OBJECTIVES Small animal imaging has recently been focused on basic nuclear medicine. We have designed and built a small animal SPECT imaging system using a semiconductor camera and a newly designed collimator. We assess the performance of this system for small object imaging. METHODS We employed an MGC 1500 (Acrorad Co.) camera including a CdTe semiconductor. The pixel size was 1.4 mm/pixel. ...

Introduction: Accurate calculation of equal square field size is important in radiation therapy and A factor, in the Vadash formula must be determine by considering collimator exchange effect. Therefore, the purpose of this study was to determine the best A factor, for calculation of equal square field size in treatment planning   Materials and Methods: A new...

The Leksell Gamma Knife is a standard radiosurgical tool for treating brain lesions by directing beams of gamma radiation to a specific region. The diameter of the gamma beams is confined by collimator systems and available collimator sizes are 4, 8, 14 and 18 mm. The reduction in dose rate for each collimator helmet is called the output factor (OPF). Experimental determination of OPFs is diffi...

This paper presents the first determination of spatial resolution ANET Compact Neutron Collimator, obtained with a measuring campaign at LENA Mark-II TRIGA reactor in Pavia. novel collimator consists sequence collimating and absorbing channels organised chessboard-like geometry. It has scalable structure both length field view. is characterized by an elevated collimation power within limited le...

Intestinal epithelial cells rest on a fibroblast sheath. Thus, factors produced by these fibroblasts may influence epithelial function in a paracrine fashion. We examined modulation of intestinal epithelial function by one such fibroblast product, scatter factor/ hepatocyte growth factor (HGF/SF). This effect was studied in vitro by using model T84 intestinal epithelial cells. When applied to c...

For transmission computed tomography (TCT) systems using a centered transmission source with a fan-beam collimator, the transmission projection data are truncated. To achieve sufficiently large imaging field of view (FOV), we have designed the combination of an asymmetric fan-beam (AsF) collimator and a small uncollimated sheet-source for TCT, and implemented AsF sampling on a two-head SPECT sy...

Background: In myocardial perfusion SPECT imaging, images are degraded by photon attenuation, the distance-dependent collimator, detector response and photons scatter. Filters greatly affect quality of nuclear medicine images Materials and Methods: A phantom simulating heart left ventricle was built. About 1mCi of 99mTc was injected into the phantom. Images were taken from this phantom. Some fi...

In therapy imaging there is a need to optimize imaging protocols and different correction methods for e.g. photon attenuation, contribution from scatter and other physicsrelated effects that limits the possibility to achieve accurate quantitative results. Physical phantom studies are important but lack flexibility and are often difficult to make patient realistic. A complement is to simulate th...

Introduction: Scattered photon is one of the main defects that degrade the quality and quantitative accuracy of nuclear medicine images. Accurate estimation of scatter in projection data of SPECT is computationally extremely demanding for activity distribution in uniform and non-uniform dense media. Methods: The objective of this paper is to develop and validate a scatter correction technique ...