TRAINING ON X-RAY SCREENING

Principles of X-Ray Imaging &

Operations

Instructor: Ibrahim Athif

Objectives Switch on a typical X-ray machine &

operate it safely Interpret images on monitor & identify

items that maybe hidden or camouflaged.

Detect prohibited items using modern X-ray equipment in accordance with appropriate procedures.

Introduction

There is a need for X-ray screeners and security managers to understand:

• The principle of operations and characteristics of X-ray systems

• Advantages and limitations

• Proper method of use

Basic principles of X-ray imaging

If an X-ray beam is projected to a fluorescent screen, the coating on the screen will glow.

An object placed between the X-ray beam and the screen will absorb some of the X-ray radiations making a shadow on the screen.

Denser the image - Darker the image

X-ray Fluorescent screen

X-ray Fluorescent screen

object

Modern equipment

Mechanical conveyer takes the item from the loading point, through the inspection tunnel and out of the loading point.

The conveyer speed is usually preset at 0.2M/SEC (39FT/MIN)

Advances in X-ray imaging

X-rays emitted by a generator are collimated to a fan shaped beam.

The item to be screened is moved across the beam on a conveyor along a tunnel.

The item is scanned in slices. Collimated beam projected

from an X-ray generator to the moving object.

The corresponding X-ray image scrolls on to the monitor screen

Advances in X-ray imaging

The item is scanned in slices. Collimated beam projected from an

X-ray generator to the moving object. The corresponding X-ray image

scrolls on to the monitor screen

What does an X-ray Image Represent?

It comprises of shapes defining the areas of the scanned items where the X-ray met various levels of resistance to penetration.

The degree of resistance to penetration is shown as levels of shade varying from black to white.

Useful enhancement features

Latest technologies provide additional features to

enhance the quality of the image.

Generation of X-rays capable of penetrating up

to 25mm of steel. Improved resolution capability to define the

image of a 38 A WG (0.10MM) solid wire Electronic zooming function

Permissible X-ray dosage

There is a limitation to the dosage of X-ray which

can be applied in screening.

The dosage must comply with the limits imposed

by health and safety regulations

In the airport environment, we must ensure

absolute safety of hypersensitive items such as

photographic films.

Permissible X-ray dosage

Modern X-ray systems guarantee the safety of

photographic films of up to 1600 ASA even after

repeated exposures.

Regulations prohibit security X-ray screening of

live creatures.

Conveyor system Visible cables & connections Exterior of equipment Leaded curtains Console & controls Monitor

Checks before start-up

Lead curtains

Lead curtains are fixed at loading and unloading ends.

Check for tears and missing strips

Do not operate the X- ray unit if there are defective leaded curtains.

Conveyor System

Check the conveyor belt for:• damages

• heavy dirt

• objects which may have fallen between the rollers

Safety Rollers

Between the conveyor belt and the roller input & out put conveyors, a SAFETY ROLLER is located. Check if this can be lifted about 10cm. (the safety roller must not be fixed in any way)

General Safety Instructions

Ensure that the X- ray unit is supervised as long as it is switched on.

Ensure that nobody sits or stands on the conveyors or touches moving parts.

Ensure that no person puts a hand into the X- ray tunnel, when the unit is activated.

General Safety Instructions

Keep liquids, dirty objects, etc… away from the X- ray unit; use a proper container to screen them.

Do not cover ventilation openings. Control the conveyor so that nobody risks

to be injured by falling baggage or freight items and no baggage or freight item is damaged.

Why these safety instructions are so important ?

X- Ray machines generate X- ray radiation

X - Ray radiation is harmful to living things

Useful information

The local dose on a HEIMANN X- Ray system is 0.0025msv/h at maximum which can be used to penetrate 15mm steel.

Typical internal dose in the X-ray system is 0.0012- 0.0016msv/h

The local dose is measured at 5cm.

Basic operations

Wait while the power –on indicator and the wait

indicator light up and the unit carries out the self

test.

If required, you can adjust contrast and

brightness and colour levels of the test image

can clearly be distinguished.

Setting X-ray inspection system in to operation

A test pattern is displayed on the monitor the X-

ray inspection system is ready for operation.

In case of any hazard to persons or animals

staying near the X-ray system, the system can

be switch off via the EMERGENCY STOP key at

any time immediately

Placing objects into the system

In systems with a tunnel opening which is bigger

in width than height, the objects are transported

upright for good view.

The distance between two objects to be

inspected must be at least 30cm.

Operating the system

After activation of the key GO the object is

transported into the inspection tunnel

The X-ray generator is switch on.

Item is scanned line by line. Together with the

moving item the corresponding X-ray image

scrolls onto the monitor screen.

Operating the system

The complete X-ray image has become

visible on the monitor the conveyor belt can

be stopped by means of the key STOP, or

image will be overwritten by the next

image. In case of risk stop the conveyor

IMMEDIATELY VIA STOP.

