RAD TECH A WEEK 2 RADIOGRAPHIC EQUIPMENT Spring 2009

Radiographic Room

OBJECTIVES IDENTIFY GENERIC COMPONENTS OF THE RADIOGRAPHIC EQUIPTMENT DESCRIBE VARIOUS PLANES OF X-RAY TUBE AND TABLE MOVEMENT DISCUSS CONTRAST & DENSITY “ EXPOSURE FACTORS”

X-RAY TUBE MADE OF PYREX GLASS TO WITHSTAND HIGH HEAT LOAD IS GAS EVACUATED –(so electrons won’t collide with the air molecules in the tube)

XRAY TUBE HOUSING MADE OF LEAD AND STEEL TO ABOSRB ANY STRAY RADIATION TO PREVENT X-RAY PHOTONS TO LEAK FROM THE TUBE

TUBE HOUSING MADE OF LEAD & STEEL

THE X-RAY TUBE Glass encased in a sturdy lead and steel housing Primary components ANODE (+) & CATHODE (-)

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X-Ray Machine Purpose: –provide a specific current (mA) & voltage (kV) to the x-ray tube –convert electrical energy to electromagnetic energy (x rays) in a controlled manner control the energy of the x-ray photons control the number of photons

kVp & mAs

Early X-ray Tube

THE X-RAY TUBE The X-Ray tube is the single most important component of the radiographic system. It is the part that produces the X- rays

How Are X-rays Made? X-rays are produced when electrons strike a metal target. The electrons are released from the heated filament and accelerated by a high voltage towards the metal target. The X-rays are produced when the electrons collide with the atoms (electrons) of the metal target.

X-ray PHOTONS Electromagnetic waves Shorter wavelength and higher energy than normal light. Wave-particle duality –Photons can be described both as waves and particles.

The Electromagnetic Spectrum X-rays have wavelengths much shorter than visible light, but longer than high energy gamma rays MEASURED IN ANGSTROM 0.1 – 0.5 FOR X-RAYS

PRODUCTION OF X RAYS Requirements: –a source of fast moving electrons –must be a sudden stop of the electrons’ motion –in stopping the electron motion, kinetic energy (KE) is converted to EMS energies Infrared (heat), light & x-ray energies

How “X-rays” are created Power is sent to x-ray tube via cables mA (milliamperage) is sent to filament on cathode side. Filament heats up – electrons “boil off –Thermionic emission Negative charge

How “X-rays” are created Positive voltage (kVp) is applied to ANODE Negative electrons = attracted across the tube to the positive ANODE. Electrons “slam into” anode – suddenly stopped. X-RAY PHOTONS ARE CREATED

How “X-rays” are created Electron beam is focused from the cathode to the anode target by the focusing cup Electrons interact with the electrons on the tungsten atoms of target material PHOTONS sent through the window PORT – towards the patient

How “X-rays” are created SEE: MAN MADE RADIATION (PG.93) TO PRODUCE X-RAYS YOU NEED: A SOURCE OF ELECTRONS A FORCE TO MOVE THEM QUICKLY SOMETHING TO STOP THEM SUDDENLY

e- X-ray Production Electrons move at high speed (KE) Collide with target on anode KE of electrons converted to x rays & heat electrons anode target

Focusing Cup focuses stream of electrons

HIGH VOLTAGE TO ANODE – ATTRACTS – ELECTRONS FROM CATHODE CURRENT TO STATOR CAUSES ROTATION OF ANODE

Anodes - Target Cu W Common target material is Tungsten Molybdenum or Graphite base Rotating Anodes 2” to 5” disk (focal track)

X-ray Tube Anode  Tungsten anode disk  Stator and rotor make up the induction motor  Rotation speeds  Low: 3,000 – 3,600 rpm  High: 9,000 – 10,000 rpm  Molybdenum stem (poor heat conductor) connects rotor with anode to reduce heat transfer to rotor bearings  Focal track area (spreads heat out over larger area than stationary anode configuration)

Rotating Anode

TABLE OR UPRIGHT BUCKY TRAY

The ‘BUCKY’ The bucky is the device in the table or chest board that holds the film cassette. The ‘bucky’ is like a drawer that opens and closes to insert and remove the film cassette.

Tables Tilting rooms are designed for both diagnostic and fluoroscopic work –Tilting models usually tilt to 90 degrees in one direction and 15 – 30 degrees in the other direction –Tilting models include ancillary equipment; footboard, shoulder support, handgrips, compression bands

Tube Supports Designed to help technologists with various tube locations for creative imaging. Tube suspension systems are available in 5 versions

Tube Movement Longitudinal Transverse Vertical Angling or Rolling Rotating Telescoping

Radiographic grid & bucky tray

COLLIMATOR ATTACHES DIRECTLY BELOW THE X-RAY TUBE SERVES AS A X- RAY BEAM LIMITING DEVISE CONTROLS THE SIZE AND SHAPE OF X-RAY FIELD

Cone collimator

ALWAYS KEEP THE COLLIMATED AREA SMALLER THAN THE SIZE OF THE CASSETTE

RADIOGRAPH PERMANENT RECORD MADE USING RADIATION –RADIO-RADIATION (usually x rays) –GRAPHPERMANENT RECORD

UNEXPOSED FILM PLACED IN A CASSETTE

CASSETTE or FILM HOLDER The CASSETTE is used to hold the film during examinations. It consist of front and back intensifying screens, and has a lead (Pb) backing. The cassette is light tight

CONTROL CONSOLE GIVES THE TECHNOLOGIST CONTROL OF THE X-RAY MACHINE TECHNIQUE SELECTION Located OUTSIDE of the Radiographic Room

The Control Console The control console is device that allows the technologist to set technical factors (mAs & kVp) and to make an exposure. Only a legally licensed individual is authorized to energize the console.

“Technique” kVp, mAs (mA x s) What is set at the control panel How the “image” is created on the “film” or Image receptor (digital) kVp controls the “ENERGY” of the beam The Higher kVp – more penetrating Ranges is in Diagnostic x-ray

“Technique” kVp, mAs (mA x s) mA- is the current in combination with the time – determines HOW LONG the beam will stay on Controls the density on the film/image

IMAGE CREATION ATOMS INTERACTION WITH “MATTER” ATOMIC NUMBER

Barium has a higher z# more asorbtion of photons

Why you see what you see The films or images have different levels of density – different shades of gray X-rays show different features of the body in various shades of gray. The gray is darkest in those areas that do not absorb X-rays well – and allow it to pass through the images are lighter in dense areas (like bones) that absorb more of the X-rays.

FLUOROSCOPY IMAGES IN MOTION

FLUOROSCOPY must wear shielding while x-ray beam is on

REMOTE ROOM & OLD CONVENTIONAL FLUORO

MOBILE / PORTABLE UNITS

When patients cannot go the the Radiology Deparment The equipment is taken to their room for imaging

What is in the Darkroom?

Safe Light 7-15 Watts Red filter Must be 3-6 feet from counter top or feed tray of processor Used to be amber or orange filter

Darkroom

CR processor What does a digital processor look like?

Other x-ray stuff…. Positioning phantoms Pixie

Other x-ray stuff…. Positioning sponges Lead markers Gurney

Radiographic Equipment X-ray Tube Construction G F E D C A B

A. Glass housing (envelope) B. Molybdenum neck of the anode C. Stators /Electromagnets D.Tungsten anode (focal spot) E. Window or port for beam exit F. Filament (cathode) G. Focusing cup