X-ray fluorescence computed tomography (XFCT) was performed on a high-intensity synchrotron radiation source or a pencil beam with a long exposure time due to the low emission and detection efficiency of x-ray fluorescence photons. For the first time, the feasibility and experimental results of a full-field fan-beam XFCT with a photon-counting detector array are presented. This full-field fan-b...

Objective(s): The purpose of this study was to examine the optimal reconstruction parameters for brain dopamine transporter SPECT images obtained with a fan beam collimator and compare the results with those obtained by using parallel-hole collimators.Methods: Data acquisition was performed using two SPECT/CT devices, namely a Symbia T6 and an Infinia Hawkeye 4 (device A and B) equipped with fa...

In single photon emission computed tomography (SPECT), a varying-focal-length cone-beam collimator can be used to reduce the truncation problem and to maintain sensitivity when imaging the organ of interest. The collimator is constructed so that the collimator holes focus to a circular symmetric, spatially varying, focal point function. The focal length increases radially from the shortest foca...

Helical tomotherapy (HT) is a novel treatment approach that combines Intensity-Modulate Radiation Therapy (IMRT) delivery with in-built image guidance using megavoltage (MV) CT scanning. The technique utilises a 6 MV linear accelerator mounted on a CT type ring gantry. The beam is collimated to a fan beam, which is intensity modulated using a binary multileaf collimator (MLC). As the patient ad...

  Objective: IQSPECT is an advanced high-speed SPECT modality for performing myocardial perfusion imaging (MPI), which uses a multi-focus fan beam collimator with resolution recovery reconstruction. The aim of this study was to compare IQSPECT compared with conventional SPECT interms of performance based on standard clinical protocols. In addition, we examined the concordance between convention...

In the Beam Delivery Systems (BDS) for linear colliders that have been designed or built, collimators (or scrapers) are used to suppress backgrounds due to the beam halo. Off-energy and off-axis particles are stopped on the collimator jaws, physically limiting the acceptance of the system. This concept does not scale well to higher beam energy, higher intensity or lower emittance. The increased...