8. Medical Imaging equipment(2)

X-ray Tube

A device made from Pyrex glass located inside lead-lined housing containing an anode and cathode, used to produce X-rays.

The primary components of a tube are

anode and cathode

The filament allows for

Thermionic emission

Primary beam

The beam of photons leaving the tube before interacting with the patient

Collimator

A beam-limiting device that controls the size and shape of the x-ray beam.

Increasing collimation

Decreases field size

Decreasing collimation

Decreases beam limitation

Positive Beam Limitation (PBL)

A feature that detects the size of the cassette and automatically limits the light field to that size.

Angulator

(Goniometer) is the front of the tube housing

Radiographic Table

A table that can be tilting or non-tilting, with a radiolucent tabletop that holds the patient for imaging.

Bucky Mechanism

A mechanism located beneath the tabletop that holds the cassette (IR) and blurs out grid lines during exposure.

Control Console

5 main controls for power, kV, mA, timer, and rotor-exposure switch, used for setting imaging parameters.

Technique

Kv, mA and time

Kilovoltage (kV)

determines the penetrability of the x-ray beam.

Milliampere-seconds (mAs)

Indicates the amount of current supplied to the x-ray tube, calculated as mA multiplied by time in seconds.

At 50-400 mA

Most routine diagnostic radiography is done

Fluoroscopic mA

Is Typically between 0.5 to 5

Exposure Switch

A two-step switch used to initiate x-ray exposure, with prep and exposure functions.

Rotor portion

(Prep) switch causes the anode to rotate and causes The filament to heat up, 1 - 2 seconds

Tube Movement

Movements of the x-ray tube including longitudinal, transverse, vertical and angulation to position for imaging.

Longitudinal

Moves the tube to the pts head or feet, to the techs right or left. Use this movement to “line up your Bucky”

Transverse

Move the tube toward or away from the tech, right or left over patient.

Vertical

Moves the tube up or down

Tube angulation

(Roll) pivots the tube at the point where it is attached to its support, used to angle the tube or cephalic

Cassette holder

A wall mounted cassette holder, simply holds cassette for standing patients, do not contain a grid

Wall Bucky

Wall-mounted book contains a grid, works the same as the table Bucky a bucket always contains a grid

CR (Computed radiography)

Uses an image plate inside of a cassette that is placed in the bookie or directly on the table top

Digital Radiography (DR)

A type of radiography that uses permanently fixed panels or wireless detectors without cassettes.

2 sizes for cr

10 x 12 and 14 x 17.

Cassette Orientation

The placement of cassettes within the bucky/cassette holder in either 'landscape' or 'portrait' mode.