Ch 1. RAD 105 Intro to Rad

- W.C. Roentgen
- H.C. Snook
- William Coolidge
- Michael Idvorsky Pupin
- Thomas Edison
- Charles Dally
- George Eastman

Who are the pioneers of the field of X-ray?

W.C. Roentgen

German physicist who Discovered X-ray in November 8, 1895 while working with a Crookes Tube at the University of Wurzburg.

H.C. Snook

Developed the interrupterless transformer

William Coolidge

Designed the hot cathode x-ray tube, which was introduced in 1910

Michael Idvorsky Pupin

Demonstrated the radiographic use of fluorescent screens, now called intensifying screens.

Thomas Edison

Invented the first fluoroscope and discovered many usage of fluorescent chemicals in radiography.

Charles Dally

Assistant and long time friend to Thomas Edison whom served as a test subject and resulted of severely burning his arm, later being amputated. Died in 1904 because of exposure.

George Eastman

- Founder of Eastman Kodak Company
- Invented photographic film using cellulose nitrate as a substitute for glass.
- Produce first radiographic film in 1914.

The first anatomic radiograph image produced by Roentgen

- An image of his wifes hand

First documented medical use of x-ray in U.S.

- February 1896
- Exam of boy's fractured wrist
- Performed at Dartmouth College

Early radiographers path

Physicists => Physicians (developed x-ray procedures and photographic plates) => Assistants (X-ray Technicians)

Radiography Education

- On the Job training of X-ray technicians evolved to hospital based education
- 1950s education for radiation therapy separated from radiography.
- Then community colleges, 2 years academic education
- Now, Some 4 years colleges

Four basic requirements for production of X-ray:

- A vacuum tube (xray tube)
- Electron source (filament, cathode)
- A target for the electrons (anode)
- High potential difference (voltage) between the electron source and the target

Container for the actual x-ray tube

- Referred to as a glass envelope
- Made of borosilicate glass (pyrex)
- Mainly used to withstand heat.
- Air is removed so that gas molecules will not interfere with x-ray production.

Cathode end, wire filament

- Source of electrons, Negative end
- Made of tungsten ( to withstand heat)
- Large atom with 74 electrons orbitting around a nucleus.
- Electric current flows through filament to heat. Then accelerates the orbiting electrons and increases distance from t

Anode end, Target

- Positive end of X-ray tube, opposite the filament
- Made of tungsten (to withstand heat)
- Smooth hard surface
- Site to where electrons travel too.
- Place where x-rays are generated.

Electron Stream

High positive electrical potential attracts the negative charged electrons of the space charge, which moves rapidly across the tube.
- 99% HEAT, small amount is converted to x-ray after the collision of the electrons to target, kinetic energy is converted

Electromagnetic Energy

Energy that have property of both electrical and magnetic
- All moves through space at same velocity, 186,000 miles/sec, which is 30 billion cm/sec

Photon

- Smallest unit of electromagnetic energy
- "Bullet of energy"
- Occur in groups or bundles called quanta, or quantum(singular)

Sine Wave

- Sinusoidal Form
- Repeating waveforms created be changes in the EM field. (Crest and Valleys)
- Amplitude
- Wavelength
- Frequency

Amplitude

- Distance from crest and valley of a sine wave
- Height of a sine wave

Wavelength

- Most important to radiographers
- Distance from one crest to another

Frequency

- Number of times per second that the crest passes a given point.

Formula for velocity

#NAME?

Electromagnetic Spectrum

- Therapeutic x-ray - 1/100,00nm IONIZING
- Gamma rays - 1/10,000nm IONIZING
- Diagnostic x-ray - 1/10nm IONIZING
- UV rays - 10nm NONIONIZING
- Visible light - 1000nm NONIONIZING
- Infrared rays - 10,000nm NONIONIZING
- Radar - 1/100m NONIONIZING
- Telev

Ionizing radiation

- Radiation with a wavelength SHORTER than 1nm
- It has sufficient energy to remove an electron from an atomic orbit.
- Ex. Therapeutic X-ray, Gamma rays, Diagnostic x-ray

Nonionizing radiation

- Radiation with wavelength LONGER than 1nm
- Insufficient energy to remove an electron from an atomic orbit
- Ex. UV rays, Visible Light, Infrared, Radar, Television, Radio

Characteristics of Radiation

- Travels in straight lines at the speed of light
- Affects photographic emulsions
- Affects biological tissues (ionizes atoms)
- Cannot be focused or refracted
- Cannot be detected by human senses

Attenuation

Effect on the x-ray beam caused by passing through matter.

