Principles and instrumentation of SPECT/CT
Yi-Hwa Liu, Albert J. Sinusas in Hybrid Imaging in Cardiovascular Medicine, 2017
Single-photon emission computed tomography (SPECT) is technology for creating three-dimensional (3-D) images of the distribution of radioactively labeled substances within a subject. The energy of the radiation emitted is high enough to penetrate the patient tissues, allowing visualization of structures at all depths inside the patient. The energy is too high to be seen directly with the human eye and so a specially designed high-density detector is used to measure the emitted signals. The detector provides a 2-D picture of the radiation. By rotating the detector around the patients, a collection of pictures is obtained that can be converted into a 3-D image of the radioactivity distribution. Because the radioactive label is attached to a substance, the images track where that substance goes after being injected into the body. Thus, images of the radioactivity distribution can provide information on the function of different organs and physiologic systems with respect to the injected substance. For example, images of the distribution of 99mTc-tetrofosmin indicate how well blood is flowing to the myocardial tissues. The information in the images is degraded, however, by interactions of the emitted radiation with the surrounding tissues in the patient. Computed tomography (CT) can provide an accurate picture of the patient’s anatomy, which can be used to significantly enhance the quality of the SPECT information. The combination of these two modalities thus provides a powerful tool for evaluating the heart. This chapter will describe the principles and instrumentation behind hybrid imaging with SPECT/CT.
Augmented Reality in Image-Guided Robotic Surgery
Terry M. Peters, Cristian A. Linte, Ziv Yaniv, Jacqueline Williams in Mixed and Augmented Reality in Medicine, 2018
SPECT uses gamma cameras to detect radiopharmaceutical tracers, similar to planar scintigraphy. The main difference comes from the ability of SPECT to reconstruct a 3D image using rotating planar images acquired over an arc around the patient, similar to CT. SPECT is often combined with x-ray CT. Together, SPECT/CT provides 3D images representing both the lymphatic system and anatomical structures. This combined imaging method is showing great promise, as sentinel lymph node (SLN) detection rates, as well as indirect metabolic activity, have been reported at 95% incidence and greater (Holman et al. 2014). A robotics SPECT for minimally-invasive SLN mapping was first introduced in 2016 (Fuerst et al. 2015). The authors used a drop-in gamma probe, manipulated with a robotic laparoscopic gripper, for intraoperative abdominal intervention. Evaluation and testing using a phantom for gynecological sentinel lymph node interventions compared to ground-truth data yielded a mean reconstruction accuracy of 0.67 mm.
Single-Photon Emission Computed Tomography (SPECT) Imaging System and Quality Control
Bhagwat D. Ahluwalia in Tomographic Methods in Nuclear Medicine: Physical Principles, Instruments, and Clinical Applications, 2020
SPECT cameras can accumulate data for transverse and longitudinal sections simultaneously during a single revolution. A SPECT system gives a total image, has the ability to eliminate under- and overlying activity, increases contrast relative to planar imaging, and has capability for quantitative measurement of radiopharmaceutical volume and concentration. The last characteristic when employed with newly developed single-photon radiopharmaceuticals and appropriate biological models, has resulted in the ability to quantitatively measure in vivo parameters, such as regional blood flow, noninvasively. During the last 15 years there has been marked development in both instrumentation and radiopharmaceuticals. Basically, there are two types of SPECT instruments, longitudinal and transverse section devices. Longitudinal planar system, rotating slant hole, and multipinhole belong to the first category. These devices are described in Chapters 7, 8, and 9, respectively. Longitudinal devices provide only longitudinal sections and collect data through limited angles, while the transverse section devices collect data at all angles.
