Description of single positron elmulsion ct

1. SPECT/CT AND CLINICAL
APPLICATION.
KAMPALA INTERNATIONAL UNIVERSITY-WESTERN CAMPUS, UGANDA
PRESENTER: DR. DAVID MICHAEL (RADIOLOGY-RESIDENT)
SUPERVISOR: DR. RICHARD EMBATI (NUCLEAR MEDICINE)
DATE: 13 AUGUST 2025

2. Objectives
• General overview of SPECT and components
• SPECT Mechanism of Action
• Types of SPECT
• Clinical applications of SPECT
• Precautions

3. Why SPECT?
• Similar to X-ray, Computed Tomography (CT) or Magnetic Resonance Imaging
(MRI), Single Photon Emission Computed Tomography (SPECT) allows us to
visualize physiological functional information about a patient's specific organ
or body system.
How does SPECT manage to give us functional information?
• Internal radiation is administered by means of a pharmaceutical which is
labeled with a radioactive isotope. This so-called radiopharmaceutical, or
tracer, is either injected, ingested, or inhaled.
• The radioactive isotope decays, resulting in the emission of gamma rays.
• These gamma rays give us a picture of what's happening inside the patient's
body.

4. How do these gamma rays allow us to see inside?
• By using the most essential tool in Nuclear Medicine, the gamma camera.
• Gamma camera can be used in planar imaging to acquire 2-dimensional
images or in SPECT imaging to acquire 3-dimensional images.

5. What is SPECT?
SPECT is short for Single Photon Emission Computed Tomography.
• As its name suggests (single photon emission), gamma ray emissions are
the source of information, rather than X-ray transmissions as used in
conventional Computed Tomography.
• Type of Nuclear imaging test that shows how blood flows to the tissues
and organs, which means it uses a radioactive substance and a special
camera (Gamma camera)
How are these gamma rays collected?
• They are emitted from within the patient, enabling us to reconstruct a
picture of where the gamma rays originated. From this, we can determine
how a particular organ or system is functioning.

6. • natural elements will pass safely through the body and be detected by The
radioisotopes typically used in SPECT are Iodine-123, Technetium99-m,
Xenon-133and Flourine-18. These radioactive forms of the scanner.
• The test differs from PET in that tracers will stay in the bloodstream rather
than being absorbed by surrounding tissues thereby limiting images to the
areas where blood flows. SPECT scans are cheaper and more readily
available than higher resolution PET Scans

11. TYPES OF SPECT MACHINES
SPECT can be categorized based on:
i. Detectors
ii. Configurations
iii. Intended clinical applications.
Common types:
• Brain SPECT for neuroimaging: high sensitivity and resolution to visualize brain function
and structures, Dx Seizures, Stroke, and Dementia.
• Cardiac SPECT: For heart imaging, assess blood flow, identify areas of ischemia or damage,
and evaluate heart muscle function.
• Bone SPECT: Detect abnormalities in bone metabolism, such as fractures, arthritis, or
tumors. They can reveal subtle changes in bone activity that may not be visible on
conventional X-rays.

12. • Specialized systems like SPECT/CT.
These systems vary in detector types, collimator designs, and software
algorithms to optimize performance for specific imaging needs.
Multi-headed SPECT:
Systems with multiple detector heads (e.g. dual-head, triple-head) that can
acquire data from multiple angles simultaneously, reducing scan time and
improving images

14. KEY COMPONENTS AND TECHNOLOGIES:
Detectors:
• Sodium Iodide(NaI) detectors are common, but newer systems use semiconductor-
detectors Eg.Cadmium Zink telluride(CZT): offering improved energy resolution and
compactness.
Collimators:
• These devices filter gamma rays, impacting spatial resolution and sensitivity. Common
types include parallel-hole, fan-beam, and cone-beam collimators.
Gantry Systems:
• The rotating gantry that holds the detectors allows for the acquisition of projection
images from multiple angles.
Software:
• Reconstruction algorithms and data correction methods are crucial for generating high-
quality images from the acquired data.

15. SPECT components
Basic components of a single photon imaging device (Anger camera) used for planar or single photon
emission computed tomography (SPECT) imaging. PHA = pulse height analyser; PM =
photomultiplier.

