver image using Otsu method which is a histogram based thresholding and the classification using ANN through morphological features. Result The samples were collected from a number of thirty six diagnosed patients in the procedure of abdominal CT images, at axial view in Black Lion Hospital from DICOM store in Addis Ababa. These images were selected to be processed and analyzed to get best generated result of the predefined classification model based on the extracted features. First nine texture features differentiate 12 normal and 24 abnormal liver images out of the given sample’s containing 36 images then tumor images extracted from the 24 abnormal images, the ANN classifier using six morphological features classified the 24 abnormal liver images as benign and malignant. It’s result presented by confusion matrix and showed that the maximum accuracy rate for tumor classification was 95.8%. The performance can be increased more by increasing the number of samples. Conclusions The outcome of this research work help radiologists to follow the condition of diseases at early stages and classify tumor as benign and malignant. It also helps in decreasing the rate of presence of disease by detecting cancer in its earlier stages.

BACKGROUND: Computed Tomography plays a priceless role for diagnostic and therapeutic purpose; however, applying an optimized Computed Tomography Technique to produce qualified image while delivering minimum radiation dose to patients is the common challenge. The main objective of this study was to establish local diagnostic reference levels for adult patients who visited abdominopelvic Computed Tomography examination. METHODS: A total of 158 patients who had taken abdominopelvic Computed Tomography examination from three selectedAmhara region hospitals were investigated. Both prospective and retrospective techniques of data collection were used while collecting the data in the entire sample. Two GE - Optima Computed Tomography 540 (16 slices) and one Phillips – Brilliance (64slices), were employed during data collections. Data for patient demographics scan protocols, Computed Tomography dose descriptors and machine specifications were collected and analyzed by using SPSS software version 26. RESULTS: The third quartile estimated computed tomography dose index volume and dose length product, which is the local Diagnostic Reference Levels, were 12 mGy and 1904 cm.mGy respectively. The investigated local Diagnostic Reference Levels of Computed Tomography Dose index volume (mGy) was comparable to other international Diagnostic Reference Levels. However, the third quartile value of dose length product (cm.mGy) was higher than other reported international Diagnostic Reference Levels. CONCLUSION: The values of local Diagnostic Reference Levels presented in this work can be used as a baseline upon which future dose measurements can be compared in Amhara region.

BACKGROUND: Early childhood radiation exposure carries an enhanced radiation risk of about two to three times as high as in adults. The objective of this study was to determine local diagnostic reference levels for the most frequent pediatric x-ray examinations in Addis Ababa, Ethiopia. METHODS: A cross-sectional study was conducted on 18 public and private hospitals/clinics in Addis Ababa. A total of 864 pediatric patients, undergoing eight types of routine x-ray examinations with 13 projections were evaluated from December 18/2017 to March 17 /2018. All pediatrics were categorized under four age groups. Anthropometric and radiographic parameters of each patient were recorded .The minimum, maximum, mean and third quartile values of entrance surface dose were analyzed using SPSS version 23. Finally, the suggested local diagnostic reference levels were compared with national and international reference dose values. RESULTS: Of the 864 pediatric patients, chest (AP/PA), lower and upper extremity (AP/PA) accounted for 501(58%), 110 (13%) and 103 (12%) respectively, accounting to 714(83%) of the total pediatric x-ray examinations. The suggested local diagnostic reference levels of chest X-ray (AP/PA) examinations in mGy were: (0.09,0.13,0.17,0.17) for age group (0

