We calibrated a scintillation camera for the counts-to-activity conversion factor, CF, by measuring a phantom consisting of a sphere containing a known 131-I activity placed within an elliptical cylinder. Within a 3D OSEM reconstruction algorithm, we employed a depth-dependent detector-response model based on smooth fits to the pointsource-response function. Using the ultra-high-energy (UHE) co...

Positron Emission Tomography (PET) is a radiotracer imaging technique based on the administration (typically by injection) of compounds labelled with positron emitting radionuclides to a patient under study. When the radio-isotope decays, it emits a positron, which travels a short distance before annihilating with an electron. This annihilation produces two high-energy (511 keV) gamma photons p...

This paper concerns cone-beam tomography from limited data. Cone-beam tomography is a technique used to visualize the interior of a three-dimensional (3-D) object in a non-invasive way. This technique involves two steps. In the first step, measurements called cone-beam projections are taken. In the second step, digital signal processing techniques are used to process the measurements to form a ...

Abstract High-energy, long gamma-ray bursts (GRBs) can be generated by the core collapse of massive stars at end their lives. When they happen in close-by universe exceptionally bright, as seen from Earth case recent, giant, long-lasting GRB221009A. GRB221009A was produced a collapsing star with redshift 0.152: this event observed many space experiments, which also detected an extraordinary aft...

A second generation proton beamwriting line has been installed at the Centre for Ion BeamApplications at the National University of Singapore. This system features a high demagnification lens system based on compact OM52 lenses with reduced working distance. The system can operate in a variety of high demagnification configurations, including the spaced Oxford triplet and the double-crossover R...

The portable germanium detector based HHRIDs are generally intended to be operated in low to medium radiation fields with as much sensitivity as possible. However, in some circumstances the interfering radioactive background may be significant with respect to the source of interest. For example: a shipping container full of NORM may be used in an attempt to mask the presence of a concealed SNM ...

UNLABELLED This study was performed to investigate the usefulness of a general-purpose medium-energy (ME) collimator for the accurate localization of the sentinel lymph node (SLN) in breast cancer patients. METHODS We compared phantom images and lymphoscintigraphy images obtained under different conditions for a patient with breast cancer. Comparisons were performed between 2 cameras, between...

The purpose of this study was to experimentally quantify the change in response of an amorphous silicon (a-Si) electronic portal imaging device (EPID) to dynamic multileaf collimator (dMLC) beams with varying MLC-transmitted dose components and incorporate the response into a commercial treatment planning system (TPS) EPID prediction model. A combination of uniform intensity dMLC beams and stat...

An algorithm for dynamic multileaf-collimator (dMLC) tracking of a target performing a known a priori, rigid-body motion during volumetric modulated arc therapy (VMAT), has been experimentally validated and applied to investigate the potential of the Agility (Elekta AB, Stockholm, Sweden) multileaf-collimator (MLC) for use in motion-compensated VMAT delivery. For five VMAT patients, dosimetric ...

' 'One picture is worth more than a thousand words''. The validity of this expression, which is a leitmotiv in the publicity sector, is not limited to the strategy underlying advertisements. It certainly also applies to the commanding role images play in diagnostic medicine. To draw lines of development in imaging instruments, one must start where the arsenal of nuclear medicine equipment stand...