Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, regional chemical composition, and absorption. Different tracers are used for various imaging purposes, depending on the target process within the body. For example, 18F-FDG is commonly used to detect cancer, NaF-F18 is widely used for detecting bone formation, and oxygen-15 is sometimes used to measure blood flow.
Adrenocortical carcinoma (ACC) is an aggressive cancer originating in the cortex of the adrenal gland.
A bone scan or bone scintigraphy is a nuclear medicine imaging technique of the bone. It can help diagnose a number of bone conditions, including cancer of the bone or metastasis, location of bone inflammation and fractures, and bone infection (osteomyelitis).
A gallium scan is a type of nuclear medicine test that uses either a gallium-67 (67Ga) or gallium-68 (68Ga) radiopharmaceutical to obtain images of a specific type of tissue, or disease state of tissue. Gallium salts like gallium citrate and gallium nitrate may be used. The form of salt is not important, since it is the freely dissolved gallium ion Ga3+ which is active. Both 67Ga and 68Ga salts have similar uptake mechanisms. Gallium can also be used in other forms, for example 68Ga-PSMA is used for cancer imaging. The gamma emission of gallium 67 is imaged by a gamma camera, while the positron emission of gallium 68 is imaged by positron emission tomography (PET).
A ventilation/perfusion lung scan, also called a V/Q lung scan, is a type of medical imaging using scintigraphy and medical isotopes to evaluate the circulation of air and blood within a patient's lungs, in order to determine the ventilation/perfusion ratio. The ventilation part of the test looks at the ability of air to reach all parts of the lungs, while the perfusion part evaluates how well blood circulates within the lungs. As Q in physiology is the letter used to describe bloodflow the term V/Q scan emerged.
DASB, also known as 3-amino-4-(2-dimethylaminomethylphenylsulfanyl)-benzonitrile, is a compound that binds to the serotonin transporter. Labeled with carbon-11 — a radioactive isotope — it has been used as a radioligand in neuroimaging with positron emission tomography (PET) since around year 2000. In this context it is regarded as one of the superior radioligands for PET study of the serotonin transporter in the brain, since it has high selectivity for the serotonin transporter.
WAY-100635 is a piperazine drug and research chemical widely used in scientific studies. It was originally believed to act as a selective 5-HT1A receptor antagonist, but subsequent research showed that it also acts as potent full agonist at the D4 receptor. It is sometimes referred to as a silent antagonist at the former receptor. It is closely related to WAY-100135.
Altropane, is a phenyltropane derivative which acts as a potent dopamine reuptake inhibitor and long-acting stimulant drug. It has mainly been used as the 125I radiolabelled form for mapping the distribution of dopamine transporters in the brain, and consequently this has led to its development as a potential diagnostic tool for early detection of Parkinson's disease. It is also being investigated for potential use in the diagnosis and treatment of attention deficit hyperactivity disorder (ADHD).
25B-NBOMe is a derivative of the phenethylamine psychedelic 2C-B, discovered in 2004 by Ralf Heim at the Free University of Berlin. It acts as a potent full agonist for the 5HT2A receptor. Anecdotal reports from users suggest 25B-NBOMe to be an active hallucinogen at a dose of as little as 250–500 µg, making it a similar potency to other phenethylamine derived hallucinogens such as Bromo-DragonFLY. Duration of effects lasts about 12–16 hours, although the parent compound is rapidly cleared from the blood when used in the radiolabeled form in tracer doses. Recently, Custodio et. al (2019) evaluated the potential involvement of dysregulated dopaminergic system, neuroadaption, and brain wave changes which may contribute to the rewarding and reinforcing properties of 25B-NBOMe in rodents.
Positron emission tomography–magnetic resonance imaging (PET–MRI) is a hybrid imaging technology that incorporates magnetic resonance imaging (MRI) soft tissue morphological imaging and positron emission tomography (PET) functional imaging.
