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.

Assessment of heavy metals' pollutions and potential risks associated to the rocks of Pouma subdivision-Cameroon.

The present study aimed to assess the ecological and health risks of the Pouma rock samples. Twenty-three (23) trace element concentrations were evaluated. The concentrations of these trace elements were compared with those of quartzite from other countries and with global reported values. When compared with the world values, the concentrations of trace metals were below the world average values except that of Barium. The ecological risk assessment was carried out using the geo-accumulation index, contamination factors and the potential ecological risk index. The geo-accumulation index and contamination factors showed that the quartzite of Pouma subdivision are not polluted and not contaminated by the investigated metal except for Barium and Mercury. The health risk assessment using the USEPA (United States Environmental Protection Agency) method showed that there is a possible non-carcinogenic risk from Al2O3 (for children and adults) and from Cr for Children. However, there is a tolerable and high carcinogenic risk due to Cr for adults and children, respectively. It was found independently for non-carcinogenic and carcinogenic risk that the exposure via the ingestion route is the most dangerous for adults and children.