Estimating of radiation output of X-RAY tube using mathematical model: Case of high-frequency machines.

PURPOSE: During any radiological procedure, it is important to know the dose to be-administered to the patient and this can be done by estimating the output of the X-ray tube either with a dosimeter or with a mathematical equation or Monte Carlo simulations. The aim of this work is to develop a new mathematical model equation (NMME) for estimating the output of high-frequency X-ray tubes. METHODS: To achieve this, data collected from ten machines in many regions of Cameroon were used (for nine machines) to build an initial model that does not take into account the anode angle and the tenth machine was used to test the model. Using the SpekCalc software, some simulations were carried out to evaluate the influence of the anode angle. This allowed the NMME to be proposed. RESULTS: The deviations frequencies between 0.65% and 19.61% were obtained by comparing the output values obtained using initial model with the measured values. The statistical hypothesis test showed that the estimated values using initial model and NMME are in agreement with those measured unlike the Kothan and Tungjai model. For the tenth machine, the percentage difference between estimated and measured values is less than 8 %. CONCLUSION: These results show that the proposed model performed better than the previous models. In the absence of a dosimeter, the NMME could be used to estimate the output of high frequency X-ray machines and therefore the radiation doses received by patients during diagnostic X-ray examinations.

A review of MRI studies in Africa with special focus on quantitative MRI: Historical development, current status and the role of medical physicists.

This scoping review provides overview on the historical and major developments, current status, quantitative magnetic resonance (MR) studies and the role of medical physics bodies in MR imaging in Africa. The study analyzed MRI availability in 32 (59 %) of the 54 African countries. South Africa and Egypt have the most dominant MR systems. Number of MR systems in the 4 northern countries (Egypt, Morocco, Algeria and Libya) alone constitute 53 % of the total number of machines in the studied countries. Less than one-third of the countries have 1 MR system serving less than a million population. Libya recorded the most MR systems per million population. The studied countries altogether have an average of 1 machine per million population. The private sector far dominates number of installed MR systems across the region, making up two-thirds of the distribution. A major challenge was revealed where less than 3 % of Medical Physicists in the studied countries are engaged in MRI facilities. Review of MRI published studies in the last 5 years indicates dominance of literature on brain studies and most of such published works coming from Nigeria. Only 7 out of 27 published studies reviewed were quantitative. The African region has no dedicated MRI physics societies; however, the regional medical physics body and national associations have big roles to play in developing MRI through education, research, training and leveraging on awareness creation. Thisreview is the first of such wide scale study on MRI availability and quantitative studies in the African region.

ESTABLISHMENT OF LOCAL DIAGNOSTIC REFERENCE LEVEL FOR ROUTINE PAEDIATRIC COMPUTED TOMOGRAPHY EXAMINATIONS IN BAFOUSSAM WEST CAMEROON.

The main purpose of this study was to determine local diagnostic reference level (LDRL) for routine computed tomography (CT) examination in Bafoussam, western Cameroon. The exposure parameters and dose quantities were collected manually. This retrospective, evaluative and comparative study was conducted to determine LDRLs for routine head CT examination in Bafoussam, to optimize these procedures in the region. The 75th percentile values of the calculated volume CT dose index (CTDIvol) and dose length product (DLP) were proposed as LDRL. The sample was classified in four age groups: < 1, 1-5, 5-10 and 10-15 y. The LDRLs obtained for the four age groups were: 24 mGy and 381.32 mGy.cm, 42.5 mGy and 875.55 mGy.cm, 45.85 mGy and 939.62 mGy.cm, 57.12 mGy and 1222.3 mGy.cm, respectively. The 75th percentile CTDIvol and DLP dose values for this study are higher than international values. We propose a coordinating discussions and collaboration about patient's and specific equipment's change information's, between radiologists, medical imaging technicians and medical physicist, which can reduce absorbed doses and improved medical practice in hospitals.