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. The diagnostic reference values of ESAK for digital radiography were 0.31 mGy (chest PA), 4 mGy (lumbar spine AP), 5.4 mGy (lumbar spine LAT), 3.8 mGy (abdomen AP) and 2.4 mGy (pelvis AP). For computed radiography, the mean ESAK ranges were 0.44-0.57 mGy (thoracic AP), 3.59-3.72 mGy (lumbar spine AP), 6.16-6.35 mGy (lumbar spine LAT), 3.89-3.44 mGy (abdominal AP) and 2.92-3.47 mGy (pelvic AP). In conclusion, high ESAK variations show the potential for optimising protection in digital radiology.

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. The estimated median values of MGD ranged from 1.5 to 3.9 mGy for craniocaudal projection for median range of 15-59 mm compressed breast thickness (CBT). For a CBT range of 15-63 mm, the median MGD value was 1.5-5.1 mGy for medio-lateral oblique projection. Comparison with other studies showed that the MGD values obtained in this study were relatively high. The magnitude and wide variation of the exposure parameters suggest existing potential for optimization. The training of radiology staff was identified as a top priority.

Radiation exposure during CT procedures in Tanzania.

The aim of this study was to evaluate optimisation status during common computed tomography (CT) procedures by determining values of volume computed tomography dose index (CTDIvol) and dose-length product (DLP) per examination. Patient and exposure data were collected from the CT console during various CT procedures. The results show that variations in CTDIvol and DLP values were mainly because of differences in the techniques used. The 75th percentile values were set as the third quartile of the median CTDIvol or DLP values for all hospitals. These values of 40.9, 9.0, 9.4 and 16.2 mGy for CTDIvol were determined for head, high-resolution chest, abdomen-pelvis and lumbar spine, respectively. The corresponding DLP values for the same sequence of CT procedures were 900, 360, 487 and 721 mGy.cm, respectively. The updated results provide a basis for optimising the procedures of CT in this country.

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 0.64 to 1.55 mSv and broadly comparable to data in the previous analysis. Over seven year period, the maximum annual individual dose was 4 mSv and therefore below the dose limit of 20 mSv y-1. The impact of radiological practice on the exposed population was <1.1 person.Sv. The results demonstrate satisfactory radiation protection conditions at workplaces, a situation which is mainly explained by the existing effective regulatory enforcement and improved workers' awareness.

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. AIM: The aim of this study was to investigate the status of implementation of the QC measures as performed by radiographers in diagnostic radiography departments in Tanzania. METHOD: A quantitative cross-sectional survey, using a questionnaire, was conducted on a sample of 84 radiographers who had been trained in the QC programme and who were practising in 54 hospitals within Tanzania. RESULTS: A large number of respondents were not implementing the following QC tests: tube output, kV, mAs and timer (94%), collimation (53.5%), and densitometry and sensitometry (87.7%). The tests for film viewing box and lead rubber protective apparel were not implemented by 64.2% and 59% of the respondents, respectively. The cassette inspection and darkroom inspection were reported as being implemented by most respondents, although the testing was not observing the recommended schedule. Furthermore, the departments had no records and procedures for the QC programme, and only the locally improvized QC test tools were reported to be available. CONCLUSION: The QC training objectives of TAEC have not been largely achieved because radiographers are not adequately implementing the QC programme. Without the QC programme in place, equipment malfunctioning will not be revealed at an early stage, and this can cause poor image quality and/or higher dose to patients. Therefore, active involvement of the TAEC, the ministry of health, hospital management teams, and radiographers is desirable to achieve full implementation of the programme.