Cadmium Telluride Gamma Camera

Entine, G.; Luthmann, Robert; Mauderli, Walter; Fitzgerald, Lawrence T.; Williams, Clyde M.; Tosswill, Christopher H.

doi:10.1109/tns.1979.4329689

Cited by 20 publications

(6 citation statements)

References 2 publications

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“…Due to the rotating slat design, only a limited number of detector elements is required to fill a strip area which reduces the cost. A similar design has been published by Entine (Entine et al 1979) about 20 years ago, combining a CdTe detector with a parallel plate collimator. Before this, the design of a linear detector has been proposed independently by Keyes (Keyes 1975) and Tosswill (Tosswill 1977).…”

Section: Introductionmentioning

confidence: 99%

Tomographic image quality of rotating slat versus parallel hole-collimated SPECT

2011

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Abstract. Parallel and converging hole collimators are most frequently used in nuclear medicine. Less common is the use of rotating slat collimators for Single Photon Emission Computed Tomography (SPECT). The higher photon collection efficiency, inherent to the geometry of rotating slat collimators results in much lower noise in the data. However, plane integrals contain spatial information in only one direction, whereas line integrals provide two-dimensional information. It is not a trivial question whether the initial gain in efficiency will compensate for the lower information content in the plane integrals. Therefore, a comparison of the performance of parallel hole and rotating slat collimation is needed. This study compares SPECT with rotating slat and parallel hole collimation in combination with MLEM reconstruction with accurate system modeling and correction for scatter and attenuation. A contrast-to-noise study revealed an improvement of a factor 2 to 3 for hot lesions and more than a factor of 4 for cold lesion. Furthermore, a clinically relevant case of heart lesion detection is simulated for rotating slat and parallel hole collimators. In this case, rotating slat collimators outperform the traditional parallel hole collimators. We conclude that rotating slat collimators are a valuable alternative for parallel hole collimators.

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Section: Introductionmentioning

confidence: 99%

Tomographic image quality of rotating slat versus parallel hole-collimated SPECT

2011

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“…A semiconductor detector containing cadmium telluride (CdTe) or cadmium zinc telluride (CdZnTe) has shown excellent performance and quality for imaging (2)(3)(4)(5)(6)(7). The semiconductor detector is considered to be the most suitable for miniaturization because it does not require the relatively massive photomultiplier tube that characterizes a traditional scintillation/ photomultiplier tube detector.…”

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confidence: 99%

Evaluation of the Efficacy of a Small CdTe γ-Camera for Sentinel Lymph Node Biopsy