BACKGROUND: National and multinational surveys indicate large variability of Computed Tomography urinarytractStone doses. The wide use of abdominopelvic Computed Tomography in the diagnosis, raised the issue of radiation exposure. Hence,this study was conducted to assess Computed Tomography radiation exposure of urinary tract Stone Patients there by, to compare the results from established reference values and other published studies METHODS: A retrospective cross-sectional was done on 100 urinary tract Stone patients who have at least one computed tomography scan as part of their follow-up or for diagnosis purposes fromFebruary 1 to May 31, 2021, at Tikur Anbesa Specialized Hospital.Data were collected using a structured questionnaire format that evaluates the number of Computed Tomography they had, scan parameters, dose indicators, and socio-demographic characteristics. Finally, the collected data were analyzed using statistical software SPSS version 22 RESULTS: Out of 100 patients 3.6%of our patients have radiation exposure of more than 4mSv, which is the standard for low-dose Computed Tomography. The median radiation exposure is 1.27mSv per scan. Exposure factors like tube current, tube current products, dose length product, and scan range all have similar values with an almost null interquartile range. All the scans that overpassed the low dose threshold(4mSv) were done outsideTikur Anbesa Specialized Hospital. CONCLUSION: Our study showed that Tikur Anbesa Specialized Hospital's low-dose CT protocol for patients with urinary tract Stone is well optimized as opposed to non- Tikur Anbesa Specialized Hospital.

BACKGROUND: Breast cancer is the most common cancer type and the most common cancer related cause of death worldwide in women. This study was aimed to assess the awareness of mammography among breast cancer patients attending follow-up at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia. METHODS: Hospital based cross sectional study was conducted from July 01 to August 30, 2017 at Tikur Anbessa Specialized Hospital. Interviewer administered questionnaire was used to obtain data from 270 breast cancer patients who came to radiology department for follow up imaging. Collected data were checked for completeness, coded and entered into Epi Info 3.1 software and exported to SPSS Version 21 for analysis. RESULTS: Two hundred and twenty four (83%) of the study participants had no awareness of mammography while 46 (17%) of them had awareness of mammography. Out of the total 270 women, only 38(14.1%) had mammography test. In multivariate logistic regression analysis; level of education was found to have significant association with awareness of mammography. Women with breast cancer who completed secondary education were 4.5 times (AOR= 4.5; 95% CI: 1.39, 14.77) more likely to have awareness of mammography compared to women with breast cancer who were illiterate. CONCLUSION: This study revealed low awareness, knowledge and practice of mammography among women with breast cancer. Knowledge of participants about risk factor for breast cancer was also low.&nbsp

BACKGROUND: Various researchers who carried out national and international surveys have reported wide variations in patient dose arising from specific X-ray examinations. Thus, assessment of radiation dose is an essential part in the optimization process. The aim of this study was to compare the entrance surface doses delivered to pediatric patients undergoing digital and computed radiography X-ray examination.MATERIAL AND METHODS: A cross-sectional study was conducted on 389 pediatric X-ray projections less than 15 years of age on eight X-ray machines in Addis Ababa in February 2009 E.C. The tube output of the X-ray machines in air was measured using RaySafe XI dosimeters. Then, entrance surface dose was estimated for common x-ray examinations like chest, skull, extremities and pelvis using established relation between X-ray tube output and radiographic parameters. These data were analyzed statistically using computer (Excel and SPSS method).RESULT: The third quartile estimated ESDs in mGy for both computed and digital radiography examinations of chest (AP) for age (0-1 year) were 0.24 and 0.15, (1-5 year) 0.3and 0.16. For the age group (5-10 year), it was 1.97 and 0.26 and for the(10-15 year)group, 0.56 and 0.18 respectively.These values were higher than those of the United Nations Scientific Committee’s on the Effects of Atomic Radiation’s established dose reference levels(in mGy for age (0-1 year) 0.02, (1-5 year) 0.03, (5-10 year) 0.04, and (10-15 year) 0.05 respectively).CONCLUSION: The wider dose variation between computed and digital radiography shows that there is a pressing need to minimize the detriment caused by unnecessary computed radiography.

