Performance Evaluation of a Dedicated Camera Suitable for Dynamic Radiopharmaceuticals Evaluation in Small Animals

Loudos, George; Majewski, S.; Wojcik, R.; Weisenberger, A.G.; Sakellios, N.; Nikita, Konstantina S.; Uzunoglu, N.K.; Bouziotis, Penelope; Xanthopoulos, Stavros; Varvarigou, Alexandra D.

doi:10.1109/tns.2007.896212

Cited by 34 publications

(19 citation statements)

References 24 publications

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“…Before starting, the code was validated through comparison with some experimental measurements. Figure 1 shows the code validation by comparison of our results and the results of spatial resolution in the study by Loudos and et al (17).…”

Section: Simulation Set-upmentioning

confidence: 86%

Effects of Crystal Pixel Size and Collimator Geometry on the Performance of a Pixelated Crystal -Camera Using Monte Carlo Simulation

Rasouli

Takavar²,

Ay³

et al. 2010

Journal of Nuclear Medicine Technology

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Dedicated g-cameras based on pixelated scintillators have long been used for breast tumor imaging. Intercrystal scattering (ICS) increases the background counting rate and degrades the image quality when small crystal pixels are used. Because of the small size of applied collimators, scattered radiation and septal penetration are high, and therefore collimator characteristics must be carefully considered. In our study, we investigated the influence of ICS events on position-detection accuracy (PDA) for pixelated crystals and the effects of different geometries of hexagonal-hole collimators on the performance of these cameras, using Monte Carlo simulation to optimize camera design. The arrays of thallium-doped cesium iodide detectors with different pixel dimensions that had been exposed to 140-keV photons of isotropic point source, 50 mm from the collimator surface, were simulated. Hexagonal-hole collimators were 10.5, 15, and 21 mm long. The septal thickness varied from 0.1 to 0.5 mm, with 3 different hole diameters. The results confirmed that by increasing the crystal pixel size, ICS was decreased and change of detection efficiency was negligible, but PDA, contrast-to-noise ratio, and spatial resolution (full width at half maximum) were increased. Our experiences confirmed that 2 · 2 mm was an optimum crystal pixel size, especially for a lower ICS fraction and an appropriate full width at half maximum. Because collimators are the limiting factor for spatial resolution and sensitivity, careful collimator design is of great importance.Key Words: pixelated g-camera; PDA; DE; ICS; CNR Nucl Med Technol 2010; 38:199-204 DOI: 10.2967/jnmt.109.073072 St andard g-cameras traditionally have been used to diagnose a major health problem for women-that is, breast carcinoma. System limits are essentially related to the spatial resolution of these standard g-cameras, prompting a need for researchers to build dedicated high-resolution g-cameras. The pixelated crystal, in comparison to continuous crystals, limits the degree to which the scintillation light spreads laterally and thereby can improve spatial resolution. Of course, such a design improves spatial resolution at the expense of a deterioration of the energy resolution resulting from light losses in the pixelated crystal, compared with that of a single, continuous crystal. However, the arrays of solid-state detectors, such as cadmium-zinc-telluride, provide a promising alternative technology as a compact high-resolution g-camera, with the advantage of improved energy resolution, compared with the resolution of pixilated scintillators. Many workers up to now have performed simulations and measurements to improve the performance of these cameras for detecting T1a tumors (size, ,5 mm) (1-7). Monte Carlo (MC) simulation techniques are useful when experimental measurements are not practical or experiments are too expensive. In an ideal environment, the parameters affecting the performance of an imaging system, such as collimator configuration and detector pixel size, are...

