A5003139265- Medical Imaging Techniques and Applications
- Radiation Detection and Scintillator Technologies
- Advanced Radiotherapy Techniques
- Radiopharmaceutical Chemistry and Applications
- Radiation Therapy and Dosimetry
- Radiomics and Machine Learning in Medical Imaging
- Lung Cancer Diagnosis and Treatment
- Nuclear Physics and Applications
- Advanced X-ray and CT Imaging
- Advanced MRI Techniques and Applications
- Effects of Radiation Exposure
- Advanced X-ray Imaging Techniques
- Radiation Dose and Imaging
- Neuroendocrine Tumor Research Advances
- Radioactive Decay and Measurement Techniques
- Pancreatic and Hepatic Oncology Research
- Atomic and Subatomic Physics Research
- Tracheal and airway disorders
- Cancer Genomics and Diagnostics
- Nonmelanoma Skin Cancer Studies
- Pancreatitis Pathology and Treatment
- Glioma Diagnosis and Treatment
- Management of metastatic bone disease
- Ultrasound and Hyperthermia Applications
- Neuroblastoma Research and Treatments
University of Maryland, Baltimore
2019-2024
Hospital Universitario HM Sanchinarro
2017-2023
Johns Hopkins University
2015-2017
Instituto de Estructura de la Materia
2009-2016
Consejo Superior de Investigaciones Científicas
2009-2016
Universidad Complutense de Madrid
2007-2016
National Institute of Biomedical Imaging and Bioengineering
2016
National Institutes of Health
2016
The University of Texas Southwestern Medical Center
2016
Advanced Imaging Research (United States)
2016
The National Electrical Manufacturers Association (NEMA) standard NU 4-2008 for performance measurements of small-animal tomographs was recently published. Before this standard, there were no testing procedures preclinical PET systems, and manufacturers could not provide clear specifications similar to those available clinical systems under NEMA 2-1994 2-2001. Consequently, evaluation papers used methods that modified ad hoc from the thus making comparisons between difficult. <b>Methods:</b>...
Monte Carlo simulations play an important role in positron emission tomography (PET) imaging, as essential tool for the research and development of new scanners advanced image reconstruction.PeneloPET, a PET-dedicated tool, is presented validated this work.PeneloPET based on PENELOPE, code simulation transport matter electrons, positrons photons, with energies from few hundred eV to 1 GeV.PENELOPE robust, fast very accurate, but it may be unfriendly people not acquainted FORTRAN programming...
Although current PET scanners are designed and optimized to detect double coincidence events, there is a significant amount of triple coincidences in any acquisition. Triple may arise from causes such as: inter-detector scatter (IDS), random interactions (RT), or the detection prompt gamma rays with annihilation photons when non-pure positron-emitting radionuclides used (β(+)γ events). Depending on data acquisition settings scanner, these events discarded processed as set if energy three...
We aimed to determine the consistency of quantitative PET measurements metabolic tumor volume (MTV) and intratumoral heterogeneity index for primary untreated pancreatic adenocarcinomas, when using dual-time point F-FDG PET/CT imaging.This is an institutional review board-approved, retrospective study including 71 patients with adenocarcinoma, who underwent imaging, at approximately 1 hour (early) 2 hours (delayed), after injection. Automated gradient-based 50% SUVmax-threshold segmentation...
Small animal PET systems based on rotating planar detectors posses some interesting advantages for high sensitivity, resolution imaging. We have designed the rPET MLS crystals assembled a 30/spl times/30 matrix optically coupled to flat-panel PS-PMT. Weighted position readout circuits pre-process 64 signals from 8/spl times/8 anodes matrix, which are digitized using charge-integrating converter. The amplification electronics, including trigger output coincidence detection, and voltage supply...
The multi-pixel photon counter (MPPC) or silicon photo-multiplier (SiPM), recently introduced as a solid-state photodetector, consists of an array Geiger-mode photodiodes (microcells). It is promising device for PET thanks to its potential high detection efficiency (PDE) and immunity magnetic fields. also very easy use, with simple electronic read-out, gain small size. In this work we evaluate the performance three 1 × mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...
We investigated the feasibility of using simpler methods than manual whole-organ volume-of-interest (VOI) definition to estimate organ activity concentration in single photon emission computed tomography (SPECT) cases where can be assumed uniformly distributed on scale voxel size. In particular, we an anatomic region-of-interest (ROI) defined a transaxial slice, and sphere placed inside boundaries.The evaluation was carried out Monte Carlo simulations based patient indium 111 pentetreotide...
Investigations on radiation-induced lung injury (RILI) have predominantly focused local effects, primarily those associated with radiation damage to parenchyma. However, recent studies from our group and others revealed that branching serial structures such as airways vessels may also a substantial impact post-radiotherapy (RT) function. Furthermore, results multiple functional avoidance RT trials, although promising, demonstrated only modest toxicity reduction, likely because they were dose...
