Course 111 - Diagnostic Imaging II - 5.1 - Fixed Rad/Fluoro X-Ray System

Dosimeter

Device that measures exposure to ionizing radiation

How is a generator cabinet cooled

Oil or gel

Bucky

A tray in the table or wall stand that holds a Computed Radiography plate or portable digital detector

Wall stand (vertical stand)

A vertical container for a filter and CR cassette or digital detector, most move vertically and some move horizontally

Field of View (FOV)

Part of the patient’s anatomy that is displayed in the image

Grid

A plate, typically used in the bucky, that absorbs scatter radiation

Imaging stitching

Computer formatting that allows multiple shots to be combined to show one larger anatomical region

Artifacts

Any item that obscures the desired information on a radiographic image

In the tube head, why is there a delay between pressing the exposure button and the release of ionizing radiation?

• Heating the filament

• Rotating anode to proper speed

Main components of a fixed x-ray system

• Tube head

• Table

• Wall stand

• Generator cabinet

• Control/viewing station

Chest room

X-ray rooms with only a wall stand, but no table

Fixed Rad X-ray unit safety feature

Will not allow X-rays to be released if the tube head is not centered over detector selected, whether fixed or bucky system

Uses for fixed Rad diagnostic X-ray images:

• Bone fractures

• Tumors and abnormal masses

• Pneumonia

• Calcification

• Foreign objects

• Dental problems

In Rad. X-ray systems, the quality of the image can be directly correlated to the ___ during the time needed to take the image

Patient’s ability to be still

Why are patients provided gowns for exposure?

Minimizes possibility of metallic items on clothing (zippers, snaps, buttons, bra wires and fasteners) showing up as artifacts

Purpose of a grid

Used to eliminate X-ray scatter from blurring the contrast in the image

Benefits of grouping radiology services in one physical location:

• Easier shielding

• Consolidate high voltage wiring

• Planning where structure can support weight, such as ground floor

Safety concerns for fixed Rad X-ray units:

• Ionizing radiation

• High voltage/current

• Heavy weight

Radiation Absorbed Dose (RAD)

The amount of radiation received in units of heat energy

Contrast agents

Substances that temporarily change the way X-rays interact with the body

How are contrast agents administered?

• Consuming

• Via enema

• Blood vessel injection

Image intensifier

Vacuum tube designed to amplify the brightness of the fluoroscopic image

Brightness gain

The amount an image intensifier can amplify the light intensity of an image

Charged Coupled Device (CCD)

A flat light-sensing device using silicon as the active component

Fixed fluoro. system parts:

• X-ray source

• Fluorescent screen

• Image intensifier (II)

• Camera

• Control/viewing station

Image intensifier (II) components

• Input window

• Input phosphor layer

• Photocathode layer

• Output window

• Output phosphor layer

Magnification brightness factor of Image intensifier (II)

5,000 to 20,000 times its original value

Types of fixed fluoroscopy machines:

• Tubes mounted under table with II/detector mounted over table, vice versa

• C-arm system

Types of Fluoroscopy X-ray detectors:

• Image intensifier (II)

• Flat Panel Detector (FPD)

Image intensifier (II) is shown in approximately ___

30 FPS

Flat Panel Detector (FPD) provides ___ in ___

60 FPS, full resolution

Modes for fluoroscopy

• Pulsed

• Continuous

What occurs when removing grid from fluoroscopy systems?

Reduces radiation dose by >50% without degrading image quality

Patients not fit for fluoroscopy procedure

• Pregnant patients

• Existing kidney problems/failure

• Allergic to contrast dye

• Recently had barium x-ray procedure

What should be ensured when installing fixed fluoroscopy x-ray system for a facility?

• Dedicated power source

• Electrical pathways that maximize movement of people/equipment in X-ray room

• HVAC system

• Floor structure to handle weight

• Shielding

Who mandated all continuous fluoroscopy units to be equipped with a timer?

Food and Drug Association

Joint Commission

Audits and incorporates new standards for fluoroscopy systems

X-ray system displays images that possess

Significant density difference