BIOMEDICAL ENGINEERING SYSTEM

Introduction to single photon emission computed tomography(SPECT)

KHALEEQUE AHMED

Engr Khaleeque AhmedSir syed university of engineering &

technology Karachi

Anger camera Hal O. Anger invented

the scintillation camera in 1958

Established basic design:NaI(Tl) crystalPMT arrayPosition weighted

signals Hal O. Anger

Single photon emission computed tomography(Spect)

Spect is a nuclear medicine technique used to create 3D representation of image by 3D deimensional distribution of radiopharmaceutical with in the patient’s body.

Spect technique itself a gamma cameraSpect is executed through gamma cameraIt’s also called moving gamma cameraWhile gamma camera is a stationary

CONT…….. SPECT use radiopharmaceuticals same as that are

routinely used in all nuclear medicine department radiopharmaceuticals Technetium iodide & technetium 99m

While crystal is thallium activated sodium iodide

PULSEHEIGHT

ANALYZERPOSITIONSIGNALS

ENERGYSIGNAL

X Y Z

Image Display

COLLIMATOR

NaI(Tl)Crystal

. . . . . . .

PMT ARRAY

Scintillation camera componentsDetector

NaI(Tl) crystal

Photomultiplier tube (PMT) array

Analog-to-digital converters (ADCs)

Collimator

Low energy

Medium energy

High energy

Axial shields (coincidence imaging)

Pinhole

Scintillation camera componentsComputer(s)

Acquisition

Processing

Acquisition & processing

Physicians viewing

Patient Table

Pallet

Accessories

Collimation

Purpose: To project gamma ray distribution onto the detector

Basic design

Distance performance

Spatial resolution vs. count sensitivity

25 mm

1.2 mm

Collimators are fabricated from lead.

Gamma rays that hit the septa are absorbed.

Image forming aperture of the scintillation camera.Limiting component in spatial resolution & count sensitivity.

SPECT Reconstruction Algorithms

FBP (Filtered Back Projection)

Iterative reconstruction

2D3D

FBP 3D 2D

e.cam 3/8”Hx: 36-year-old female. Indication staging for osteosarcoma

Myocardial perfusion SPECT

FBP

Flash 3D

2D Iterative

Clinical ApplicationsPlanar & SPECT Cardiac

Whole-body bone

Renal

Gastric

Hepatobiliary

Thyroid

Pulmonary

Brain

Thank you……..