Purpose: To assess the frequency, appropriateness, and radiation doses associated with multiphase computed tomography (CT) protocols for routine chest and abdomen–pelvis examinations in 18 countries. Materials and Methods: In collaboration with the International Atomic Energy Agency, multi-institutional data on clinical indications, number of scan phases, scan parameters, and radiation dose descriptors (CT dose–index volume; dose–length product [DLP]) were collected for routine chest (n = 1706 patients) and abdomen–pelvis (n = 426 patients) CT from 18 institutions in Asia, Africa, and Europe. Two radiologists scored the need for each phase based on clinical indications (1 = not indicated, 2 = probably indicated, 3 = indicated). We surveyed 11 institutions for their practice regarding single-phase and multiphase CT examinations. Data were analyzed with the Student t test. Results: Most institutions use multiphase protocols for routine chest (10/18 institutions) and routine abdomen–pelvis (10/11 institutions that supplied data for abdomen–pelvis) CT examinations. Most institutions (10/11) do not modify scan parameters between different scan phases. Respective total DLP for 1-, 2-, and 3-phase routine chest CT was 272, 518, and 820 mGy·cm, respectively. Corresponding values for 1- to 5-phase routine abdomen–pelvis CT were 400, 726, 1218, 1214, and 1458 mGy cm, respectively. For multiphase CT protocols, there were no differences in scan parameters and radiation doses between different phases for either chest or abdomen–pelvis CT ( P = 0.40-0.99). Multiphase CT examinations were unnecessary in 100% of routine chest CT and in 63% of routine abdomen–pelvis CT examinations. Conclusions: Multiphase scan protocols for the routine chest and abdomen–pelvis CT examinations are unnecessary, and their use increases radiation dose.

BACKGROUND: Radiation from CT (computerized tomography), poses risk of radiation associated cancer. Studies indicate a cumulative dose of 50mGy triples the risk of leukemia and a dose of 60mGy triples the risk of brain tumors in children. This study aimed to assess the application of “Justification and Optimization Principles of ALARA (As Low As Reasonably Achievable)” in pediatric CT.METHOD: A prospective cross-sectional study was conducted from December 2017 to July 2018 G.C at Tikur Anbessa Specialized Hospital. CT request forms were reviewed. All pediatric patients listed for CT were included. The collected data were analyzed using SPSS version 25.RESULTS: Four hundred and twenty nine CT requests were reviewed, 246 (57.3%) were males and 183(42.7%) were females; 52(12.1%) were less than 1 year old, 153(35.7%) between 1 to 5 years, 113(26.3%) between 5 to 10 years and 111(25.8%) 10 to 14 years old. On the other hand, 28(6.5%) scan requests were rejected based on the ALARA justification principle, and from these, in 11(39.2%) MRI was recommended instead of CT, in 6(21.42%) US was recommended. Review of previous CT helped to reject 4(14.28%). Review of prior chest radiographs helped in rejecting 2(7.14%) requests. For 5(17.8%) and 19(4.4%), requests were optimized by applying principles of optimization to reduce received dose from CT.CONCLUSION: Overall, 47(11%) patients were protected from unnecessary radiation exposure by applying the principles of ALARA. The use of other alternating imaging modalities is vital in pediatric patients who are more radiosensitive and have longer time to manifest radiation induced injury.

Neurosurgeons often neglect the sphenoid sinus due to its deep location and difficulties in accessing during surgical interventions. Disease of the sphenoid sinus is difficult to diagnose since its presenting symptoms are difficult to recognize. Moreover, compared with other paranasal sinuses, the sphenoid sinus is considered the most variable air sinus in terms of its degree of pneumatization, number and position of inter-sinus septa, and its relationship with the surrounding anatomical structures. Anatomical variations of the sphenoid sinus are significant from a neurosurgical point of view. Understanding of these variations and its relationships with surrounding structures such as the internal carotid artery, optic nerve, and pituitary gland are clinically relevant to minimize injuries associated with surgical procedures that involve sphenoid sinus. We implemented principles of imaging using computed tomography to elucidate any anatomical variations of the sphenoid sinus in the Ethiopian population. We conducted a prospective study in 200 patients with ages 18&ndash, 79, who underwent scans of the sphenoid sinus at the Tikur Anbessa Referral Teaching Hospital in 2017&ndash, 2018. Our findings revealed an incidence of anatomographical variations in terms of pneumatization that varied between 2&ndash, 50%. These variants include 2% conchal, 25.5% presellar, 50% sellar, and 22.5% postsellar pneumatization. We also demonstrated anatomographic variants in terms of septation, 77.5% single complete septa, 11.5% single incomplete, 10% double septa, and 1% absence of septa. In summary, the sellar pneumatization was found to be the most clinically relevant anatomographic variant among Ethiopians participating in the study, of which 90% were tomographically single septated. These variants must be taken into consideration during trans-sphenoidal surgery and knowledge of the variations has clinical implication in minimizing injuries during invasive surgical procedures involving the sphenoid sinus.

