The device that recieves the energy of the x-ray beam and forms the image of the body part.
5 types of IR's
Cassette with film, Image Plate (IP), Direct Radiography(DR), Portable Digital Radiography, Fluoroscopic Screen
Define optical density. What is its primary controlling factor?
Degree of blackening when associated with radiologic film and as brightness when describing appearance. mAs
What is brightness?
Its the digital imaging term equivalent to OD.
Define contrast. What is its primary controlling factor?
The difference in density between any two areas on a radiography. kVp
What is recorded detail?
The ability to visualize small structures.
Distortion
The misrepresentation of the size or shape of any atomic figure
What is magnification? What is its primary controlling factor(s)?
A type of distortion in which the image is larger than the actual object(present in every radiograph). OID and SID
Superimposition
The relationship of the anatomic superimposition to size, shape, position, and angulation must be reviewed.
Adjacent Structures
Each anatomical structure must be compared with adjacent structures and reviewed to ensure that the structure is present and properly showen.
What factors affect mAs in digital imaging?
Visible OD, Image Noise, and Patient Dose.
What exposure factor controls radiographic contrast?
kVp
A long scale has what kind of contrast?
low contrast
What are the 6 factors that control recorded detail?
IP phosphor (digital), Screen, Motion, Distance, Geometry, and Focal Spot Size
True or False: All radiographs yield some degree of magnification.
True, because all body parts are 3 dimensional.
What are the 5 factors that control or affect shape distortion?
Alignment, Angulation, Central Ray (CR), IR, and Anatomical Part.
Describe how a posteroanterior (PA) projection radiograph of the chest should be displayed on a viewing device.
Patient standing erect in anatomic position, as if face to face with the viewer.
How should lateral projections be displayed?
Hung from the perspective of the X-ray tube.
Disinfectant:
Chemical substance that kills pathogenic bacteria(not their spores).
Antiseptic:
A chemical substance that inhibits the growth of pathogenic organisms without necessarily killing them.
Sterilization:
The destruction of all microorganisms.
Disinfection:
Process of killing all pathogenic organisms.
What information should be included in a procedures(or protocol) book that identifies each examination performed in the radiography department?
An outline of the procedure , the # of staff required, duties of each memeber of the team, and a listing of the required sterile and nonsterile items.
Types of involuntary muscle tissue
Smooth(peristalisis) and Cardiac
Perstalisis
The rhythmic motion of smooth muscle structures.
What are 5 ways voluntary motion can be controlled?
apply immobilization, give clear instructions, adjust support devices, decrease exposure time, and provide patient comfort.
What is the minumum number of personnel that should be used to transfer a patient?
four
What are the four items of identification that should be on every radiograph?
Patients Name, Date of Exam, Institutional Identity, and Side Marker(L or R)
What adjustment can be made by the radiographer to compensate for an increase in OID?
Increase the SIID
List four reasons why it would become necessary to angle the CR?
To avoid the superimposition of underlying structures
To aoid staccking a curved structure on itself
To project through angled joints
To project through angled structures without foreshortening or elongation.
How is radiographic contrast affected when the radiation beam is restricted to only the area under examination? Explain why?
Radiologic contrast is increased because scatter radiation is reduced thereby producing a shorter scale of contrast.
When using film/screen cassettes or computed radiography imaging plates, how is the field size limited to prevent overexposing the patient?
The automatic collimator automatically adjusts to the size of the IR. (automatic collatmators do not allow the field size to be larger than the IR)
True or False: In a direct digital imaging, the field size or collimation must be manually adjusted.
True
True or False: Shuttering of direct digital images is an acceptable substitution for proper collimation.
False. Shuttering only gives the displayed image the appearance of proper collimation and does not protect the patient from unnecessary radiation exposure. (the use of shuttering in place of propper collimation is a violation of the ASRT Code of Ethics.
Give 3 guidelines for determining when gonadal shielding should be used.
When gonads are in close approximity to the primary x-ray field(about 5 cm)
When the clinical objective of the exam is not compromised
When the patient has a reasonable reproductive potential.
AEC:
Automatic Exposure Control
ASRT:
Americal Society of Radiologic Technologists
CCD:
Charge-Coupled Device
Which factor controls radiologic contrast?
kVP
What controls shape distortion?
Alignment
What change in exposure factor should be used to control voluntary motion that is a result of the patient's age or mental illness?
Decrease the exposure time.
What procedure best reduces the possibility of patient-controlled motion?
Give understandable instructions.
What is the primary purpose of collimation?
To reduce patient exposure
How is a radiologic image quality affected when the radiation beam is restricted to the area under examination only?
Increased contrast
Which change will most improve recorded detail when the sternum is imaged?
Collimating from a 14x17 inch field size to the area of interest only
What is the image receptor in direct digital radiography?
Solid-state detector or charge-coupled device
What are 2 reasons to avoid electronic side markers in a digital image?
Increased potential for errors in marking the correct side.