19. SPECT'S CLINICAL APPLICATIONS:
1. Cardiology
• Detecting coronary artery disease:
• SPECT can identify narrowed or
blocked coronary arteries, helping
diagnose conditions like atherosclerosis
and assessing myocardial perfusion
(blood flow to the heart muscle).
Assessing heart function:
• It can evaluate how well the heart
muscle is working and identify areas of
damage or scarring.

20. 2. Neurology:
• Diagnosing and monitoring
brain disorders:
• Dx Dementia, Parkinson's
disease, and epilepsy: blood
flow patterns and identifying
affected areas.
• Evaluating stroke and head
trauma: Extent of damage
from stroke and TBI and
monitor recovery.
• Detecting brain tumors:
Identify and characterize
brain tumors, sometimes in
conjunction with CT or
MRI.
SPECT and 18 F-FDG PET images for a patient with brain glioblastoma.
Tumor angiogenesis and tumor metabolism are well visualized on 99m
Tc-IDA-D-[c(RGDfK)] 2 SPECT and 18 F-FDG PET images, respectively.
Tumor localization corresponds across all images

21. 3.Orthopedics:
• SPECT scans can be used
to detect and evaluate
bone infections, stress
fractures, and bone
tumors.
• Also be helpful in
assessing the healing of
fractures and the
integration of joint
replacements.

22. Patient with Neck pain.
SPECT-CT shows hypermetabolism in
C4-C5 vertebrae endplate
CT shows severe degenerative
changes in vertebral endplatates with
reduction of disc spaces, endplate
osteophytes formation.
Hypermetabolism on SPECT correlates
with degenerative endplate changes
on CT.
Scan acquisition: 32 stops per detector
Total scan time: 7 min
Image reconstruction: 256x256 matrix
Injected dose: 99m Tc HMDP
Post injection delay: 2 Hours

23. • SPECT also in kidneys, thyroid, and other organs, as well as to
investigate cancer spread.

24. 4. Lung SPECT Asess lung
• Pulmonary Embolism (PE) Diagnosis: V?Q (Ventilation/Perfusion
SPECT) is a key tool for diagnosing Detect mismatches between
ventilation and perfusion, which are characteristic of PE. SPECT/CT
(combining SPECT with computed tomography) provides both functional
(SPECT) and structural (CT) information, enhancing diagnostic accuracy,
particularly in complex cases.
• COPD (Chronic Obstructive Pulmonary Disease): Can reveal
ventilation-perfusion mismatches , Pneumonia: stripe sign" (preserved
perfusion along the pleural border).
• Lung Cancer: Dx, Treatment planning by assessing the feasibility of lung
resection surgery and estimating post-operative lung function.
• It can provide a more accurate estimation of predict Post OP Lung
function

25. Fig. 6.4 Representative ventilation, perfusion, and fused SPECT/CT images in a patient with multiple PEs
(arrows). Workstation review should include triangulation of any defects to determine if there is V/Q mismatch
and if there is any underlying structure or abnormality on the CT.

26. Precautions:
1.Allergies/ Hypersensitivity: radiopharmaceuticals.
2. Pregnancy and Breastfeeding: Contraindicated
3. Medications and Supplements: Like dipyridamole and other
phosphodiesterase-3 inhibitors, may need to be avoided for a period before
the scan due to potential interactions with the procedure.
Caffeine should be avoided for at least 12 hours before the study, as it can
affect cerebral blood flow and interfere with medications used during the
scan.

27. 4. Dietary Restrictions: (NPO) for at least 3 hours before
5. Other Considerations: Remove all jewelr, Put on comfortable clothing
with minimal metal.
History of claustrophobia Make pt feel more comfortable during the scan.
For pediatric patients, ensure they are calm and prepared for the
procedure, potentially involving a parent or guardian in the process.
6. Radiation Exposure: The amount of radiation used in SPECT scans is
generally low and considered safe for most individuals.

28. Referrences
• Fred A. Mettler, Jr. 2019. Essentials of Nuclear Medicine and
Molecular Imaging 7th
edition, Elsevier, Inc.
• National inistitute of biomedical imaging and engineering
2017 nuclear medicine
• M.vharshini. Nuclear medicine. PowerPoint slides
• Radiopaedia

29. THANK YOU