Radiation dose to breast during digital mammography in Tanzania.

The aim of this study was to evaluate the mean glandular dose (MGD), to assess the potential for optimization, and to propose diagnostic reference levels (DRLs). MGD was estimated from air kerma measurements and patient information collected during mammography examinations. The 75th percentile values were determined as the third quartile of the median MGD values for all hospitals, and DRLs set as 75th percentile of MGD values.

Entrance surface air kerma to patients during digital radiographic examinations in Tanzania.

The aim of this study was to determine the entrance surface air kerma (ESAK) in adult patients during digital radiography and to evaluate the optimisation potential in five common X-ray examinations in Tanzania. Based on a sample of 240-610 patients, ESAK was estimated using X-ray tube output measurements, patient information and backscatter factors. The results show that the mean ESAK values were higher or comparable to data from the literature.

Determination of Dose Distributions by Monte-Carlo Simulation of 6 MV Photon Beam of Varian VitalBeam Accelerator Using Geant4 Multithreaded Code.

Background: Accuracy of dose delivery in radiation therapy is a primary requirement for effective cancer treatment. In practice, dose delivery accuracy of ±5% is desired. To achieve this accuracy level, an accurate method for calculating the dose distributions in the tumor volume is required.

ESTIMATION OF PATIENT RADIATION DOSES FROM MULTI-DETECTOR COMPUTED TOMOGRAPHY ANGIOGRAPHY PROCEDURES IN TANZANIA.

The aim of the present study was to estimate the volume CT dose index (CTDIvol), dose length product (DLP) and effective dose (ED) to patients from five multi-detector computed tomography angiography (MDCTA) procedures: brain, carotid, coronary, entire aorta and lower limb from four medical institutions in Tanzania; to compare these doses to those reported in the literature, and to compare the data obtained with ICRP 103 and Monte Carlo software. The radiation doses for 217 patients were estimated using patient demographics, patient-related exposure parameters, the geometry of examination and CT-Expo V 2.4 Monte Carlo-based software.

OCCUPATIONAL EXPOSURE TO EXTERNAL IONISING RADIATION IN TANZANIA (2011-17).

The objectives of this paper were to evaluate the occupational radiation exposure data from 2011 to 2017 and to compare the results with status in 1996-2010 periods. The evaluation was performed in terms of annual collective effective dose, the average annual effective dose, the individual dose distribution ratio and the annual collective effective dose distribution ratio. Irrespective of work category, the results indicate that the average effective dose ranged from 0.

CHALLENGES IN CLINICAL PRACTICE OF CR MAMMOGRAPHY IN TANZANIA.

The aim of this study was to evaluate the clinical practice of CR mammography in Tanzania. The equipment performance and operational conditions were studied; and mean glandular dose (DG) estimated to 75 women undergoing diagnosis at three mammography facilities. All mammograms during this study were reported to be useful for the intended diagnosis.

Review of the current status of radiation protection in diagnostic radiology in Africa.

The aim of this paper is to review the available published studies from African countries on patient doses and medical radiation protection and identify strengths, weaknesses, and challenges. Papers on radiation doses to patients published until 2016 pertaining to studies in African countries were reviewed. Radiography, interventional radiology, computed tomography (CT), and mammography modalities were covered.

Defining the diagnostic divide: an analysis of registered radiological equipment resources in a low-income African country.

Introduction: Diagnostic radiology is recognised as a key component of modern healthcare. However there is marked inequality in global access to imaging. Rural populations of low- and middle-income countries (LMICs) have the greatest need.

Assessment of patient dose and optimization levels in chest and abdomen CR examinations at referral hospitals in Tanzania.

The aim of this study was to evaluate the radiation doses to patient during chest and abdomen CR examinations, and assess the related level of optimization at five referral hospitals in Tanzania. The international code of practice for dosimetry in diagnostic radiology was applied to determine the entrance surface air kerma (ESAK) to patients. The level of optimization was assessed from low-contrast objects scores of phantom images at different exposures.

Quality Control Measures in Tanzania: Is it Done?

Background: Regular implementation of a quality control (QC) programme in diagnostic radiology is vital if consistent optimal equipment performance, quality images, and accurate diagnosis at optimum radiation dose and costs are to be achieved. This highlighted the necessity for the Tanzania Atomic Energy Commission (TAEC) to establish a training programme to enable radiographers to implement a QC programme in their departments because there are no clinical medical physicists in diagnostic radiology in the country. However, the status of programme implementation is not precisely known.

Application of off-line image processing for optimization in chest computed radiography using a low cost system.

 The objective of this study was to improve the visibility of anatomical details by applying off-line postimage processing in chest computed radiography (CR). Four spatial domain-based external image processing techniques were developed by using MATLAB software version 7.0.

A study to establish international diagnostic reference levels for paediatric computed tomography.

The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of computed tomography dose index (CTDI vol) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y.

Paediatric doses during some common X-ray procedures at selected referral hospitals in Tanzania.

The aim of this study was to determine the radiation doses to paediatric patients of different age groups at three large hospitals for optimisation purposes. The entrance surface air kerma (ESAK) values were determined from the measured X-ray output values using calibrated ionisation chamber, TW 233612 and clinical patient parameters. The air kerma-area product (KAP) values were measured using a calibrated Diamentor E2 system.

