introduction: in diagnostic and therapeutic procedures, dosimetric studies are performed on the dosimetric systems in order to comply the radiation safety standards. monte carlo methods are used due to the high complexity and cost of patient-specific phantom construction. the high complexity of the digitized phantoms greatly increases the time and computational task of the monte carlo calculati...

introduction accurate estimation of the absorbed dose in radiosensitive organs, located away from the target volume during radiotherapy, is one of the main reasons for the development of reference phantoms. the international commission on radiological protection (icrp) reference phantoms can provide a more realistic view of the human anatomy in comparison with the previously used mathematical p...

Introduction Accurate estimation of the absorbed dose in radiosensitive organs, located away from the target volume during radiotherapy, is one of the main reasons for the development of reference phantoms. The International Commission on Radiological Protection (ICRP) reference phantoms can provide a more realistic view of the human anatomy in comparison with the previously used mathematical p...

The Monte Carlo simulations using the mathematical phantom of a human body model is useful as a method of getting to know the details of the radiation exposure in a human body. However, it is very difficult to evaluate experimentally the validity of the calculation result of the simulation using the human body model. Then, the mathematical phantom of voxel-type (voxel phantom) for the Monte Car...

introduction: ordered subset expectation maximization (osem), is an effective iterative method for spect image reconstruction. the aim of this study is the evaluation of the role of system matrix in osem image reconstruction method using four different physical beam radiation models with three detection configurations. methods: spect was done with an arc of 180 degree in 32 projections after i...

Entrance skin dose (ESD) is an important parameter for assessing the dose received by a patient in a single radiographic exposure. The most useful way to evaluate ESD is either by direct measurement on phantoms using an ionization chamber or using calculations based on a mathematical model. We compared six phantoms (three anthropomorphic, two physical, and one mathematical) in 11 standard clini...

objective: different categories are available for estimating of radiation dose. radioisotopes with the same energy and almost the same physical properties have similar effects. monte carlo technique is a computerized method based on mathematical simulation of physical processes. the main purpose of this study is to show that beta particles are not able to penetrate deep into the water. also dif...

background: photon attenuation as an inevitable physical phenomenon influences on the diagnostic information of spect images and results to errors in accuracy of quantitative measurements. this can be corrected via different physical or mathematical approaches. as the correction equation in mathematical approaches is nonlinear, in this study a new method of linearization called ‘piece wise line...