مشروع البحث: Radiation dose Risk Factor from Dental Materials in Libya
تحميل...
المساهمين
الممولين
رقم التعريف
6999
الباحث
نجلاء عمران محمد كحيل
الوصف
A preliminary study was conducted to determine thorium, uranium and potassium elemental concentrations in surface of different types of zirconia powder materials used for dental prosthetics restoration, mainly feldspathic, zirconia-based ceramics. Ten different samples from various manufacturers that has been imported to be used in various dental laboratories in Tripoli-Libya. These samples were investigated with regard to content of natural radionuclides by means of gamma spectrometry using high-resolution γ- ray spectrometry.
The samples were weighed and measured in the "EGA" laboratory in terms of their gamma radioactivity for a counting time of 15 hours each. From the measured γ-ray spectra, elemental concentrations were determined for uranium from 2.34 to 16.77 Bq.kg1 which is equivalent to ( 0.19 – 1.4ppm) and for thorium range from 1.75 to 17.4 Bq.kg1 which is also equivalent to ( 0.43- 4.3ppm), and for potassium from 2.9 to 23.49 Bq.kg-1 which is equivalent to (934-1706 ppm). The calculated total average radionuclide activities for all samples were calculated and presented in Table 6.1. From this Table it can be seen that sample No.1 has shown the lowest calculated value of (3.43±0.5) while sample No.2 presented the highest calculated value of (86±9) from all measured samples. The other samples can be presented in an ascending order of calculated activities Zir10, Zir5, Zir3, Zir4, Zir9, Zir7, Zir6, Zir8. For the purpose of comparison with International presented values using Equation No.1 the activities were transferred in terms of ppm and were presented in Table 6.2. The final presented data were found to be from 0.19ppm to 1.4ppm for uranium, while found to be from 0.33ppm to 0.60ppm for thorium and found to be 137ppm to 8050ppm for potassium. It is also worth noting that the dose rates and absorbed dose effects of these calculated radionuclides was found to be 0.05- 1.0mSv.year-1
الكلمات الدالة
Radiation dose Risk Factor from Dental Materials in Libya