IAEA survey of paediatric computed tomography practice in 40 countries in Asia, Europe, Latin America and Africa: procedures and protocols.

Objective: To survey procedures and protocols in paediatric computed tomography (CT) in 40 less resourced countries.

Methods: Under a project of the International Atomic Energy Agency, 146 CT facilities in 40 countries of Africa, Asia, Europe and Latin America responded to an electronic survey of CT technology, exposure parameters, CT protocols and doses.

Results: Modern MDCT systems are available in 77 % of the facilities surveyed with dedicated paediatric CT protocols available in 94 %.

Occupational radiation exposure in Tanzania (1996-2010): status and trends.

Data on occupational radiation exposure using the thermoluminescence dosimetry methodology in Tanzania for the years 1996-2010 are analysed and discussed. The results of the analysis indicate that over 80 % of the total collective dose was from diagnostic radiology. In addition, <1 % of workers received annual individual doses above 5 mSv, and there were no doses that exceeded the recommended limit of 20 mSv y(-1), except for one incidence in non-destructive testing.

IAEA survey of pediatric CT practice in 40 countries in Asia, Europe, Latin America, and Africa: Part 1, frequency and appropriateness.

Objective: The purpose of this study was to assess the frequency of pediatric CT in 40 less-resourced countries and to determine the level of appropriateness in CT use.

Materials And Methods: Data on the increase in the number of CT examinations during 2007 and 2009 and appropriate use of CT examinations were collected, using standard forms, from 146 CT facilities at 126 hospitals.

Results: The lowest frequency of pediatric CT examinations in 2009 was in European facilities (4.

Performance evaluation of three computed radiography systems using methods recommended in American Association of Physicists in Medicine Report 93.

The performances of three clinical computed radiography (CR) systems, (Agfa CR 75 (with CRMD 4.0 image plates), Kodak CR 850 (with Kodak GP plates) and Kodak CR 850A (with Kodak GP plates)) were evaluated using six tests recommended in American Association of Physicists in Medicine Report 93. The results indicated variable performances with majority being within acceptable limits.

Initial quality performance results using a phantom to simulate chest computed radiography.

The aim of this study was to develop a homemade phantom for quantitative quality control in chest computed radiography (CR). The phantom was constructed from copper, aluminium, and polymenthylmethacrylate (PMMA) plates as well as Styrofoam materials. Depending on combinations, the literature suggests that these materials can simulate the attenuation and scattering characteristics of lung, heart, and mediastinum.

Paediatric CT examinations in 19 developing countries: frequency and radiation dose.

The aims of this study were to investigate the frequency of computed tomography (CT) examinations for paediatric patients below 15 y of age in 128 CT facilities in 28 developing countries of Africa, Asia and Eastern Europe and to assess the magnitude of CT doses. Radiation dose data were available from 101 CT facilities in 19 countries. The dose assessment was performed in terms of weighted CT dose index (CTDI(w)), volume CT index and dose length product (DLP) for chest, chest (high resolution), lumbar spine, abdomen and pelvis CT examinations using standard methods.

Patient doses in CT examinations in 18 countries: initial results from International Atomic Energy Agency projects.

The purpose of this prospective study at 73 facilities in 18 countries in Africa, Asia and Eastern Europe was to investigate if the CT doses to adult patients in developing countries are higher than international standards. The dose assessment was performed in terms of weighted computed tomography dose index (CTDIw) and dose length product (DLP) for chest, chest (high resolution), lumbar spine, abdomen and pelvis CT examinations using standard methods. Except in one case, the mean CTDIw values were below diagnostic reference level (DRL) while for DLP, 17 % of situations were above DRLs.

Patient doses in radiographic examinations in 12 countries in Asia, Africa, and Eastern Europe: initial results from IAEA projects.

Objective: The purpose of this study was to survey image quality and the entrance surface air kerma for patients in radiographic examinations and to perform comparisons with diagnostic reference levels.

Subjects And Methods: In this multinational prospective study, image quality and patient radiation doses were surveyed in 12 countries in Africa, Asia, and Eastern Europe, covering 45 hospitals. The rate of unsatisfactory images and image quality grade were noted, and causes for poor image quality were investigated.

Application of European protocol in the evaluation of contrast-to-noise ratio and mean glandular dose for two digital mammography systems.

The performance of two digital mammography systems, Agfa CR75 and CRMM3 computed radiography (CR) and IMS Giotto MD direct digital radiography (DR), was assessed by applying a method recommended in the European protocol for quality control in mammography screening. The contrast-to-noise ratio (CNR) and mean glandular dose (MGD) values were measured and contrast detail (CD) analysis was performed. The CNRs for system CR were 21.

Radiation doses to patients during selected CT procedures at four hospitals in Tanzania.

The dose characteristics of CT scanners from local scanning protocols were investigated on the basis of questionnaire information provided by four hospitals conducting CT procedures in Tanzania. The information included scanner model, scanner manufacturer, number of most frequent CT examinations and the employed scanning parameters to previously diagnosed patients. For each scan technique, patient doses were estimated in terms of computerized tomography dose index, dose length product and effective dose using the software developed by the ImPACT scan group in conjunction with the NRPB conversion coefficients data.