The main objective of this research is to introduce a newly developed device called as "Adaptive Quality Control Phantom" (AQCP) that designed to perform the QC tests. AQCP is a computer-controlled phantom which positions and moves a radioactive source in the FOV of an imaging nuclear medicine device on a definite path to produce any spatial distribution of gamma rays to simulate QC phantoms. To establish and prove the proper functionality as well as the accurate performance of AQCP, different tests including systematic uniformity, collimator hole angulation and the center of rotation tests have been conducted by this device and then the results, findings and differences of such testing when comparing to what achieved by the QC classic method tests have been discussed and analyzed in detail in this paper. According to the different tests done by AQCP, the authors found that the performance of systematic uniformity test shows a considerable reduction in the technologist dose compared to the IAEA-TECDOC-602 method. The collimator hole angulation for LEHR, LEUHR and LEHS collimators were measured by using a point source and the computer-controlled cylindrical positioning and the results achieved indicate that the measurement accuracy for absolute angulation errors was better than 0.018 degrees. A method for center of rotation assessment by AQCP was introduced, the results of such proposed method compared to the routine QC test and their differences have been discussed in detail. Based on all discussed in this paper regarding AQCP, the authors suggest that their presented device would be able to simulate QC phantoms.

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One of the important parameters for establishing charge particle equilibrium (CPE) conditions of free-air ionization chamber is an electric field distribution. In this paper, electric field distribution inside the ionization chamber was investigated by finite element method. For this purpose, the effects of adding guard plate and guard strips on the electric field distribution in the ionization chamber were studied. it is necessary to apply a lead box around the ionization chamber body to avoid of scattered radiation effects on the ionization chamber operation, but the lead box changes the electric field distribution. In the following, the effect of lead box on the electric field distribution was studied. Finally, electric field distribution factor (k field ) was calculated by the simulation. The results of the simulation showed that presence of the guard plate and guard strips, and applying a suitable potential to lead box, a convergence of k field to 1 was achieved. K: Detector modelling and simulations II (electric fields, charge transport, multiplication and induction, pulse formation, electron emission, etc); X-ray detectors 1Corresponding author.

The main objective of this research is to introduce a newly developed device called as "Adaptive Quality Control Phantom" (AQCP) that designed to perform the QC tests. AQCP is a computer-controlled phantom which positions and moves a radioactive source in the FOV of an imaging nuclear medicine device on a definite path to produce any spatial distribution of gamma rays to simulate QC phantoms. To establish and prove the proper functionality as well as the accurate performance of AQCP, different tests including systematic uniformity, collimator hole angulation and the center of rotation tests have been conducted by this device and then the results, findings and differences of such testing when comparing to what achieved by the QC classic method tests have been discussed and analyzed in detail in this paper. According to the different tests done by AQCP, the authors found that the performance of systematic uniformity test shows a considerable reduction in the technologist dose compared to the IAEA-TECDOC-602 method. The collimator hole angu-lation for LEHR, LEUHR and LEHS collimators were measured by using a point source and the computer-controlled cylindrical positioning and the results achieved indicate that the measurement accuracy for absolute angulation errors was better than 0.018 degrees. A method for center of rotation assessment by AQCP was introduced, the results of such proposed method compared to the routine QC test and their differences have been discussed in detail. Based on all discussed in this paper regarding AQCP, the authors suggest that their presented device would be able to simulate QC phantoms.

The parallel-plate free-air ionization chamber termed FAC-IR-300 was designed at the Atomic Energy Organization of Iran, AEOI. This chamber is used for low and medium X-ray dosimetry on the primary standard level. In order to evaluate the air-kerma, some correction factors such as electron-loss correction factor (k e ) and photon scattering correction factor (k sc ) are needed. k e factor corrects the charge loss from the collecting volume and k sc factor corrects the scattering of photons into collecting volume. In this work k e and k sc were estimated by Monte Carlo simulation. These correction factors are calculated for mono-energy photon. As a result of the simulation data, the k e and k sc values for FAC-IR-300 ionization chamber are 1.0704 and 0.9982, respectively. K: Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc); Detector modelling and simulations II (electric fields, charge transport, multiplication and induction, pulse formation, electron emission, etc); Gaseous detectors; X-ray detectors 1Corresponding author.