Citation: Nkubli FB, Nzotta CC, Nwobi NI, Moi SA, Adejoh T, Luntsi G, et al. A survey of structural design of diagnostic x-ray imaging facilities and compliance to shielding design goals in a limited resource setting. J Glob Radiol. 2017;3(1):Article 6.

Abstract

Diagnostic Reference Levels (DRLs) for digital mammography and image quality evaluation are important optimization tools in medical imaging. High quality mammograms are essential to the successful early detection of breast cancer. The objective of the study is to establish DRLs for digital mammography and to assess image quality of the mammograms for optimization. DRLs were established using thermoluminescent dosimeter (TLD) chips to estimate the mean glandular dose for both cranio-caudal and medio-lateral oblique projections. The TLD chips were calibrated. The DRLs were set at the 75th percentile of the distribution of the median value of mean glandular dose. Image quality was assessed using European Commission guideline for mammographic image quality assessment. Results for DRLs were 0.53 mGy for cranio-caudal and also 0.53 mGy for medio-lateral oblique. Image quality evaluation showed criteria scores for cranio-caudal and medio-lateral oblique projections as 76 % and 61.2 % respectively. The mammograms scored the highest and lowest score of 100 % and 44 % on criteria 2 and criteria 6 (absence of skin fold) respectively for cranio-caudal projections while for the mediolateral oblique projections, criteria 1 (all breast tissue clearly shown) and criteria 5 (inframammary angle clearly demonstrated) have the highest and lowest score of 96 % and 8 % respectively. The study showed that the DRLs in this study was lower than the established values in other regions of Nigeria and international established values. Image quality was within acceptable level. DRLs for digital mammography and image quality evaluation are important optimization tool that should be adopted by every radiology department with mammography unit.

Background: MRI plays a vital role in diagnosis of diseases. Objectives:To determine the pattern of imaging requests and findings from MRI scans of patients in the bauchi State Hospital. Methods:A prospective cross-sectional study of MRI request forms and findings of 138 patients was conducted from August 2016 to January 2017. MRI scans were performed using a 0.35T Neusoft MRI scanner and reported by a group of consultant radiologists. Data were analysed using descriptive statistics with the computer software SPSS version 22 (IbM, New York, USA). Results:This study revealed that majority of the MRI requests were for lumbosacral spine examinations (n=84, 60.9%), followed closely by MRI of the brain (n=42, 30.4%) and thirdly shoulder and abdomen examinations with a frequency of 4.3% each. Out of 138 MRI scans studied, intervertebral disc prolapse (n=60, 43.5%) was the commonest finding from MRI scans of patients, the second most prevalent finding was L4-L5 degenerative disc disease (n=12, 8.7%). Intramuscular lipoma and basal ganglia edema had a prevalence of 4.3%. Conclusion:The commonest requests were MRI lumbosacral and, in terms of findings, we found intervertebral disc prolapse, L4-L5 degenerative disc disease, basal ganglia edema and intramuscular lipoma as the major findings from MRI scans in bauchi.

PurposeDiagnostic Reference Level (DRL) is a practical tool for radiation dose optimization, yet it does not indicate the patient size or image quality. The Acceptable Quality Dose (AQD) introduced to address the limitations of the DRLs and it is based on image quality, radiation dose, and patient weight. The aim of this study is to establish the AQD for adult patients' undergoing Computed Tomography (CT) examinations (Head, chest, abdomen).MethodsThis study is conducted in the four main hospitals at the Ministry of Health and Prevention. Patient information and exposure parameters were extracted. All the acceptable images are scored for their quality assessments. Data is classified as seven weight groups, <50, 50–59, 60–69, 70–79, 80–89, 90–99, and ≥100 kg. The mean ± SD, median, and 75th are calculated for the CTDIvol and DLP for each weight group per examination.ResultsOut of 392, 358 CT examinations are scored with acceptable quality. The median CTDIvol values for the weight groups are obtained as 24.6, 25.4, 25.4, 25.0, 26.0, 27.0, and 29.0 mGy. Moreover, median DLP values are obtained as 576.7, 601.0, 616.5, 636.1, 654.0, 650.0, 780.0, and 622.5 mGy.cm, respectively, for head CT without Contrast Media (CM). Similar calculation for head CT with (CM), chest without CM, abdomen without CM, and chest and abdomen (with and without CM) CTs are presented.ConclusionImages with bad, unacceptable and higher than necessary qualities contribute to increasing patient dose and increasing the DRLs. The AQD for the selected examinations were lower than the proposed DRLs in the United Arab Emirates. The integration of image quality and patients size in the assessment of the AQD values provide effective model to compare radiation dose indices within facility and compare with others. The obtained results may be useful in terms of improving dose and the diagnostic quality in the national and international levels.