BACKGROUND: The international literature on physicians’ knowledge regarding radiation dosages and risks due to computed tomography showed a widespread underestimation of diagnostic radiation doses. Hence, the objective of this work is to assess the awareness of pediatric residents and medical interns about pediatric CT dose and possible risks.METHODS: A cross-sectional study was conducted on May/2016 among year I to year III pediatric residents and 2015/2016 year medical interns attaching Pediatrics Department during the study period in Tikur Anbessa Specialized Referral and Teaching Hospital. Data was collected by distributing standardized structured questionnaires. Finally, after the data was checked for clarity and completeness, it was analyzed by using SPSS software.RESULT: While the majority (76.3%) of the residents and interns knew that children were more sensitive to radiation than adults, 93.7% did not know that there is currently no annual dose limit set for medical exposure of patients. The majority of the respondents (81.3%) know the risk of cancer from CT scan, but most (60%) of the respondents did not know that many imaging facilities still use adult doses for pediatric patients. Furthermore, 18.8% thought that magnetic resonance imaging involves ionizing radiation, and 8.9% of the physicians associated ultrasound examinations with ionizingradiation.CONCLUSION : Within resident group, since the level of clinical experience did not affect the outcome, we recommend that formal education and training on awareness of radiation with special concern on pediatric population is mandatory especially for pediatric residents and pediatricians who are major caretakers of children.KEYWORDS: Computed tomography, radiation exposure, awareness of radiation, pediatric CT dose, possible risks of radiation.

Objectives. To evaluate the level of knowledge about the radiation exposure to diagnostic imaging procedures among the final-year medical students and interns and to suggest how education could be improved. Material and Methods. All 355 final-year medical students and interns from Tikur Anbessa Teaching Hospital in Addis Ababa were included in the study. Participants were asked to complete a questionnaire consisting of their actual knowledge on ionizing radiation and on their preferred method of learning. All questions were in multiple choice formats ranging from 4 to 7 choices. The obtained data were analyzed using statistical software. Results. A total of 343 completed questionnaires were received. Up to 78.9% of respondents underestimated or do not know the radiation dose from commonly requested radiological procedures. Surprisingly, 245 (71.4%) and 254 (79.3%) students incorrectly believed that ultrasound and MRI, respectively, emit ionizing radiation or they do not know if they emit radiation or not. Both interns and medical students did not have significant difference (P=0.56) in their knowledge of ionizing radiation. A combination of tutorials or workshops (29.7%) and learning modules (19.8%) combined were their first and last preferred methods of teaching for future radiation awareness, respectively. Conclusion. This study has clearly shown that awareness of ionizing radiation from diagnostic imaging is lacking among senior medical students and interns. The results highlight the need for improved education to minimize unnecessary exposure of patients.

Breast cancer in women is a major health burden both in developed and developing countries. Although there is no cancer registry in Ethiopia cervical and breast cancers are the top two cancer types having a lion's share for the high maternal deaths in the country. Stratified random sampling with proportional allocation and systematic random sampling techniques were employed to assess the knowledge of breast cancer risk factors and practice of breast cancer screening methods among female healthcare professionals in governmental hospitals of Addis Ababa, Ethiopia. Data was analyzed using SPSS version 16 in bivariate analysis. In bivariate analysis age, marital status work experience and educational level had association with study participants' practice of the three breast cancer screening methods. These female health workers who were expected to act as role models and educate the public had adequate knowledge of breast cancer risk factors (85.0%)), BSE (77.6%), CBE (71.4%), and mammography (81.4%) but poor practice of BSE (35.5%), CBE (32.5%) and mammography (16%).Considering their leading role in breast cancer awareness and information dissemination, efforts should be made by Government to improve practice of breast cancer screening methods among female healthcare professionals.

