background: due to volatility of radioactive iodine solutions, usually internal exposure would occur in personnel that are working in nuclear medicine centers. the activities in the thyroid of individual s who work in nuclear medicine centers of north west provinces of iran were measured using nai (sodium iodide) detectors. in every center, nearly 40 - 500 mci of 131 i and 50 - 600 μ ci of 125 ...

A new detector design using pixelated NaI(Tl) crystals has been evaluated for use in positron emission tomography (PET). This detector uses 4 4 30 mm NaI(Tl) pixels coupled via a lightguide (1.4 cm thick) to an array of 39 mm diameter photomultiplier tubes (PMTs) in an Anger detector design. Our measurements show that the high light output of NaI(Tl) leads to a good discrimination of the 4 mm N...

In this work we calibrated the NaI(Tl) scintillation detectors (5.08 × 5.08 cm and 7.62 × 7.62 cm) and the Full Energy Peak Efficiency (FEPE) for these detectors have been calculated for point sources placed at different positions on the detector axis using the analytical approach of the effective solid angle ratio. This approach is based on the direct mathematical method reported by Selim and ...

Mass attenuation coefficients of the some elements were determined for two photon energies using different three detectors. The samples were irradiated using 10 mCi Cd-109 and 100 mCi Am-241 radioactive point sources. The photons were separately counted by Si(Li), NaI(Tl) and Cd(Tl) detectors. It was observed that the mass attenuation coefficient decreases with increasing energy and increases w...

The DAMA experiments are running deep underground in the Gran Sasso National Laboratory. Several interesting results have been achieved so far. Here a maximum likelihood method to search for the WIMP annual modulation signature is discussed and applied to a set of preliminary test data collected with large mass highly radiopure NaI(Tl) detectors. Various related technical arguments are briefly ...

BACKGROUND Cadmium zinc telluride (CZT) solid-state detectors have been recently introduced in the field of nuclear medicine in cardiology and breast imaging. The aim of the current study was to evaluate the performance of the novel detectors (CZT) compared to that of the routine NaI(Tl) in bone scintigraphy. A dual-headed CZT-based camera dedicated originally to breast imaging has been used, a...

In view of assessing natural radioactivity with on-site quantitative gamma spectrometry, efficiency calibration of NaI(Tl) detectors is investigated. A calibration based on Monte Carlo simulation of detector response is proposed, to render reliable quantitative analysis practicable in field campaigns. The method is developed with reference to contact geometry, in which measurements are taken pl...