Purpose: We had previously shown the MR compatibility of CZT based single photon detectors and associated nuclear data acquisition electronics [1]. The purpose of the present work was to study the feasibility a combined MRSPECT system operating inside a 4T MR system for dual-modality MR-SPECT imaging. The current investigation included a study of the effect of SPECT detector/collimator system o...

The rapid development of the novel gamma-ray detectors and detector clusters based on principles of gammaray tracking opens new broad perspectives to nuclear spectroscopy. An increase of the efficiency and a gain of the Peak/Total [1] alongside with a possibility for an efficient linear polarimetry and imaging are expected to produce a significant impact on future experiments. The HPGe arrays l...

A new gamma camera dedicated to scintimammography (single photon emission mammography—SPEM) now has a full-breast field of view. One can clinically examine a mildly compressed breast with a cranio-caudal-like projection as one would in X-ray mammography. This camera is based on pixelated scintillation arrays and position sensitive photomultiplier tubes. By reducing the collimator-tumor distance...

A pixel-segmented ionization chamber has been designed and built by Torino University and INFN. The detector features a 24 x 24 cm2 active area divided in 1024 independent cylindrical ionization chambers and can be read out in 500 micros without introducing dead time; the digital charge quantum can be adjusted between 100 fC and 800 fC. The sensitive volume of each single ionization chamber is ...

Angulation errors in collimator septa degrade tomographic resolution in SPECT due to mispositioning of events in the projection data. These errors should be small compared to other contributions to SPECT system resolution, such as intrinsic camera and collimator resolution, gantry alignment, and algorithmic smoothing. We describe a radioisotope technique to measure septal angulation errors over...

UNLABELLED Our objective was to optimize the quality of (123)I-metaiodobenzylguanidine (MIBG) scans by using a medium-energy collimator to reduce high-energy-photon septal penetration. METHODS In addition to the 159-keV γ-ray, (123)I has a small abundance of energies above 400 keV that can compromise the image quality of MIBG studies because of septal penetration. Using a low-energy ultrahigh...

PURPOSE The purpose of the study is to investigate the characteristics of a two-dimensional (2D) liquid-filled ion chamber detector array, which is used for the verification of radiotherapy treatment plans that use small field sizes of up to 10 × 10 cm. METHODS The device used in this study was Octavius 1000 SRS model (PTW, Freiburg, Germany). Its 2D array of detectors consists of 977 liquid-...

Prolonged treatment execution time is a concern in CyberKnife robotic radiosurgery. Beam reduction and node reduction technique, and monitor unit optimization methods are adopted to reduce the treatment time. Usage of single collimator in the CyberKnife treatment plan can potentially reduce collimator exchange time. An optimal single collimator, which yields an acceptable dose distribution alon...

PURPOSE There are two collimation systems associated with the CyberKnife system, the fixed cone collimator and the Iris collimator. The Iris collimator is used more frequently because of its superior flexibility. However, sometimes treatments have to be canceled or postponed due to Iris collimator mechanical failures. The purpose of this study is to investigate the feasibility of switching coll...