Compton Cameras for Nuclear Medical Imaging

Rogers, W.L.; Clinthorne, N.H.; Bolozdynya, A.

doi:10.1016/b978-012744482-6.50022-3

Cited by 20 publications

(11 citation statements)

References 71 publications

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“…This region takes the shape of a cone that originates at the scatter position in the 1st detector, has its axis aligned with the line connecting the positions in the two detectors [1]. When this cone is backprojected through a slit, the region is effectively reduced to two lines in the plane of the slit.…”

Section: Reconstructionmentioning

confidence: 99%

“…Moreover, as the source energy increases, photons penetrating the collimator create a background problem which has limited the use of conventional SPECT systems for imaging sources with energies much above 250 keY. The Compton SPECT imaging technique removes the inherent coupling between efficiency and resolution found in conventional systems by replacing the mechanical collimator with a position sensitive detector in which the incident photons Compton scatter and continue on to be absorbed by a position sensitive second detector [1]. The source distribution can then be reconstructed from the energies and positions in the two detectors.…”

Section: Introductionmentioning

confidence: 99%

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Performance of Electronically Collimated SPECT Imaging System in the Energy Range from 140 keV to 511 keV

Cochran

Burdette

Chesi

et al. 2008

2008 IEEE Nuclear Science Symposium Conference Record

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Conventional SPECT cameras rely on photonabsorbing collimators to collect spatial information on radioactive source distributions thereby coupling efficiency with spatial resolution in an inverse relationship as well as causing a rapid decrease in performance with increasing incident photon energy. The Compton SPECT imaging technique replaces the conventional collimator with a position sensitive scattering detector, or "electronic" collimator. This decouples the efficiency and spatial resolution of the system and also leads to increased performance for higher energy sources. However, new technical challenges are introduced in the form of high count rates, timing resolution requirements, and complexity in the image reconstruction. A prototype system using pixelated silicon as the position sensitive scattering detector has been built to quantify the benefits realized by a Compton camera for higher energy sources in the range from 99mTc (140 keV) to the positron annihilation energy (511 keV). In order to reduce some of the technical complexities of the conventional Compton camera arrangement, the initial prototype has been configured to effectively limit the image region to a two-dimensional "slice" geometry.

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Section: Reconstructionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Performance of Electronically Collimated SPECT Imaging System in the Energy Range from 140 keV to 511 keV

Cochran

Burdette

Chesi

et al. 2008

2008 IEEE Nuclear Science Symposium Conference Record

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“…The inversion of conical Radon transforms arises in single photon emission tomography (SPECT) using Compton cameras [22,23], as well as in other applications such as single scattering optical tomography [24]. In the context of SPECT with Compton cameras, the general radial weight that we consider in this paper allows to include the physically relevant effect of attenuation of photons.…”

Section: Introductionmentioning

confidence: 99%

Variational regularization of the weighted conical Radon transform

Haltmeier

Schiefeneder

2018

Inverse Problems

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Recovering a function from integrals over conical surfaces recently got significant interest. It is relevant for emission tomography with Compton cameras and other imaging applications. In this paper, we consider the weighted conical Radon transform with vertices on the sphere. Opposed to previous works on conical Radon transform, we allow a general weight depending on the distance of the integration point from the vertex. As first main result, we show uniqueness of inversion for that transform. To stably invert the weighted conical Radon transform, we use general convex variational regularization. We present numerical minimization schemes based on the Chambolle-Pock primal dual algorithm. Within this framework, we compare various regularization terms, including non-negativity constraints, H I -regularization and total variation regularization. Compared to standard quadratic Tikhonov regularization, TV-regularization is demonstrated to significantly increase the reconstruction quality from conical Radon data.

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“…However, it is adequate for very low-energy g-ray and x-ray emitters, such as 125 I, and silicon strip detectors are available with pixel sizes of ,100 mm for ultrahigh-resolution applications. Another application for which silicon strip detectors show promise is Compton g-cameras, where both good spatial resolution and a high likelihood for Compton interactions are very desirable (22).…”

Section: Semiconductorsmentioning

confidence: 99%

Recent Advances in SPECT Imaging

Madsen

2007

Journal of Nuclear Medicine

285

141

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SPECT is a rapidly changing field, and the past several years have produced new developments in both hardware technology and image-processing algorithms. At the component level there have been improvements in scintillators and photon transducers as well as a greater availability of semiconductor technology. These devices permit the fabrication of smaller and more compact systems that can be customized for particular applications. New clinical devices include high-count sensitivity cardiac SPECT systems that do not use conventional collimation and the introduction of diagnostic-quality hybrid SPECT/CT systems. While there has been steady progress with reconstruction algorithms, exciting new processing algorithms have become commercially available that promise to provide substantial reductions in SPECT acquisition time without sacrificing diagnostic quality. Preclinical small-animal SPECT systems have become a major focus in nuclear medicine. These systems have pushed the limits of SPECT into the submillimeter range, making them valuable molecular imaging tools capable of providing information unavailable from other modalities. From the beginning of radionuclide imaging, there has been a dedicated effort to produce tomographic images of the internal distribution of radiopharmaceuticals. Although the early development of SPECT will not be discussed in this article, an excellent review of the key investigators and their ground-breaking work can be found in a recent article by Jaszczak (1). The present article will focus on recent developments in SPECT that cover approximately the past 3 y. I will begin by briefly reviewing the fundamental physical assumptions underlying SPECTand follow that with a discussion of the advances in detection instrumentation. Clinical and research devices designed for patient studies will be reviewed next. Small-animal SPECT systems will also be described. These sections will be followed by a review of reconstruction algorithms and correction methods. An outstanding in-depth source of information on all of these topics for the interested reader can be found in the book Emission Tomography: The Fundamentals of PET and SPECT (2).Conventional nuclear medicine images compress the 3-dimensional (3D) distributions of radiotracers into a 2-dimensional image. As a result, the contrast between areas of interest and the surrounding territory is often significantly reduced. This reduction limits the diagnostic information that is available in the study. In addition, the exact location of an abnormality can be difficult to determine. Tomographic images remove these difficulties but at the price of longer acquisition times, poorer spatial resolution, and the susceptibility to artifacts. Recent advances in SPECT instrumentation and processing have made marked improvements in each of these areas. SPECT FUNDAMENTALSThe fundamental objective of any tomographic imaging is to determine the internal distribution of an object solely from external measurements. This can be accomplished only if the following re...

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Compton Cameras for Nuclear Medical Imaging

Cited by 20 publications

References 71 publications

Performance of Electronically Collimated SPECT Imaging System in the Energy Range from 140 keV to 511 keV

Performance of Electronically Collimated SPECT Imaging System in the Energy Range from 140 keV to 511 keV

Variational regularization of the weighted conical Radon transform

Recent Advances in SPECT Imaging

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