Increasing concern has recently been expressed in the literature that the referring doctor's knowledge of radiation doses incurred during radiological procedures is inadequate. Such information may be particularly relevant when the expansion of imaging technology is considered. Hence the objective of this work is to assess the awareness of physicians about radiation dose and hazards of radiation. The study was performed among medical doctors at Tikur Anbessa Specialized Referral Teaching Hospital, the largest medical school in the country. A 135 self administered questionnaire was circulated randomly from a range of specialties; out of which 114 questionnaires were completed and used in the study giving a response rate of 85%. Participants were asked about the radiation dose from a chest radiograph, the annual dose from background radiation, and cancer risk from several common radiological procedures. A mean score of 7.1 out of 19 was achieved. 12 doctors had received formal training about ionizing radiation, and these participants scored higher than those with no previous training in this area. Our survey suggested that clinicians' awareness of radiation doses imparted during common radiological procedures, and the consequent risk to the individual patient is poor. A major curriculum revision of both undergraduate and graduate medical education regarding awareness on radiation is mandatory to improve this deficiency.

Background: A mammography examination facilitates the early detection of breast cancer. However, the potential risk of radiation-induced carcinogenesis is also increased with such a procedure. Thus assessment of the breast dose is important. Objectives: The objectives of this study were to investigate the techniques currently used for diagnostic mammography in Ethiopia, thereby to estimate the mean glandular dose (MGD) for Ethiopian women. Materials and methods: A cross-sectional study was conducted on breast cancer patients between 40-64 years of age having compressed breast thickness (CBT) greater than 2 cm. Five mammographic units and 386 women having a total of 1463 mammograms were included in the study period from April 2011-February 2012 in Addis Ababa, Ethiopia.The characteristics of the radiographic equipment and the exposure data of each patient were recorded using designed format. The MGD was calculated from the measured Entrance Surface Air Kerma (ESAK) using appropriate conversion coefficients. The obtained data were analyzed using statistical software. Results: The range of CBT was 2.2-7.5 cm for CC mammograms with mean ± SD of 4.24 ± 1.1 cm and 2.3-8.0 cm in MLO projection with mean ± SD of 4.64 ± 1.1 cm. The average MGD per exposure was 2.57 ± 2.1 mGy while the respective averages separately for the CC and MLO projections were 2.58 ± 2.2 mGy and 2.57 ± 2.1 mGy, respectively. Conclusion: The average MGD values recorded in this study were between the limiting value of the Institute of Physical Sciences in Medicine (2.0 mGy) and American College of Radiology (3.0 mGy) recommendation. These ensure that the mammography examination performed in Ethiopia was capable of achieving acceptable dose levels for patient safety.

BACKGROUND: A diagnostic reference levels (DRLs) form an efficient, concise, and powerful standard for optimizing the radiation protection of a patient. OBJECTIVES: To establish the first Ethiopian mammography diagnostic reference level (DRL) as a part of ongoing dose reduction program. MATERIALS AND METHODS: A cross‑sectional study was conducted on breast patients having compressed breast thickness (CBT) between 3.7 cm to 5.3 cm in Addis Ababa, Ethiopia. Five mammographic units and 755 mammograms were included in the study period. The mean glandular dose (MGD) was assessed for standard size breast substituted by different polymethyl methacrylate (PMMA) phantoms and imaged under typical clinical conditions in two mammography units. Peak kilo voltage (kVp) and entrance surface air kerma (ESAK) were measured using calibrated digital dosimeter Mult‑O‑Meter Unfors, model 535L, Sweden. The data were analyzed statistically. RESULT: The 3rd quartile value of all mammography units and that of private mammography units were found to be 2.37 and 1.73 milligray (mGy), respectively. Hospitals 3rd quartile values of MGD ranges between 1.57 to 7.21 mGy. The MDG based on 4.0 cm polymethyl methacrylate (PMMA) measurements was found to be 1.5 mGy. CONCLUSION: Both phantom and patient dose values indicated unnecessary high doses in one government mammography unit. For this mammography unit, urgent dose‑reduction measures and follow‑up actions were recommended.