Tsuchimochi¹,

Hayama²,

Oda³

et al. 2008

J Nucl Med

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We previously reported the basic performance of a prototype small cadmium telluride (CdTe) g-camera (SSGC) intended for use in radioguided surgeries. In this study, we sought to confirm the favorable previous results and to extend the preliminary findings to examine the efficacy of the SSGC in an animal study and a clinical setting for sentinel lymph node biopsy. Methods: The prototype SSGC (1,024 pixels; field of view, 44.8 · 44.8 mm), equipped with a parallel-hole collimator, was used in both animal and clinical studies. 99m Tc-phytate (18.5 MBq) was injected into the tongues and legs of 6 rabbits. In the clinical study, 74 MBq of 99m Tc-phytate was injected into peritumoral regions in 8 patients with oral cancer. The detection of hot nodes by the SSGC was compared with that by a conventional scintillation g-camera (CGC). Results: The SSGC detected 29 hot nodes in images of 6 rabbits after injection. The number of hot nodes was the same as the number seen in CGC studies, but the CGC required a longer acquisition time to produce comparable images. There were no differences between the SSGC and the CGC in terms of activity ratios and hot node-to-background ratios. The biodistribution of 99m Tc-phytate in removed tissues was evaluated by contact radiography, and radioactivity was assayed with a g-well counter. The mean 6 SD radioactivity in specimens was 0.15% 6 0.15%, with a range of 0.01%-0.62%. In the clinical study, the SSGC detected 30 hot nodes with a 5-to 60-s acquisition time at 4 h after injection. The SSGC documented all hot nodes depicted by the CGC at 4 h after injection. Conclusion: The SSGC showed significant potential for the detection of sentinel lymph nodes in lymphoscintigraphy. The results of the studies suggested that the SSGC facilitates the exploration of hot nodes in sentinel lymph node biopsy.Key Words: lymphoscintigraphy; oncology; semiconductor g-camera; CdTe; handheld g-camera; sentinel lymph node biopsy; radioguided surgery; oral cancer Radi oguided surgery has been accomplished with the use of g-probes, primarily for sentinel lymph node biopsy.However, g-probes can provide only radioactivity counts and variable-pitch audio output based on the intensity of the detected radioactivity. Allowing the surgeon to see the spatial distribution of the increased radioactivity could result in more accurate delineation of the surgical field, thus facilitating the surgery. Therefore, we developed a prototype small semiconductor g-camera (SSGC) that provides images of radioactivities for surgical use (1).For radioguided surgery, the g-camera should be miniaturized or handheld to facilitate its application in the restricted space of a surgical field. A semiconductor detector containing cadmium telluride (CdTe) or cadmium zinc telluride (CdZnTe) has shown excellent performance and quality for imaging (2-7). The semiconductor detector is considered to be the most suitable for miniaturization because it does not require the relatively massive photomultiplier tube that characterizes a traditional scintil...

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“…In the paper by Entine (Entine 1979) there is a very good discussion about the photon flux at the detector of these systems. Previous sensitivity calculations (Webb et al 1993) were done for a systems with a rotating slat collimator on a fixed detector.…”

Section: Introductionmentioning

confidence: 99%

System characteristics of SPECT with a slat collimated strip detector

et al. 2006

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In classical SPECT with parallel hole collimation, the sensitivity is constant over the field of view (FOV). This is no longer the case if a rotating slat collimator with planar photon collection is used: there will be a significant variation of the sensitivity within the FOV. Since not compensating for this inhomogeneous sensitivity distribution would result in non-quantitative images, an accurate knowledge of the sensitivity is mandatory to account for it during reconstruction. On the other hand, the spatial resolution versus distance dependency remains unaltered compared to parallel hole collimation. For deriving the sensitivity, different factors have to be taken into account: a first factor concerns the intrinsic detector properties and will be incorporated into the calculations as a detection efficiency term depending on the incident angle. The calculations are based on a second and more pronounced factor: the collimator and detector geometry. Several assumptions will be made for the calculation of the sensitivity formulae and it will be proven that these calculations deliver a valid prediction of the sensitivity at points far enough from the collimator. To derive a close field model which also accounts for points close to the collimator surface, a modified calculation method is used. After calculating the sensitivity in one plane it is easy to obtain the tomographic sensitivity. This is done by rotating the sensitivity maps for spin and camera rotation. The results derived from the calculations are then compared to simulation results and both show good agreement after including the aforementioned detection efficiency term. The validity of the calculations is also proven by measuring the sensitivity in the FOV of a prototype rotating slat gamma camera. An expression for the resolution of these planar collimation systems is obtained. It is shown that for equal collimator dimensions the same resolution-distance relationship is obtained as for parallel hole collimators. Although, a better spatial resolution can be obtained with our prototype camera due to the smaller pitch of the slats. This can be achieved without a major drop in system sensitivity due to the fact that the slats consist of less collimator material compared to a parallel hole collimator. The accuracy of the calculated resolution is proven by comparison with Monte Carlo simulation and measurement resolution values.

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Cadmium Telluride Gamma Camera

Cited by 20 publications

References 2 publications

Tomographic image quality of rotating slat versus parallel hole-collimated SPECT

Tomographic image quality of rotating slat versus parallel hole-collimated SPECT

Evaluation of the Efficacy of a Small CdTe γ-Camera for Sentinel Lymph Node Biopsy

System characteristics of SPECT with a slat collimated strip detector

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