Fully Three-dimensional Reconstruction For A Pet Camera With Retractable Septa

Townsend, David W.; Geissbühler, Antoine; Defrise, Michel; Hoffman, Edward J.; Spinks, T.J.; Bailey, Dale L.; Gilardi, M.C.; Jones, Terry

doi:10.1109/nssmic.1990.693539

Cited by 21 publications

(18 citation statements)

References 21 publications

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“…It is clear that, while we now have systems with inherently high resolution, we rarely have sufficient sensitivity to realise this. This has been the impetus for the development of fully 3D acquisition and reconstruction strategies in PET [5].…”

Section: Discussionmentioning

confidence: 99%

“…The data are sorted in real-time to give sinograms of dimensions 160 projection elements by 192 radial samples (over 180°). When operating in conventional 2D mode, 31 sinoograms are produced which result in 31 reconstructed planes of slice spacing 3.1 mm; when the septa are retracted (3D mode), 256 sinograms (16 detector elements axially in coincidence with the opposing 16 detector elements) are produced and subsequently reconstructed into 31 planes axially of slice spacing 3.1 mm using a fully three-dimensional algorithm [5]. The advantage of the 3D mode is that it utilises the full sensitivity of the cylindrical detector by accepting all possible coincidence lines of response which are within the acceptance angle of the axial field of view of the scanner (10.8 cm); in 2D mode this is limited to less than 1.3 cm.…”

Section: Description Of the Scannersmentioning

confidence: 99%

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Performance comparison of a state-of-the-art neuro-SPET scanner and a dedicated neuro-PET scanner

Bailey¹,

Zito

Gilardi

et al. 1994

Eur J Nucl Med

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The physical performances of two current state-of-the-art scanners dedicated to functional imaging of the brain, one a single-photon emission tomography (SPET) scanner and the other a positron emission tomography (PET) scanner, have been compared under identical conditions. The aim of the study was to compare the capabilities of the devices under conditions resembling the routine clinical environment, as well as to consider other issues such as radiation burden for some common investigations. Both systems have slightly less than 11-cm axial fields of view. The PET system can be operated in a septa-less (3D) mode as well as conventionally with septa (2D). The spatial resolution of both devices was less than 8 mm in all dimensions in scattering media. On average, the PET scanner's resolution was approximately 10%-15% better than the SPET system. Energy resolution on the SPET system was superior due the scintillator used [NaI(Tl)]. Sensitivity in air with a line source on the PET system was found to be approximately 150 times greater in 3D and approximately 25 times greater in 2D than with the SPET system. A normal subject was studied on each system in an attempt to obtain the highest quality data possible for a subjective comparison. It is clear that, while PET retains the advantages of more desirable radiopharmaceuticals and higher sensitivity, the quality obtainable from SPET devices has improved markedly. SPET may prove as useful for many clinical investigations.

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Section: Discussionmentioning

confidence: 99%

Section: Description Of the Scannersmentioning

confidence: 99%

Performance comparison of a state-of-the-art neuro-SPET scanner and a dedicated neuro-PET scanner

Bailey¹,

Zito

Gilardi

et al. 1994

Eur J Nucl Med

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“…T HREE-DIMENSIONAL (3D) positron emission tomography (3D PET) has been widely applied to molecular imaging and the field of nuclear medicine [1]. This method provides higher detection efficiency than that of 2D PET [2].…”

Section: Introductionmentioning

confidence: 99%

A Hybrid Scatter Correction Method Combining the SSS Algorithm and Beam Stopper Method for 3D PET

Lin

Yao

et al. 2013

IEEE Trans. Nucl. Sci.

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Scattered events represent a major cause of inaccurate quantification and image degradation in three-dimensional (3D) positron emission tomography (3D PET) scanners. The single scatter simulation (SSS) method is the most widely used scatter correction method. However, this method relies on tail data to scale the estimated scatter to the measured data. Consequently, this method might fail when tail data are insufficient; for example, when scanning obese patients. Unfortunately, the global prevalence of obesity has increased substantially in recent decades; hence, developing alternative solutions to this problem is necessary. The beam stopper (BS) method is used to measure the actual scatter at locations blocked by the BS device. This method can then be applied to estimate the entire scatter sinogram by using an interpolation. However, this interpolation might not reflect the true condition if the BS device has been set up inappropriately. This study presents a hybrid scatter correction method (SSS-BS) based on the SSS and BS methods. In the SSS-BS method, the scatters measured by applying the BS method are used to adjust the scatter distribution calculated by employing the SSS method, thereby obtaining a more accurate scatter distribution. The performance of this hybrid method was investigated by using Monte Carlo simulations. A thorax Zubal phantom (55.8 cm in width and 37.8 cm in height) and a Jaszczak-like phantom (55.2 cm in diameter and 22.75 cm in length) were used to investigate cases involving obese patients. In contrast to the SSS method, the hybrid method does not suffer from the scatter-distribution inaccuracies caused by insufficient tails. The results from the Zubal phantom show that the SSS-BS, SSS, and BS methods yield similar scatter-fraction (SF) estimates, whereas the SSS-BS and SSS methods have a slightly smaller root mean square error (RMSE) of reconstructed images than that of the BS method. For the Jaszczak-like phantom, the SSS-BS method generates a more accurate estimate of SF than both the SSS and BS methods do, reducing the RMSE by nearly half. This study demonstrates that the hybrid method enables the accurate scatter-distribution estimation of 3D PET in cases involving obese patients.

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“…For transmission studies, the source is outside the transaxial fieldof-view, close to the detector, and for systems without septa the countrate limitation of the detector is reached with a relatively low intensity source. For this reason, systems with retractable septa [2,3] perform the transmission study with the septa extended, whereas the emission study may bc acquired with the septa retracted. Of the commercial systcms that have been reported on, only the partial ring ART from CTI Medical Systems [4] and full ring QUEST from GE Medical Systems, which is based on the PENN PET design [5], operate full-time without septa.…”

Section: Introductionmentioning

confidence: 99%

Post-injection transmission scans in a PET camera operating without septa with simultaneous measurement of emission activity contamination

Smith¹,

Karp²

1996

IEEE Trans. Nucl. Sci.

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We report here on methods developed to reliably perform attenuation correction by post-injection transmissicln in a volume imaging PET scanner. The method directly measures the emission contamination during the transmission study, using a virtual transmission source position offset by 20' from the actual 68Ge transmission source. Events are recorded only if they meet a co-linearity requirement with either the real or virtual source position. The simultaneous measurements of the emission contamination and transmission data remove the need for complex corrections to the emission data and are not subject to activity redistributions between emission and transmission scans performed sequentially. Correction is necessary, however, for the extra deadtime that vanes with the amount of emission activity in the FOV. The extra deadtime is determined from a lookup table of deadtime as a function of detector countrates, which are recored during the study. The lookup table is based upon phantom measurements. Using patient and phantom data, with both pre-and post-injection transmission measurements, this method is shown to be reliable for attenuation correction in the body. In addition, it enables the calculation of Standardised Uptake Values for analyzing tumor activity.

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Fully Three-dimensional Reconstruction For A Pet Camera With Retractable Septa

Cited by 21 publications

References 21 publications

Performance comparison of a state-of-the-art neuro-SPET scanner and a dedicated neuro-PET scanner

Performance comparison of a state-of-the-art neuro-SPET scanner and a dedicated neuro-PET scanner

A Hybrid Scatter Correction Method Combining the SSS Algorithm and Beam Stopper Method for 3D PET

Post-injection transmission scans in a PET camera operating without septa with simultaneous measurement of emission activity contamination

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