Brain-targeting by optimized 99mTc-olanzapine: in vivo and in silico studies
Published in International Journal of Radiation Biology, 2020
Ahmed B. Ibrahim, Hesham A. Shamsel-Din, A. Samir Hussein, M. Alaraby Salem
The technology for brain diagnosis has become an important tool in both research and clinical care. Neuroscientists use that technology to visualize brain structure and function from the level of individual molecules to the whole brain, in order to recognize and diagnose neurological disorders, and develop new strategies for treatment (Saddar et al. 2014). The study aimed at utilizing drugs that cross blood-brain barrier to develop potential radiopharmaceuticals for non-surgical imaging of the brain. The evolution of brain-imaging radiopharmaceuticals has progressed quickly in recent years. Single Photon Emission Computed Tomography (SPECT) is a commonly used nuclear imaging technique in diagnosis, evaluation of therapeutic response, selection of medical or surgical treatment, and detection of benign or malignant tissue. All these uses are highly relevant to malignant brain tumors, head injuries, cardiovascular disease, epilepsy, dementia and movement disorders (Heinz et al. 2000; Bonte and Devous 2003; Bammer et al. 2005; Brooks 2005; Dickerson and Sperling 2005; Eckert and Eidelberg 2005; Kuzniecky 2005; Lee and Newberg 2005).
Prostate-specific membrane antigen-directed imaging and radioguided surgery with single-photon emission computed tomography: state of the art and future outlook
Published in Expert Review of Medical Devices, 2022
Luca Filippi, Barbara Palumbo, Viviana Frantellizzi, Susanna Nuvoli, Giuseppe De Vincentis, Angela Spanu, Orazio Schillaci
Nuclear medicine is based on the administration of radiopharmaceuticals aimed to investigate physio-pathological phenomena at a cellular and molecular level. After radiotracers’ injection and localization in the site of interest, imaging is obtained through the detection of the photons produced during the process of radioactive decay and the interaction with the neighboring tissues. When single-photon emitting tracers are employed, detection is carried out by gamma-camera through planar images and/or SPECT. The main advantage of planar images is their capability to register in real-time radiotracers’ biodistribution through dynamic acquisition, while the main limitation is the low sensitivity since only photons emitted parallel to the collimators (or within a certain angular region, if collimators different from parallel are employed) are allowed to reach the detectors [19]. SPECT is obtained by rotating detectors around the patient, so that it is possible to acquire the activity distribution under multiple angles, namely ‘projections,’ that are then reconstructed into a 3D volume through several software packages. Hybrid SPECT/CT, combining a variable-angle gamma-camera with an X-ray tube, allows an accurate co-registration of functional and anatomical images and also provides attenuation map of the patient [20].
Ethical and Legal Considerations of Alternative Neurotherapies
Published in AJOB Neuroscience, 2021
Ashwini Nagappan, Louiza Kalokairinou, Anna Wexler
In traditional health care settings, SPECT imaging is typically used to evaluate neurological diseases, such as stroke, epilepsy, and neurodegenerative disorders (ACR 2016). The SPECT imaging procedure consists of an IV injection of radioactive material, followed by a nuclear scan of the radioactive material in the brain (Cedars Sinai 2019). There are at least a dozen clinics in the U.S. offering SPECT scans for neuropsychiatric diagnostics and evaluations, such as CereScan, PathFinder, Neuro-Luminance Inc., DrSpectScan (CereScan 2020; DrSpectScan n.d.; Neuro-Luminance Inc. 2019; PathFinder 2020), and the eight locations of the Amen Clinics (2020b). At the Amen Clinics, the cost of an initial SPECT evaluation is approximately $4,000 (A. Nagappan, personal communication, July 24, 2020). The Amen Clinics claim that SPECT is useful both in the diagnosis of recognized clinical conditions listed in the Diagnostic and Statistical Manual of Mental Disorders (DSM) such as bipolar disorder, panic disorders, and attention deficit disorder (ADD), as well as their own variations of such conditions, such as the “Ring of Fire ADD,” “Overfocused ADD,” and “Limbic ADD” (Amen Clinics 2020c). In addition, a few clinics make more general promotional statements about the use of SPECT to improve brain health (DrSpectScan n.d., Cerescan 2020.).
Related Knowledge Centers
- Gamma Camera
- Gamma Ray
- Radionuclide
- Scintigraphy
- Tomography
- Radiography
- Nuclear Medicine
- 3D Computer Graphics
- Radioligand
- Radiopharmaceutical