Early childhood exposure carries an enhanced radiation risk and estimated that the probability of induction of cancer especially leukemia is about two to three times as high as in adults. Hence, dose measurement is mandatory for optimization in radiation protection to comply with international reference levels.To estimate pediatric patient's radiation dose arising from common diagnostic x-ray examinations by measuring Entrance Surface Dose, thereby, to compare the results from established reference values and other published studies.A cross-sectional study was conducted on pediatric patients under 15 years of age in Black Lion and Yekatite 12 Hospitals on May and August, 2009 respectively. Exposure factors used for commonly performed x-ray examinations like, chest, skull, abdomen, pelvis and spine were obtained from each Hospital. For each examination four age groups 0-1, 1-5, 5-10 and 10-15 years were studied. Entrance Surface Dose in air was measured using dositime dx X-ray Digital Dosimeter and Exposure Time Meter.In Black lion hospital, the lowest and the highest calculated mean Entrance Surface Doses in microGY were 104 and 2482 for chest Anteroposterior (0-1) years and lumbo-sacral lateral (10-15) years, respectively. In Yekatit 12 hospital, the lowest and the highest calculated mean Entrance Surface Doses in microGY were 200 and 3570 for chest antrioposterior (0-1) years and lumbo-sacral lateral (10-15)years, respectively. Wide variations of doses for the same type of examination and projection have been detected in each hospital.The wider dose variation suggests that there is a pressing need to seek dose optimization to children in order to reduce the detriment caused by the unnecessary high doses imparted to them.

Background: Medical x-ray exposures have the largest man made source of population exposure to ionizing radiation in different countries. Recent developments in medical imaging have led to rapid increases in a number of high dose xray examinations performed with significant consequences for individual patient doses and for collective dose to the population as a whole. It is therefore important in each country to make regular assessments of the magnitude of these large doses. Objectives: To calculate collective dose of the population as a result of radiation dose from diagnostic x-rays, thereby to estimate the annual incidence of cancer which would be reduced by the use of rare earth intensifying screen. Methods: Data on the number of diagnostic procedures using x-ray examination in year 2007 in nine governmental hospitals, excluding military hospitals, by body site were collected in Addis Ababa. The number of examinations of specific body site was multiplied by the average effective dose per examination to get the collective dose over the population. Based on International Commission on Radiological Protection (ICRP) the fatality risk of fatal cancers (5% per Sv) was estimated. Results: In this study, the annual collective dose over the population is 31.21manSv (0.0.42mSv per person). Based on ICRP fatality risk of 500 fatal cancers per 10,000 man-sieverts (5% per Sv), estimation of incidence of fatal cancers cases in year 2007 was 2 cases half of which can be reduced by adoption of rare earth screens. Conclusion: Although the use of ionizing radiation for diagnostic medical procedures is an acceptable part of modern medicine, there is also the potential for inappropriate use and unnecessary radiation dose to the patient, so the request of radiography must be justified. It is estimated that the adoption of rare earth screen technology might reduce the annual incidence of cancer which would be fatal after an average latency period of 18.4 years by half, hence this research recommended adopting rare earth screen technology in Ethiopia. [Ethiop. J. Health Dev. 2010;24(2):140-144]

