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Titolo:
Usefulness and pitfalls of planar gamma-scintigraphy for measuring aerosoldeposition in the lungs: A Monte Carlo investigation
Autore:
Lee, ZH; Ljungberg, M; Muzic, RF; Berridge, MS;
Indirizzi:
Case Western Reserve Univ, Univ Hosp Cleveland, Dept Radiol, Nucl Med Div,Cleveland, OH 44106 USA Case Western Reserve Univ Cleveland OH USA 44106 ,Cleveland, OH 44106 USA Univ Lund Hosp, Dept Radiat Phys, Jubileum Inst, S-22185 Lund, Sweden UnivLund Hosp Lund Sweden S-22185 , Jubileum Inst, S-22185 Lund, Sweden
Titolo Testata:
JOURNAL OF NUCLEAR MEDICINE
fascicolo: 7, volume: 42, anno: 2001,
pagine: 1077 - 1083
SICI:
0161-5505(200107)42:7<1077:UAPOPG>2.0.ZU;2-Z
Fonte:
ISI
Lingua:
ENG
Soggetto:
SCATTER CORRECTION; ATTENUATION CORRECTION; SPECT; SIMULATION; IMAGES; QUANTIFICATION; CAMERA; CT;
Keywords:
planar scintigraphy; aerosol lung deposition; scatter; attenuation correction;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
31
Recensione:
Indirizzi per estratti:
Indirizzo: Lee, ZH Case Western Reserve Univ, Univ Hosp Cleveland, Dept Radiol, Nucl Med Div,11100 Euclid Ave, Cleveland, OH 44106 USA Case Western Reserve Univ11100 Euclid Ave Cleveland OH USA 44106
Citazione:
Z.H. Lee et al., "Usefulness and pitfalls of planar gamma-scintigraphy for measuring aerosoldeposition in the lungs: A Monte Carlo investigation", J NUCL MED, 42(7), 2001, pp. 1077-1083

Abstract

Planar gamma -scintigraphy is often used to quantify pulmonary deposition patterns from aerosol inhalers. The results are quite different from those obtained using 5-dimensional PET and SPECT. The purpose of this study was to characterize the effects of scatter and tissue attenuation on the distribution of radiolabeled aerosol as measured by planar scintigraphy using Monte Carlo simulations. This study also investigated the applicability of a few correction methods used in inhalation studies. Methods: Body density mapswere derived from CT scans. Regions of interest-lungs, major airways, and esophagus-were defined from the same CT volume. Two radioactivity source distribution patterns in the lung, uniform and nonuniform, were used. A MonteCarlo program, SIMIND, was used to generate anterior and posterior gamma -images of the composed inhalation distributions for 2 energy windows, photopeak (127-153 keV) and scatter (92-125 keV). The effects of scatter and attenuation were estimated on the basis of the imaging components separated from the simulation. A scatter correction method and 2 attenuation correctionmethods, all applied to inhalation scintigraphy, were evaluated using the simulated images. Results: The amount of scatter ranges from 24% to approximately 29% in the lungs and from 29% to approximately 35% in the central (airway or esophagus) region on the planar images. Significant differences were found among regions and between source distributions (P < 0.05), The fraction k used for dual-energy- based scatter correction also varied and was found to be less than the commonly used k = 0.5, The simplified narrow-beamattenuation correction and the effective (broad-beam) correction methods were found to either under- or overcorrect the regional activities. Conclusion: The amount of scatter and tissue attenuation in the thorax region depends on source distribution and body attenuation. In applying planar scintigraphy for aerosol inhalation studies, it is difficult to obtain precise quantitative measurements because of the uncertainties associated with scatter and attenuation corrections. Accurate corrections require knowledge of bothsource and density distributions.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/09/20 alle ore 13:23:48