Recent technological advances enable radiation therapy to be delivered in a highly conformal manner to targets located almost anywhere in the body. This capability has renewed the clinical interest in hypofractionation wherein the tumor is delivered a few fractions of very large dose per fraction. Extrapolating clinical experience from conventional regimens to fractions of high dose is importan...

Obtaining a good similarity matrix is extremely important in subspace clustering. Current state-of-the-art methods learn the through self-expressive strategy. However, these directly adopt original samples as set of basis to represent itself linearly. It difficult accurately describe linear relation between real-world applications, and thus hard find an ideal matrix. To better samples, we prese...

Currently, a linear no-threshold model is used to estimate health risks associated with exposure to low-dose radiation, a prevalent exposure in the general population, because the direct estimation from epidemiological studies suffers from uncertainty. This model has been criticized based on unique biology of low-dose radiation. Whether the departure from linearity is toward increased or decrea...

background: to investigate the status of the nuclear medicine (nm) centers in iran for the performance of dose calibrators, 18 out of 54 centers providing nm services in iran were randomly selected and inspected in 1997. in the first phase of the study the selected centers were inspected for performing of quality control (qc) tests of dose calibrators. the linearity of the activity response, pr...