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PART 1

GAMMA CAMERA

A device used to image gamma radiation emitting

radioisotopes (scintigraphy)

WHAT IS GAMMA CAMERA ?

To view & analyze images of the human body or distribution of medically injected, inhaled or

ingested radionuclides emitting gamma rays.

FUNCTION OF GAMMA CAMERA

HOW DOES IT WORK ?

COMPONENTS OF GAMMA CAMERA CALLIMATOR NAL (TI) CRYSTAL PHOTOMULTIPLIER TUBES (PMT) PRE- AMPLIFIER AMPLIFIER POSITION LOGIC CIRCUITS PULSE HEIGHT ANALYZER DATA ANALYSIS COMPUTER DISPLAY (CATHODE RAY TUBE etc.) GANTRY

CALLIMATOR

• Made of a large number of small holes drilled in a plate of lead.

• Provide the right direction.

• Scatter radiation absorbed by septa.

TYPES OF COLLIMATORPARALLEL - HOLE PIN- HOLE

COLLIMATOR

Image

Same Sizeas

Object

Sensitivity

CONT.CONVERGING DIVERGING

NAL (TI) CRYSTAL Converts received radiations into

light photons

PHOTOMULTIPLIER TUBES (PMT) Following the light

guide. photocathode converts

light photons into electrons.

electrons amplified through many dynodes.

The final electrons cluster is collected at the anode

anode converts them into electrical signals.

PRE- AMPLIFIER & AMPLIFIER Pre- amps attach above the

PMT. The amount of charge given by

PMT is very small. Even though we have used a sophisticated photo detector like a PMT we still end up with quite a small electrical signal.

A very sensitive amplifier is therefore needed to amplify this signal. This type of amplifier is generally called a pre-amplifier.

After that use amplifier to amplify the signal as need.

POSITION LOGIC CIRCUITS

Position circuitary receive the electrical impulses from the tubes in the summing matrix circuit (SMC). 

This allows the position circuits to determine where each scintillation event occurred in the detector crystal.

PULSE HEIGHT ANALYZER

The amplitude of each electrical pulse from the amplifiers is measured in the electrical circuits of the pulse-height analyzer

Peak height analyzer and a computer convert the light into a useful anatomical image

DATA ANALYSIS COMPUTER

A processing computer is used to deal with the incoming projection data and processes it into a readable image of the 3D spatial distribution of activity within the patient.  The computer may use various methods to reconstruct an image, such as filtered back projection or iterative reconstruction

GANTRY

A gamma camera system attached with gantry.

All circuits and motors related to movement (longitudinal, rotational, up & down)of gamma camera placed in gantry.

gantry

Bone scan. Myocardial

Perfusion Lung scan. Kidney function. Thyroid uptake.

APPLICATIONS OF GAMMA CAMERA

PART 2

RADIOPHARMACEUTICAL

Is a radioactive pharmaceutical agent that is used for

diagnostic or therapy in a tracer quantity.

DEFINITION OF RADIOPHARMACEUTICAL

RADIOPHARMACEUTICAL

THERAPEUTIC

DIAGNOSING

USE OF RADIOPHARMACEUTICAL

THERAPEUTIC Designed to deliver therapeutic dose of

ionizing radiation to specific disease site, such as cancerous tumors, with high specificity in the body.

Historically, used to treat Thyroid cancer, Graves’ disease, hyperthyroidism, and bone pain pallitation associated with skeletal metastasis.

DIAGNOSING

Used to derive detailed description of the morphology and dynamic functioning of the various internal organs of the

body.

PART 3

THE ROLES OF COMPUTER IN RADIOISOTOPES

IMAGING

data acquisitiondata processingimage display and manipulationdata storage and system control

Studies of the brain and central nervous system.

Cardiac imaging. Skeletal imaging. The respiratory system. Liver/spleen imaging. The endocrine system

RADIOISOTOPES IMAGING INCLINICAL APPLICATION