Dynamic Imaging with High Resolution Time-of-Flight PET Camera - TOFPET I

Mullani, Nizar A.; Gaeta, J.M.; Yerian, K.; Wong, Wai-Hoi; Hartz, Ross K.; Philippe, E. A.; Bristow, D.; Gould, K. Lance

doi:10.1109/tns.1984.4333329

Cited by 36 publications

(5 citation statements)

References 13 publications

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“…The subjec ts were tested unde r ba seline cond ition s (eyes open and ears unplugged). The stud ies were don e using the TOFPET instrument (FWHM 1.2 ern) (Mullani et al, 1984). An initial attenuation image was obtained using a ring filled with 68gallium, and a total o f 200 million events were collected.…”

Section: Methodsmentioning

confidence: 99%

Neural Substrates of Violent Behaviour a Preliminary Study with Positron Emission Tomography

Volkow¹,

Tancredi²

1987

Br J Psychiatry

153

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Brain function was evaluated in four psychiatric patients with a history of repetitive purposeless violent behaviour, using EEG, CT scan, and positron emission tomography (PET). Three patients showed spiking activity in left temporal regions, and two showed CT scan abnormalities characterised by generalised cortical atrophy. The PET scans for the four cases showed evidence of blood flow and metabolic abnormalities in the left temporal lobe. Two patients also had derangement in the frontal cortex. The patients showing the largest defects with the PET scans were those whose CT scans were reported as normal. This paper shows the utility of PET in investigating possible brain derangements that could lead to violent behaviour.

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Section: Methodsmentioning

confidence: 99%

Neural Substrates of Violent Behaviour a Preliminary Study with Positron Emission Tomography

Volkow¹,

Tancredi²

1987

Br J Psychiatry

153

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“…Time-of-flight (TOF) positron emission tomography (PET) was first proposed in the 1980s (Ter-Pogossian et al 1982, Gariod et al 1982, Mullani et al 1984, Wong et al 1984, Lewellen et al 1988, Mazoyer et al 1990) to improve the noise characteristics of PET images but fell out of favor because the fast scintillators available had poor conventional imaging performance. In addition, the main applications of PET at the time were for brain and cardiac imaging, which benefited more from the high count-rate capability of the available non-TOF scintillators than from the noise reduction associated with TOF imaging.…”

Section: Introductionmentioning

confidence: 99%

The imaging performance of a LaBr₃-based PET scanner

et al. 2009

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A prototype time-of-flight (TOF) PET scanner based on cerium-doped lanthanum bromide [LaBr 3 (5% Ce)] has been developed. LaBr 3 has high light output, excellent energy resolution, and fast timing properties that have been predicted to lead to good image quality. Intrinsic performance measurements of spatial resolution, sensitivity, and scatter fraction demonstrate good conventional PET performance; the results agree with previous simulation studies. Phantom measurements show the excellent image quality achievable with the prototype system. Phantom measurements and corresponding simulations show a faster and more uniform convergence rate, as well as more uniform quantification, for TOF reconstruction of the data, which have 375-ps intrinsic timing resolution, compared to non-TOF images. Measurements and simulations of a hot and cold sphere phantom show that the 7% energy resolution helps to mitigate residual errors in the scatter estimate because a high energy threshold (>480 keV) can be used to restrict the amount of scatter accepted without a loss of true events. Preliminary results with incorporation of a model of detector blurring in the iterative reconstruction algorithm show improved contrast recovery but also point out the importance of an accurate resolution model of the tails of LaBr 3 's point spread function. The LaBr 3 TOF-PET scanner has demonstrated the impact of superior timing and energy resolutions on image quality.

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“…After obtaining , the fitting processing is employed in LF/MVT to define the parameters of the line, such as slope and intercept. We denote the estimation output from fitting processing are slope and intercept , the mean of the threshold voltages and the threshold-crossing time are and , respectively, then (19) The LF solution can also be rewritten as the form of , where is the vector which contains weights of the th threshold-crossing time as (20). (20) where is the threshold index, .…”

Section: Relation Between Lf Combination and The Qp Constraintmentioning

confidence: 99%

Quadratic Programming Time Pickoff Method for Multivoltage Threshold Digitizer in PET

Deng

Xie

2015

IEEE Trans. Nucl. Sci.

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Multi-voltage threshold (MVT) digitization, which has been implemented in our preclinical scanner-Trans-PET BioCaliBurn, is a low-power sampling solution with a reasonable cost for fast scintillation pulses. This MVT digitizing scheme employs a few comparators with programmable reference voltages for determining the time points when the scintillation pulse crosses the user-defined voltage thresholds. After obtaining the digital time samples, use of various sophisticated linear or nonlinear algorithms to improve the accuracy of timing information becomes possible. In the previous implementation of MVT digitizers, the arrival time of a scintillation pulse was determined by the linear fitting (LF) algorithm, which assumes leading edge as a straight line, and not involves the transition time on the falling edge. It is not unreasonable to expect achieving a better timing resolution in MVT-based PET detectors by the combinatorial optimization of MVT samples both on leading and falling edges. In this paper, a novel method, referred to as quadratic programming (QP) method is therefore proposed to mark the time stamps of sampling event pulses. In this method, the arrival time is directly expressed as a parametric combination of the MVT samples. The parameters in the combination are obtained by the quadratic programming which minimizes variation of timing error. To evaluate the performance of QP/MVT method and other time pickoff methods, we setup two gamma ray detectors using crystal and Hamamatsu R9800 PMT. The scintillation pulses are directly read out by Tektronics DPO 71604 digital storage oscilloscope. CTR of 175 ps was obtained by QP/MVT, and 191 ps by LF/MVT, when four thresholds were employed in each of the two channels. The experimental results indicate the potential advantage of QP/MVT in timing determination. Meanwhile, the assumption of linear leading edge, which is the basis of LF method, was demonstrated to be improper in the data analysis. For QP method, probably of even greater significance is the manner to define the parameters rather than the resulting detector-specified parameters.Index Terms-Coincidence timing resolution, mean square error, multi-voltage threshold digitizer, quadratic programming (QP) time pickoff method.

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Dynamic Imaging with High Resolution Time-of-Flight PET Camera - TOFPET I

Cited by 36 publications

References 13 publications

Neural Substrates of Violent Behaviour a Preliminary Study with Positron Emission Tomography

Neural Substrates of Violent Behaviour a Preliminary Study with Positron Emission Tomography

The imaging performance of a LaBr₃-based PET scanner

Quadratic Programming Time Pickoff Method for Multivoltage Threshold Digitizer in PET

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Dynamic Imaging with High Resolution Time-of-Flight PET Camera - TOFPET I

Cited by 36 publications

References 13 publications

Neural Substrates of Violent Behaviour a Preliminary Study with Positron Emission Tomography

Neural Substrates of Violent Behaviour a Preliminary Study with Positron Emission Tomography

The imaging performance of a LaBr3-based PET scanner

Quadratic Programming Time Pickoff Method for Multivoltage Threshold Digitizer in PET

Contact Info

Product

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The imaging performance of a LaBr₃-based PET scanner