Remnant Radiation

-Remains of the primary beam after it has been attenuated by matter, Patient or table
- Also known as Exit Radiation
- Travel Pattern - Pattern of densities in the matter results in differential absorption, therefore the pattern is inherent
- Energy Level

Scatter Radiation

- Happens When primary x-ray beam is attenuated by solid matter, patient or x-ray table.
- Energy level - Generally has less energy than primary x-ray beam.
- Primary source of occupational exposure
- Prevented by using Grids or Buckys into getting into t

Primary X-ray beam

- X-ray beam that leaves the tube and not attenuated by matter, except by air.
- Beam between the patient or IR.
- Cone-shaped beam, from focal spot.
- Travel pattern - Direction and location are predictable and controllable
- Energy Level - Controlled by

Focal Spot

- Very small area on the target(anode) end
- Actual size of the largest is no more than a few millimeters in diameter.
- This is where the primary x-ray beam exits from

Radiation Field

- Cross section of the x-ray beam at the point where it is used.

CR- Central Ray

- A photon in the center of the primary beam and perpendicular to the long axis of the x-ray tube

Detent

- Special mechanism that tends to stop a a moving part in a specific location.
- Used when the transverse tube position is centered to the table.

Collimation

- X-ray beam size is restricted by the size of the port.
- Increase the size of the port, you increase the size of x-ray beam. Decrease the size of the port, you decrease the size of x-ray beam.

Collimator

- Attached to the housing of the Tube
- Device that enables the radiographer to further control the size of the radiation field.
- Has a centering light to center the IR , usually stays on 15-30 seconds.

Dual focusing filament

- Found on the Cathode (-)
- Has one large and one small on focusing cups that direct the electrons to the same general area.

Large filaments

- is in the cathode, on a focusing cup
- used in combination with a large focal point for larger exposure.
- EX. Lumbar spine exams or abdominal exams

Small filaments

- is in the cathode, on a focusing cup
- used in combination with a small focal point for smaller body parts.
- EX. Exams on toes and wrists

Tube supports

- Tube housing are usually attached to a ceiling mounted tube hanger or mounted on a tube stand.
- Provides support and mobility for the tube

Ceiling mounted tube hanger

- Suspended from the ceiling on a system of tracks to allow positioning of the tube.
- useful when positioning the tube over a stretcher or moving the tube for use in different locations.

Tube Stands

- Is vertical support with a horizontal arm that supports the tube over the table.
- Rolls along t a track that is secured to the floor, permitting horizontal motion.

X-ray tube housing

- Its a protective-barrel shaped housing that protects the x-ray tube.
- incorporates shielding that absorbs radiation that is not part of the useful x-ray beam.

Radiographic Table

- Specialized equipment that is mainly used for the support of the patient.
- Capable of several types of motion: vertical, tilt and "floating"
- Vertical table motion - hydraulic motor activated by hand, foot or knee switch.
- Motioned to place patient i

Bucky tray

- Helps absorb scatter radiation
- Holds the Image Receptor (IR) within the x-ray table
- Usually located beneath the table surface.
- Whole unit can be moved along the length of the table and locked into position where desired.
- Mainly used, along with

Grids

- Helps absorb scatter radiation.
- Plate made of tissue-thin lead strips, mounted on the edge, with radiolucent interspacing material.
- Usually moves during the exposure, to blur the image of the thin lead strips so not visible on the radiograph.
- Some

Upright image receptor unit

- Has a upright bucky or grid cabinet to hold the IR in the upright position.
- Referred as grid cabinet, when stationary grid is included.
- when grid moves during exposure its called a upright bucky

Transformer

- Connects the x-ray tube by cables from the tube housing.
- Provides the high-voltage necessary for x-ray production.
- Usually in X-ray room, or sometimes incorporated in control console

Control Console

- Located in the control booth
- Access point for the radiographer to determine the exposure factor and to actually initiate exposure.
- Equipped with buttons, switches, dials, of digital readouts

mA

- Allows the operator to set the milliamperage, the rate at which the x-rays are produced; determines focal spot point

kVp

- controls kilovoltage, and thereby the wavelength and penertrating power of the x-ray beam.

Fluoroscopy unit

- X-ray machine designed for direct viewing of the x-ray image.
- Permits the radiologist to view and record x-ray images in motion in real time. "Spot films"
- Radiologist usually activates this machine during examination

Tube movements

Longitudinal, transverse, vertical, rotation and angulation

Longitudinal

Tube is moved along the long axis of the table

Transverse

Tube is moved across the table, at right angles to to longitudinal

Vertical

Tube is moved up and down, increasing or decreasing the distance between the tube and the table

Rotation

Allows the entire tube support to turn on its axis, changing the direction in which the tube arm is extended

Roll (angulation)

(Tilt, angle) Permits the angulation of the tube along the longitudinal axis and allows the tube to be aimed at the wall rather than the table.