Operating the system

In case suspect items are found in the

inspection, such items will be marked via key

MARK

The baggage or item can only be marked when it

is completely visible on the screen.

Interpreting images

Interpreting X-ray images can be tricky.

What we see on the monitor is a flat view of a 3D

object.

Its orientation on the conveyor influences the

shape presented on the monitor.

Interpreting is not easy!

Experience will make you effective.

Constantly observe the monitor

Don’t get distracted by long queues

Your job is scrutinizing the object in the image.

The fundamental properties of X-rays images

The penetration depends on the density and thickness of the X-ray examined material

In standard X-ray images (black/white), objects can only be identified by there shape.

Imaging systems

There are two imaging systems that are used for x-ray presentation:

• Computer aided tracing (CAT)

• Multi imaging technique (MAT)

Function HI-CAT

HI-CAT is applied for the distinction of smallest

absorption differences in the material inspection.

All metals are shown in red and other materials

are in black and white.

The MAT system

Enables operators to differentiate between

organic and inorganic materials.

The MAT system presents different types of

materials on the screen within a four band colour

range.

The bands are related to the atomic weight.

Material Identification by colour

BAND ATOMIC # MATERIALS &

COMPOUNDS

1.ORANGE 1-10 Lighter elements: hydrogen, carbon, nitrogen, oxygen and the molecular compounds of the latter, the organic materials

BAND ATOMIC # MATERIALS

&

COMPOUNDS

2.GREEN 11-18 Medium heavy elements ; aluminum, sodium, chlorine

Cooking salt

BAND ATOMIC #

MATERIALS&

COMPOUNDS

3. BLUE 19-100 Heavy elements: metals like titanium, chromium ,iron, nickel ,copper, zinc, tin, lead, gold, silver, etc

BAND ATOMIC #

MATERIALS &

COMPOUNDS

4.BLACK 100+ Items that cannot be penetrated by X-ray

Objects of higher thickness

They appear in dark blue or black colour on the

screen

The object should be inspected manually

Always evaluate the whole image

If you think you should search an item, then

search it, rely on your instinct.

Special functions

Organic only (O2) and organic stripping (OS) If you apply the O2 function, you can limit the

display to organic material. If you apply the OS function, you can limit the

display to inorganic materials

HIGH

The above mentioned image display modes you

can detect items hidden behind high-absorbing

items become more clearly visible. Even thicker

layers of light organic materials (explosives,

drugs) are definitely emphasized. At the same

time, low- absorbing objects are filtered out.

NEG

In the negative image, high –absorbing objects

appear bright, low-absorbing appear black. This

way, smaller or thinner objects of higher density

(e.g.: wires) become more clearly visible.

SEN

The above mentioned image display mode you

can obtain an optimum contrast over the whole

X-ray image by means of electronic real time

processing

The objects of lower density can be easily

detected (e.g.: explosives)

SEN

Organic only (O2)

Organic stripping (OS)

MAT

BLACK & WHITE

NEGATIVE

Application of X-ray in detecting drugs

1025 grams of Heroin detected by X-ray

X-ray image detected a suspicious powder like

substance inside a casserole pot . By

dismantling it, officers found 1025 grams of

heroin. (the passengers carrying it was 2 old

couple travelling from India after a medical trip.

As these couple didn’t show any nervousness, by

questioning it was found that, it was given to

them by a friend.

Application of X-ray in detecting drugs

1030 grams of Hashish Oil detected by X-ray

Application of X-ray in detecting drugs

During X-ray screening operator found that the

bottom of the pot contains an unusual

substance, By dismantling it, found 1030 grams

of hashish oil. (the passenger carrying it was

travelling from India. The passenger didn’t show

any nervousness , by questioning ,found it was

given to him by a friend.

Application of X-ray in detecting drugs

1.080 KG of Heroin detected by X-ray

Application of X-ray in detecting drugs

X-ray operator found that the sides of the box are

too dark. By opening the package customs

officers found that the sides of the card board

box was cut open and filled with 1.080Kg of

heroin packed in polythene and carbon paper.

Rotation of screening operators

Fatigue and boredom seriously diminish the

ability of operators to focus on the task.

The causes of this deterioration include:

Strain on the eyes.

Boredom of making repeated judgments.

Always take your time.

Never work under time pressure.

Security of people and property depends

decisively upon your work.

Stop conveyor if you think, you need more time

to examine an image.

Remember the fact that X-ray unit doesn’t

automatically detect weapons, drugs or

prohibited items.

Trust your sixth sense

An image may be clear as crystal, but your sixth

sense may say that something is wrong.

Trust that sixth sense.

Do not ignore the potential danger

Rotation of Screening Operators

Operate X-ray (20min)

• Other tasks (40 min)

Detection of Items

Most common ways used to prevent

detection of items are:

› Disguise.

› Dismantle.

› Camouflage.

Summary

Imaging systems.

Function HI-CAT.

The MAT system.

Organic only (O2).

Organic stripping (OS).

HIGH, NEG, SEN.

Colour Band.

Q & A