Nuclear medicine involves injecting radioactive tracers and using gamma cameras to image how the inside of the body is working. A small amount of radioactive medication is administered and detected as it emits radiation, allowing special cameras to take pictures of organs and physiological processes. Different tracers can image various organs depending on where they accumulate. Single photon emission computed tomography (SPECT) improves on planar nuclear medicine imaging by using gamma camera rotation to generate 3D, cross-sectional images of the body.

1. NUCLEAR MEDICINE AND ITS
APPLICATIONS
PRESENTED BY:-
SARITA RAI
MRT12UGBBM010

2. Nuclear Medicine
Nuclear medicine is a medical speciality that involves
giving a patient a small amount of radioactive
medication, called a radiopharmaceutical. This makes
the body slightly radioactive for a short time.
A special nuclear medicine camera detects the
radiation, which is emitted (released) from the body,
and takes images or pictures of how the inside of the
body is working.
Many different organs can be imaged depending on
the type of radioactive medication used.

3. The radioactive medication is most commonly
injected into the blood stream through a vein,
but might be given in different ways, including:
•Swallowed;
•Injected directly into the tissue beneath the skin;
•Injected into A shunt;
•Injected into A joint; or
•Inhaled (breathed in).
Only a very small amount of radiopharmaceutical is
given to keep the radiation dose to a minimum.

4. What is a Gamma Camera
A gamma camera is machine
that is able to detect and
make images from the very
small amounts of ionising
radiation emitted from
patients having a nuclear
medicine study. The gamma
camera usually has a table,
often narrow, on which the
patient lies. The images are
taken using the camera
‘head’.

5. GAMMA CAMERA

6. Imaging techniques using gamma cameras
 Scintigraphy ("scint") is the use of gamma cameras to capture
emitted radiation from internal radioisotopes to create two-
dimensional images.
 SPECT (single photon emission computed tomography)
imaging, as used in nuclear cardiac stress testing, is performed
using gamma cameras. Usually one, two or three detectors or
heads, are slowly rotated around the patient's torso.
 Multi-headed gamma cameras can also be used for Positron
emission tomography scanning, provided that their hardware and
software can be configured to detect "coincidences" (near
simultaneous events on 2 different heads).

7. How is Nuclear Medicine different from normal
X-ray and CT examinations?
An X-ray or CT image is formed from ionising radiation (X-rays)
that passes through the body, but does not arise from the body;
whereas a nuclear medicine image is formed from the ionising
radiation (usually gamma rays) emitted from within the body. A
gamma ray has similar properties to an X-ray, but it arises from
the nucleus of an atom, whereas an X-ray arises from the
electron shell of an atom.
Another way that nuclear medicine is different from X-ray and CT
examinations is that an X-ray study shows what something looks
like. In nuclear medicine studies, the radiopharmaceutical
usually only goes to the part of the body or organ system if it has
some function and so shows how it is working.

8. Single Photon Emission Computed
Tomography (SPECT)
This SPECT technique uses a gamma camera to record
images at a series of angles around the patient. These
images are then subjected to a form of digital image
processing called Image Reconstruction in order to
compute images of slices through the patient.

9. SPECT
The gamma camera is typically rotated around
the patient in order to acquire the images.
Modern gamma cameras which are designed
specifically for SPECT scanning can consist of two
camera heads mounted parallel to each other
with the patient in between. The time required to
produce images is therefore reduced by a factor
of about two. In addition some SPECT gamma
cameras designed for brain scanning have three
camera heads mounted in a triangular
arrangement.

10. SPECT machine performing a total body
bone scan.

11. Applications
 SPECT can be used to complement any gamma
imaging study, where a true 3D representation
can be helpful, e.g.:-
• Tumor imaging,
• Infection imaging,
• Thyroid imaging
 Because SPECT permits accurate localisation in
3D space, it can be used to provide information
about localised function in internal organs, such
as functional cardiac or brain imaging.

12. Positron emission tomography
In modern PET-CT scanners, three dimensional imaging is
often accomplished with the aid of a CT X-ray scan
performed on the patient during the same session, in the
same machine.
If the biologically active molecule chosen for PET is
fluorodeoxyglucose (FDG), an analogue of glucose, the
concentrations of tracer imaged will indicate tissue
metabolic activity by virtue of the regional glucose uptake.
Use of this tracer to explore the possibility of cancer
metastasis (i.e., spreading to other sites) is the most
common type of PET scan in standard medical care (90% of
current scans). However, on a minority basis, many other
radioactive tracers are used in PET to image the tissue
concentration of other types of molecules of interest.

13. PET Acquisition Process

14. Applications:-
PET is both a medical and research tool.
• It is used heavily in clinical oncology (medical
imaging of tumors and the search for
metastases).
• PET is also an important research tool to map
normal human brain and heart function, and
support drug development.