The Local Diagnostic Reference Levels (LDRLs) form an efficient, concise and powerful standard for optimizing the radiation protection of a patient.To calculate the Entrance Surface Doses (ESDs) received by patients undergoing PA chest X-ray examinations in major public hospitals in Addis Ababa, thereby to establish the first Ethiopian LDRLs as part of ongoing dose reduction program.The entrance dose in air per examination was measured in eight hospitals comprising nine X-ray units and a sample of 192 radiographs. The entrance dose in air was measured using dositime dx X-ray Digital Dosimeter and Exposure Time Meter. The data were analyzedstatistically, and the minimum, median, mean, maximum, and third quartile values of ESDs are reported Finally, the proposed LDRLs are compared with the international reference dose values reported by the Commission for European Community (CEC), the International Atomic Energy Agency (IAEA) and the National Radiological Protection Board (NRPB).The third quartile value of the distribution of mean doses at individual hospitals participating in this survey is found to be 1.08 milligray (mGy). Hospitals mean ESDs for PA chest X-ray examination is found with the range of 0.0.76 to 1.48 mGy. Most of the ESD measured doses were slightly greater than the NRPB, CEC and IAEA reference doses.The results of the present study indicate a need for Quality Assurance (QA) programs to be undertaken to avert considerable cost and high patient doses. The results are useful to national and professional organizations and can be used as a baseline upon which future dose measurements may be compared.

Background: It is not uncommon to encounter patients undergo repeat x-ray examinations after their initial x-rays are rejected for poor image quality thereby subjecting them to excess radiation exposure and avoidable extra cost. This creates a situation which necessitates the need to explore causes of reject and repeat of x-ray examinations. The employment of reject analysis as part of overall Quality Assurance (QA) programmes in clinical radiography and radiology services in the evaluation of image quality is a well established practice. The role of reject analysis in providing relevant information that would help achieve sound reduction in radiation exposure and cost as well as develop acceptable image quality was explored in this study. Objective: To assess the reject rate of x-ray films and obtain information for further recommendation on quality, cost, and radiation exposure in the two hospitals. Methods: Prospective and cross-sectional study approaches were employed. Reject rate was measured for two x-ray departments (one from public and the other from private) across all plain x-ray films examinations using a structured format on which relevant data for reject were recorded by investigators (radiologists and a medical physicist). Results were then collected and entered into a database for analysis. Results: Reject rate along with exposure rate was measured across all plain film exams for the hospitals. Analysis has shown that the overall reject rate was 4.94% in 4470 and 0.83% in 1870 exposed films for the public and private hospitals, respectively. Conclusion: The study has shown the highest reject to be that of chest x-ray in both adults and children with overexposure and patient motion, respectively being the major causes. Although the overall reject rate is well within the accepted range, individual causes of reject have given light into some of the most common problems of quality of radiography service and we recommend that regular and cyclic QA programmes should be instituted at all levels of the x-ray department and that of hospital management for effective and sustained service delivery, x-ray dose reduction to patients and personnel as well as economic management of scarce resource. [Ethiop.J.Health Dev. 2008;22

To segment a 3D ultrasound image data that comprises extraction of surface of interests, smoothing of segmented image, thereby to estimate the surface area and volume of segmented 3D objects (e.g. fetus).(a) Seeded Region Growing (SRG) together with connectivity and marching cubes algorithms are used to segment the three dimensional (3D) ultrasound image data (I) (b) Using VTK (Visualization Tool Kit) a c++ program was developed which relies on the Maximum Unit Normal Component (MUNC) used for surface area measurement and Divergence Theorem Algorithms (DTA) used for volume estimation. The agreement between the program and the formula was tested on (1) computer generated spheres and cube (2) cylindrical shaped phantoms scanned by ultrasound scanner System Five, GE Vingmed (Horten, Norway) using a 3D annular array of 7.5 MHz. (3) 3D ultrasound fetus using cronbach alphaThe cylindrical shaped phantom (diameter 15.4 mm, length. 21.7 mm) with x and y voxel size 1.24921 mm and 0.613032 mm respectively and z voxel size 1.249221 mm yield a percentage error of 5.3% for the surface area and 2.6% for the volume. The volume and surface area of the fetus with x, y, z voxel size 0.465508mm, 0.529645 mm, 1.014201 mm respectively as estimated with the developed program was 3.758ml for volume and 1.937 mm2 fbr surface area, while the measured volume of fetus with EchoPAC-3D was 3.74 ml.It was concluded that. The agreement between the formula and the program for different shaped objects indicate that the methodology can provide measurements of the volume and the surface area of different anatomical structures.