The study found that the activity concentrations of the radionuclides 238U, 232Th and 40K in the sandstone are 32 ± 13, 29.6 ± 12.2, and 132.6 ± 86.4 Bq kg-1, respectively. These values are lower than the reported worldwide limits of 33, 45, and 412 Bq kg-1. According to the present study, the absorbed dose rate (Dair), the annual effective dose, and the excess life time cancer were all found to be below the worldwide mean. Pearson correlation, PCA, and HCA were used to analyze the data and identify patterns in the relationship between radionuclides and radiological hazards. A statistical analysis of the sandstones showed that the radioactive elements 238U, 232Th and 40K are the main contributors to the radioactive risk. The study suggests that the sandstone is safe to use. The levels of radioactivity are not high enough to pose a risk to human health.
BACKGROUND AND AIMS: Many patients who presented to Universiti Kebangsaan Malaysia Medical Centre (UKMMC) with signs and symptoms of urolithiasis had mild hydronephrosis with non visualization of calculus on ultrasound examination. These patients underwent an intravenous urogram (IVU) in order to determine the presence of urolithiasis and most of them had normal IVU. The main aim of this study was to determine the predictive value of urinalysis in this group of patients in determining the need for IVU examinations.
MATERIALS AND METHODS: Retrospectively the ultrasound, urinalysis and intravenous urography reports of 53 patients were reviewed and evaluated.
RESULTS: The positive predictive and negative predictive value of urinalysis was found to be 68% and 96.4%, respectively. CONCLUSIONS; The results indicate that the urinalysis was an excellent negative predictor for IVU. In view of high radiation dose, risk of contrast reaction and contrast induced nephropathy of IVU, we suggest that it should not be performed in patient with non visualization of calculus mild hydronephrosis when the urinalysis is negative for blood.
Study site: Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM)