Single Photon Emission Computed Tomography Radiotracers Research Articles

FlipADAM: a potential new SPECT imaging agent for the serotonin transporter

Single photon emission computed tomography (SPECT) imaging of the serotonin transporter (SERT) in the brain is a useful tool for examining normal physiological functions and disease states involving the serotonergic system. The goal of this study was to develop an improved SPECT radiotracer with faster kinetics than the current leading SPECT tracer, [(123)I]ADAM, for selective SERT imaging. The in vitro binding affinities of (2-(2'-((dimethylamino)methyl)-4'-iodophenylthio)benzenamine) (FlipADAM) (1c), were determined using Hampshire pig kidney cells stably overexpressing the serotonin, norepinephrine (NET) or dopamine transporter (DAT). Localization of [(125)I]FlipADAM (1c) was evaluated through biodistribution and autoradiography in male Sprague Dawley rats, and the specificity of binding was assessed by injecting selective SERT or NET inhibitors prior to [(125)I]FlipADAM (1c). FlipADAM (1c) displayed a high binding affinity for SERT (K(i)=1.0 nM) and good selectivity over NET and DAT binding (43-fold and 257-fold, respectively). [(125)I]FlipADAM (1c) successfully penetrated the blood brain barrier, as evidenced by the brain uptake at 2 min (1.75% dose/g). [(125)I]FlipADAM(1c) also had a good target to non-target (hypothalamus/cerebellum) ratio of 3.35 at 60 min post-injection. In autoradiography studies, [(125)I]FlipADAM (1c) showed selective localization in SERT-rich brain regions such as the thalamic nuclei, amygdala, dorsal raphe nuclei and other areas. [(125)I]FlipADAM (1c) exhibited faster clearance from the brain and time to binding equilibrium when compared to [(125)I]2-(2'-((dimethylamino)methyl)-phenylthio)-5-iodophenylamine [(125)I]ADAM (1b) and a higher target to non-target ratio when compared to [(125)I]5-iodo-2-(2'-((dimethylamino)methyl)-phenylthio)benzyl alcohol [(125)I]IDAM (1a). Therefore, [(123)I]FlipADAM (1c) may be an improved SPECT tracer for imaging SERT.

SPECT imaging in dementia

Single photon emission computed tomography (SPECT) is a non-invasive functional neuroimaging technique that can be used in the diagnosis of dementia. This review describes some of the SPECT radiotracers available for imaging dementia patients and discusses recommendations for the clinical use of this imaging technique.

Molecular cardiovascular imaging

Imaging with radionuclides has historically played an important role in detection of cardiovascular disease as well as in risk stratification and prognostication. With the growth of molecular biology have come new therapeutic interventions and the requirement for new diagnostic imaging approaches. Noninvasive targeted radiotracer-based strategies require the development of new instrumentation to meet these needs. This progress has been made possible with the availability of many technologic advances, which include dedicated micro single-photon emission computed tomography (SPECT) and micro positron emission tomography (PET) hybrid systems for small animal imaging. This review is a brief overview on the subject of molecular imaging. Basic concepts of molecular imaging are reviewed, followed by description of current technologic advances, and current applications to evaluate ischemic heart disease and potential therapeutic intervention. The emphasis is on the use of both SPECT and PET radiotracers, although other imaging modalities are also briefly discussed.

Evaluation of Ultrafiltration for the Free‐Fraction Determination of Single Photon Emission Computed Tomography (SPECT) Radiotracers: β‐CIT, IBF, and Iomazenil

An ultrafiltration system was evaluated for the free‐fraction measurement of SPECT radiotracers (β‐CIT, IBF, and iomazenil) used in functional brain imaging. The effect of temperature, storage, centrifugal force, tracer concentration, and percentage filtered demonstrated a relative error of < 9%. As a result of the minimal temperature effect, 25 °C was employed for all measurements. A comparison of the ultrafiltration system with equilibrium dialysis revealed < 5% difference for β‐CIT and iomazenil, but 16% for IBF. Additionally, the time and ease of operation considerably favored the ultrafiltration system. The precision quantitated by repetition was < 6% for between‐run and within‐run variability. In conclusion, ultrafiltration provided rapid results, demonstrated minor analytical errors, revealed generally good correlation with equilibrium dialysis, and allowed excellent precision.

123I]-2.beta.-carbomethoxy-3.beta.-(4-iodophenyl)tropane: high-affinity SPECT (single photon emission computed tomography) radiotracer of monoamine reuptake sites in brain

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT[123I]-2.beta.-carbomethoxy-3.beta.-(4-iodophenyl)tropane: high-affinity SPECT (single photon emission computed tomography) radiotracer of monoamine reuptake sites in brainJohn L. Neumeyer, Shaoyin Wang, Richard A. Milius, Ronald M. Baldwin, Yolanda Zea-Ponce, Paul B. Hoffer, Elzbieta Sybirska, Mohammed Al-Tikriti, Dennis S. Charney, and Cite this: J. Med. Chem. 1991, 34, 10, 3144–3146Publication Date (Print):October 1, 1991Publication History Published online1 May 2002Published inissue 1 October 1991https://doi.org/10.1021/jm00114a027RIGHTS & PERMISSIONSArticle Views547Altmetric-Citations187LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts