introduction: gamma knife is an instrument specially designed for treating brain disorders. in gamma knife, there are 201 narrow beams of cobalt-60 sources that intersect at an isocenter point to treat brain tumors. the tumor is placed at the isocenter and is treated by the emitted gamma rays. therefore, there is a high dose at this point and a low dose is delivered to the normal tissue surroun...

Introduction: Nasopharyngeal carcinoma is one of the most common malignancies in the head and neck region and radiotherapy is its treatment of choice. In spite of the fact that it is widely used, due to the presence of many sensitive organs or tissues in this region, patients may suffer from a wide range of side effects. One such sensitive tissue is the spinal cord. If the absorbed dose to spin...

The authors attempt to establish the relative biological effectiveness (RBE) calculation for designing therapeutic proton beams on the basis of microdosimetry. The tissue-equivalent proportional counter (TEPC) was used to measure microdosimetric lineal energy spectra for proton beams at various depths in a water phantom. An RBE-weighted absorbed dose is defined as an absorbed dose multiplied by...

introduction gallium-67 (67ga) has been used as a radionuclide for imaging a variety of solid tumors since 1969. since then use of various gallium-based radiotracers has been reported. recently, 67ga-labeled acetylacetate bis(thiosemicarbazones) (67ga-aats) complex with significant tumor accumulation and fast blood clearance has been employed. materials and methods in this study, the absorbed d...

Introduction: Gamma Knife is an instrument specially designed for treating brain disorders. In Gamma Knife, there are 201 narrow beams of cobalt-60 sources that intersect at an isocenter point to treat brain tumors. The tumor is placed at the isocenter and is treated by the emitted gamma rays. Therefore, there is a high dose at this point and a low dose is delivered to the normal tissue surroun...

Background: The success of radiation therapy depends on accurate dose delivery to the target. Diode in vivo measurement of entrance and exit dose is a valuable quality assurance (QA) tool to ensure accurate dose delivery.  Materials and Methods: This study was performed at BINO Cancer Hospital, Bahawalpur. Entrance and exit dose measurements were done with p-type diode for various types of canc...

An early diagnosis of bone metastasis is very important for making a right decision on a subsequent therapy. One of the most important steps to be taken initially, for developing a new radiopharmaceutical is the measurement of organ radiation exposure dose. In this study, the dosimetric studies of a novel agent for SPECT-imaging of the bone metastasis, 111In-(4{[(bis(phosphonomethyl))carbamoyl]...