background: obtaining high quality images in single photon emission tomography (spect) device  is the most important goal in nuclear medicine. because if image quality is low, the possibility of making a mistake in diagnosing and treating the patient will rise. studying effective factors in spatial resolution of imaging systems is thus deemed to be vital. one of the most important factors in sp...

introduction: in single photon emission computed tomography (spect), the projection data used for image reconstruction are distorted by several factors, including attenuation and scattering of gamma rays, collimator structure, data acquisition method, organ motion, and washout of radiopharmaceuticals. all these make reconstruction of a quantitative spect image very difficult. simulation of a sp...

introduction use of hadron therapy as an advanced radiotherapy technique is increasing. in this method, secondary particles are produced through primary beam interactions with the beam-transport system and the patient’s body. in this study, monte carlo simulations were employed to determine the dose of produced secondary particles, particularly neutrons during treatment. materials and methods i...

the monte carlo method can be used to describe any technique that approximates solutions to quantitative problems through statistical sampling. this method is considered to be the most accurate method for dose calculation in radiotherapy. for complete modeling of a linear accelerator, it is required that the manufactured information covers all data, but some data such as primary electron energy...

Introduction: Average glandular dose (AGD), entrance skin air kerma (ESAK) and normalized glandular dose (DgN) are the main dosimetric quantities in mammography. In this study, DgN is evaluated in the presence of breast cyst, which is a common disease among women and the influence of size, number and location of the cysts on the DgN is investigated. Materials and Meth...

Background The objective of this work is to estimate the financial impact of increasing the monitoring period for breast cancer, which is financed by the Sistema de Protección Social en Salud (SPSS-Social Protection System in Health). Methods A micro-simulation model was developed to monitor a cohort of patients with breast cancer, and also an estimation was made on the probability of survivi...

BACKGROUND X-ray mammography is one of the general methods for early detection of breast cancer. Since glandular tissue in the breast is sensitive to radiation and it increases the risk of cancer, the given dose to the patient is very important in mammography. OBJECTIVES The aim of this study was to determine the average absorbed dose of X-ray radiation in the glandular tissue of the breast d...

introduction accurate estimation of the skin-absorbed dose in external radiation therapy is essential to estimating the probability of secondary carcinogenesis induction materials and methods electron contamination in prostate radiotherapy was investigated using the monte carlo (mc) code calculation. in addition, field size dependence of the skin dose was assessed. excess cancer risk induced by...