Positron emission mammography (PEM) is a nuclear medicine imaging modality used to detect or characterise breast cancer. Mammography typically refers to x-ray imaging of the breast, while PEM uses an injected positron emitting isotope and a dedicated scanner to locate breast tumors. Scintimammography is another nuclear medicine breast imaging technique, however it is performed using a gamma camera. Breasts can be imaged on standard whole-body PET scanners, however dedicated PEM scanners offer advantages including improved resolution.
Iomazenil is an antagonist and partial inverse agonist of benzodiazepine and a potential treatment for alcohol abuse. The compound was introduced in 1989 by pharmaceutical company Hoffmann-La Roche as an Iodine-123-labelled SPECT tracer for imaging benzodiazepine receptors in the brain. Iomazenil is an analogue of flumazenil (Ro15-1788).
Florbetaben, a fluorine-18 (18F)-labeled stilbene derivative, trade name NeuraCeq , is a diagnostic radiotracer developed for routine clinical application to visualize β-amyloid plaques in the brain. It is indicated for Positron Emission Tomography (PET) imaging of β-amyloid neuritic plaque density in the brains of adult patients with cognitive impairment who are being evaluated for Alzheimer's disease (AD) and other causes of cognitive impairment. β-amyloid is a key neuropathological hallmark of AD, so markers of β-amyloid plaque accumulation in the brain are useful in distinguishing AD from other causes of dementia. The tracer successfully completed a global multicenter phase 0–III development program and obtained approval in Europe, US and South Korea in 2014.
Nifene is a high affinity, selective nicotinic α4β2* receptor partial agonist used in medical research for nicotinic acetylcholine receptors, usually in the form of nifene (18F) as a positron emission tomography (PET) radiotracer.
25B-NBOH is a derivative of the phenethylamine derived hallucinogen 2C-B which has been sold as a designer drug. It acts as a potent serotonin receptor agonist with similar affinity to the better-known compound 25B-NBOMe at 5-HT2A and 5-HT2C receptors with pKis values of 8.3 and 9.4, respectively.
Dihydrotetrabenazine or DTBZ is an organic compound with the chemical formula C19H29NO3. It is a close analog of tetrabenazine. DTBZ and its derivatives, when labeled with positron emitting isotopes such as carbon-11 and fluorine-18, are used as PET radioligands for examining VMAT2.
Sandip Basu is an Indian physician of Nuclear Medicine and the Head, Nuclear Medicine Academic Program at the Radiation Medicine Centre. He is also the Dean-Academic (Health-Sciences), BARC at Homi Bhabha National Institute and is known for his services and research in Nuclear Medicine, particularly on Positron emission tomography diagnostics and Targeted Radionuclide Therapy in Cancer. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards for his contributions to Nuclear Medicine in 2012.
Carbon-11 choline is the basis of medical imaging technologies. Because of its involvement in biologic processes, choline is related to diseases, leading to the development of medical imaging techniques to monitor its concentration. When radiolabeled with 11CH3, choline is a useful a tracer in PET imaging. Carbon-11 is radioactive with a half-life of 20.38 minutes. By monitoring the gamma radiation resulting from the decay of carbon-11, the uptake, distribution, and retention of carbon-11 choline can be monitored.
Arterial input function (AIF), also known as a plasma input function, refers to the concentration of tracer in blood-plasma in an artery measured over time. The oldest record on PubMed shows that AIF was used by Harvey et al. in 1962 to measure the exchange of materials between red blood cells and blood plasma, and by other researchers in 1983 for positron emission tomography (PET) studies. Nowadays, kinetic analysis is performed in various medical imaging techniques, which requires an AIF as one of the inputs to the mathematical model, for example, in dynamic PET imaging, or perfusion CT, or dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).
Positron emission tomography for Bone Imaging, as an in vivo tracer technique, allows the measurement of the regional concentration of radioactivity proportional to the image pixel values averaged over a region of interest (ROI) in bones. Positron emission tomography is a functional imaging technique that uses [18F]NaF radiotracer to visualise and quantify regional bone metabolism and blood flow. [18F]NaF has been used for imaging bones for the last 60 years. This article focuses on the pharmacokinetics of [18F]NaF in bones, and various semi-quantitative and quantitative methods for quantifying regional bone metabolism using [18F]NaF PET images.