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Section: Simulation Set-upmentioning

confidence: 86%

Effects of Crystal Pixel Size and Collimator Geometry on the Performance of a Pixelated Crystal -Camera Using Monte Carlo Simulation

Rasouli

Takavar²,

Ay³

et al. 2010

Journal of Nuclear Medicine Technology

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“…50 The detection device is based on two Position Sensitive Photomultiplier Tubes (H85000; Hamamatsu), a parallel hole collimator, and a NaI(Tl) pixelated scintillator. The spatial resolution of the systems is *1.5 mm at 0 mm distance from the collimator's surface.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of α_νβ₃-Mediated Tumor Expression with a ^99mTc-Labeled Ornithine-Modified RGD Derivative During Glioblastoma Growth In Vivo

Tsiapa

Loudos

Fragogeorgi

et al. 2014

Cancer Biotherapy and Radiopharmaceuticals

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In this study, a novel way of distinguishing the intrinsic relationship between a m b 3 integrin targeting and detection of tumor growth by using a radiolabeled tracer based on a cyclic Arg-Gly-Asp (RGD) peptide was provided. The potential of the in vivo scintigraphic imaging of the developing vasculature from the early stage of tumor growth was evaluated. Alongside with the scintigraphic images, biodistribution studies were performed at distinct time points to validate this noninvasive imaging approach. The ability to noninvasively assess the tumor growth of a m b 3 integrin-positive glioblastoma tumors provides a method to better understand tumor angiogenesis in vivo and allows for a direct assessment of anti-integrin treatment efficacy.

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“…34 Here, we report a proof of concept experiment in which hyperthermic treatment was used in vivo in a mouse model of A431 epidermoid carcinoma, which is the third most common type of skin cancer. 36,37 …”

Section: Introductionmentioning

confidence: 99%

In vivo anticancer evaluation of the hyperthermic efficacy of anti-human epidermal growth factor receptor-targeted PEG-based nanocarrier containing magnetic nanoparticles

Baldi¹,

Ravagli²,

Mazzantini³

et al. 2014

IJN

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Polymeric nanoparticles with targeting moieties containing magnetic nanoparticles as theranostic agents have considerable potential for the treatment of cancer. Here we report the chemical synthesis and characterization of a poly(D,L-lactide- co -glycolide)- b -poly(ethylene glycol)-based nanocarrier containing iron oxide nanoparticles and human epithelial growth factor receptor on the outer shell. The nanocarrier was also radiolabeled with 99m Tc and tested as a theranostic nanomedicine, ie, it was investigated for both its diagnostic ability in vivo and its therapeutic hyperthermic effects in a standard A431 human tumor cell line. Following radiolabeling with 99m Tc, the biodistribution and therapeutic hyperthermic effects of the nanosystem were studied noninvasively in vivo in tumor-bearing mice. A substantial decrease in tumor size correlated with an increase in both nanoparticle concentration and local temperature was achieved, confirming the possibility of using this multifunctional nanosystem as a therapeutic tool for epidermoid carcinoma.

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Performance Evaluation of a Dedicated Camera Suitable for Dynamic Radiopharmaceuticals Evaluation in Small Animals

Cited by 34 publications

References 24 publications

Effects of Crystal Pixel Size and Collimator Geometry on the Performance of a Pixelated Crystal -Camera Using Monte Carlo Simulation

Effects of Crystal Pixel Size and Collimator Geometry on the Performance of a Pixelated Crystal -Camera Using Monte Carlo Simulation

Evaluation of α_νβ₃-Mediated Tumor Expression with a ^99mTc-Labeled Ornithine-Modified RGD Derivative During Glioblastoma Growth In Vivo

In vivo anticancer evaluation of the hyperthermic efficacy of anti-human epidermal growth factor receptor-targeted PEG-based nanocarrier containing magnetic nanoparticles

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Performance Evaluation of a Dedicated Camera Suitable for Dynamic Radiopharmaceuticals Evaluation in Small Animals

Cited by 34 publications

References 24 publications

Effects of Crystal Pixel Size and Collimator Geometry on the Performance of a Pixelated Crystal -Camera Using Monte Carlo Simulation

Effects of Crystal Pixel Size and Collimator Geometry on the Performance of a Pixelated Crystal -Camera Using Monte Carlo Simulation

Evaluation of ανβ3-Mediated Tumor Expression with a 99mTc-Labeled Ornithine-Modified RGD Derivative During Glioblastoma Growth In Vivo

In vivo anticancer evaluation of the hyperthermic efficacy of anti-human epidermal growth factor receptor-targeted PEG-based nanocarrier containing magnetic nanoparticles

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Product

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Evaluation of α_νβ₃-Mediated Tumor Expression with a ^99mTc-Labeled Ornithine-Modified RGD Derivative During Glioblastoma Growth In Vivo