Monte Carlo (MC) simulations are widely used in positron emission tomography (PET) for optimizing detector design, acquisition protocols, and evaluating corrections reconstruction methods. PeneloPET is a MC code based on PENELOPE, PET which considers geometry, electronics materials, source definitions. While has been successfully employed validated with small animal scanners, it required proper validation clinical scanners including time-of-flight (TOF) information. For this purpose, we...
Recent changes to the guidelines for screening and early diagnosis of lung cancer have increased interest in preserving post-radiotherapy function. Current investigational approaches are based on spatially mapping functional regions generating regional avoidance plans that preferentially spare highly ventilated/perfused lung. A potentially critical, yet overlooked, aspect is radiation injury peripheral airways, which serve as gas conduits from regions. Dose redistribution solely function may...
Pile-up and dead-time are two main causes of nonlinearity in the response a PET scanner as function activity field view (FOV). For given acquisition system, pile-up effects depend on material size object being imaged distribution inside outside FOV, because these factors change singles-to-coincidences ratio (SCR). Thus, it is difficult to devise an accurate correction that would be valid for any acquisition. In this work, we demonstrate linear relationship between SCR effective dead-time,...
With an increasing emphasis on quantitation of SPECT imaging and its use in dosimetry to guide therapies, it is desirable understand the repeatability normal-organ uptake values (SPECT-UVs). We investigated variability normal abdominal organ repeated <sup>111</sup>In-pentetreotide studies. <b>Methods:</b> Nine patients with multiple SPECT/CT studies for clinical purposes were evaluated. Volumes interest drawn organs applied SPECT-UVs. The those was assessed. <b>Results:</b> average SPECT-UV...
A small animal PET/CT system based on a common rotating gantry is proposed. The PET detection subsystem composed of two detector modules MLS arrays and four flat panel type PS-PMT. CT consists in micro-focus X-ray tube semiconductor detector. Space for opposed detectors the scanner have been allocated same plane such way that trans-axial axial centers are both systems. Shielding elements placed around to avoid cross modality contamination. can rotate 370 degrees provide complete data sets...
We present a method to compensate for missing projection data in positron emission tomography (PET), which may result from gaps between adjacent detectors or malfunctioning detectors. To prevent artifacts the reconstruction when using Fourier rebinning (FORE) analytical algorithms, filling is required. This new approach sinogram interpolation prior based on simple iterative frequency selective signal extrapolation initially proposed and successfully applied error concealment image video...
PENELOPE is a Monte Carlo code that simulates the transport in matter of electrons, positrons and photons with energies from few hundred eV to 1 GeV. It robust, fast very accurate, but it may be unfriendly for people not acquainted FORTRAN programming language. We have developed tookit (`PeneloPET') prepare simulations PET SPECT within PENELOPE. Sophisticated can setup by modifying just simple input files. The output data generated at different levels detail analyzed afterwards preferred...
Most small animal PET scanners are based on arrays of pixelated scintillators crystals. As the read-out individual pixels would be too expensive, identification crystal interaction is usually made by center energy methods for instance Anger logic. This allows a reduction in number signals to acquired, but prevents multi-hit events, that is, events one (or several) photon produces several hits detector, thus blurring correct positioning interaction. Improving pixel pursued this work combining...
<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">68</sup> Ga is one of the non-conventional nuclides that are being used in preclinical imaging. One disadvantage versus xmlns:xlink="http://www.w3.org/1999/xlink">18</sup> F its larger positron range, which deteriorates effective spatial resolution and overall image quality. In this work we present a performance evaluation ARGUS small-animal emission tomography (PET) scanner for two emitters, F....
Technological advances have improved the assembly process of PET detectors, resulting in quite small mechanical tolerances. However, high-spatial-resolution systems, even submillimetric misalignments detectors may lead to a notable degradation image resolution and artifacts. Therefore, exact characterization is critical for optimum reconstruction quality such systems. This subject has been widely studied CT SPECT scanners based on cone beam geometry, but this not case tomographs rotating...
Monte Carlo simulations are widely used in positron emission tomography (PET) for optimizing detector design, acquisition protocols, as well developing and assessing corrections reconstruction methods. PeneloPET is a code PET which considers geometry, electronics materials, source definitions. based on PENELOPE, the simulation of transport matter electrons, positrons photons, with energies up to 1 GeV. In this work we use simulate Biograph TruePoint (B-TP), TrueV (B-TPTV) mCT PET/CT...
PeneloPET is a Monte Carlo application based on PENELOPE. We present here the new features and results of validation tests for version that has been compared against data from real scanners. was built as powerful tool PET simulation, it easy to use, fast very accurate. Recently, many improvements have made in code with incorporation realistic signal processing chain by adding possibility running simulations parallel mode cluster computers. A comparison between obtained two small-animal...
Respiratory motion management techniques in radiotherapy (RT) planning are primarily focused on maintaining tumor target coverage. An inadequately addressed need is accounting for dosimetric estimations smaller serial structures. Accurate dose such structures more sensitive to because respiration can cause them move completely or out of a high dose-gradient field. In this work, we study three strategies (m1–m3) find an accurate method estimate the dosimetry airways. To validate these...