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001-es BibID:BIBFORM019243
Első szerző:Buchert, Ralph
Cím:Limitations of bi-linear regression analysis for the determination of receptor occupancy with positron emission tomography / Buchert Ralph, Varga József, Mester János
Dátum:2004
ISSN:0143-3636
Megjegyzések:Linear/multilinear regression methods are widely used in quantitative neuroreceptor positron emission tomography. A reference tissue method based on a bi-linear operational equation, the bi-linear reference tissue method, has been introduced in order to overcome the need for arterial blood sampling. The aim of the present paper was to investigate the sensitivity of the bi-linear reference tissue method to statistical noise, with special regard to the assessment of receptor occupancy. In addition, improvement of the bi-linear reference tissue method by regularization using physiological constraints was evaluated. METHODS: Application of the bi-linear method to dynamic positron emission tomography using the serotonin transporter ligand C-(+)McN5652 was considered. Investigations were performed by computer simulations and analysis of 29 patient studies. RESULTS: The equilibrium specific-to-non-specific partition coefficient V"3 was significantly underestimated by the bi-linear reference tissue method. At realistic noise levels the extent of the underestimation ranged from 25% to 75% for partition coefficients ranging from 0.3 to 0.3, respectively. This caused a 15-60% underestimation of changes in receptor occupancy after simulated intervention. The noise dependence of the bias was confirmed in the patient studies. Regularization significantly reduced the underestimation of the occupancy. CONCLUSIONS: When receptor status or noise level vary substantially, as in receptor occupancy studies, the bias of the bi-linear reference tissue method should be taken into account.
Tárgyszavak:Orvostudományok Klinikai orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Nuclear Medicine Communications. - 25 : 5 (2004), p. 451-459. -
További szerzők:Varga József (1955-) (fizikus) Mester János
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001-es BibID:BIBFORM102721
035-os BibID:(Scopus)85137125116
Első szerző:Képes Zita (orvos)
Cím:Initial clinical experience with dedicated multi-pinhole (MPH) collimator for 99mTc-HMPAO brain perfusion SPECT / Zita Képes, Kornél Kukuts, Attila Oszlánszki, Iván Mihovk, Áron Krizsán, Sándor Barna, Andrew Robinson, Daniel Deidda, János Mester, József Varga, Ildikó Garai, Attila Forgács
Dátum:2022
ISSN:1790-5427
Megjegyzések:Abstract Objective: Dedicated multi-pinhole (MPH) collimators have been successfully tested in selected clinical investigations. The aim of our work was to report initial experiences with an MPH collimator set designed for brain perfusion single photon emission tomography (SPECT). Methods: Ten patients underwent sequential technetium-99m-hexamethylpropyleneamineoxime (99mTc-HMPAO) SPECT with a dual-head SPECT camera equipped with conventional low-energy parallel hole collimators (LEHR), and with a triple-head system equipped with MPH collimators. Low-energy parallel hole collimators data were reconstructed by filtered back projection (FBP), ordered subset expectation maximization (OSEM), software for tomographic image reconstruction (STIR). In addition, both the parallel hole data and MPH data were reconstructed by Tera-TomoTM 3D iterative reconstruction denoted LEHR_TT3D and MPH_TT3D, respectively. Five medical experts visually compared the reconstructed images of the five data sets and defined a ranking sequence from the lowest (1) to the highest (5) image quality. Results were compared using the Friedman test. P values below 0.05 were considered significant. Results: Low-energy parallel hole collimators acquisition resulted in 5 million, while MPH acquisition in 13 million total counts with 30 and 34 minutes of acquisition time, respectively. Mean rank coefficients of the reconstruction methods were 1.96?0.52, 2.66?0.46, 2.86?0.60, 3.62?0.55, 3.9?0.68 for FBP, STIR, LEHR_TT3D, LEHR_OSEM, MPH_TT3D respectively. The differences between MPH_TT3D-FBP (P<0.01); MPH_TT3D-STIR (P<0.05); LEHR_OSEM-FBP (P<0.01) were significant. Conclusion: Image quality provided by MPH collimator is comparable to that provided by conventional LEHR imaging. Higher sensitivity has the potential to shorten acquisition time or to reduce the amount of administered activity.
Tárgyszavak:Orvostudományok Klinikai orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Brain perfusion
SPECT
Multi-pinhole collimator
Reconstruction
Image quality
Megjelenés:Hellenic Journal of Nuclear Medicine. - 25 : 2 (2022), p. 143-147. -
További szerzők:Kukuts Kornél Oszlánszki Attila Mihovk Iván Krizsán Áron Krisztián (1986-) (fizikus) Barna Sándor (1982-) (kutató orvos) Robinson, Andrew Deidda, Daniel Mester János Varga József (1955-) (fizikus) Garai Ildikó (1966-) (radiológus) Forgács Attila (1985-) (fizikus)
Pályázati támogatás:National Grant No. GINOP-2.1.1-15-2015-00609
GINOP
UK National Physical Laboratory through the National Measurement System
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