rad 101 quick review
Radiographer: administers ionizing radiation
ASRT- practice standards: includes clinical performance standards, quality performance standards, and professional performance standards
ARRT: ethics- code of ethics 10 statements(behavioral guide) and 22 rules of ethics
Hand hygiene!
Wear surgical mask if performing lumbar punctures
Rad tech must obtain patient clinical history
-verify correct procedure ordered
-observe any abnormality to report to radiologist
Involuntary motion- use shorter exposure time
Voluntary motion- explain procedure, make patient comfortable, use support devices, and if needed shorted exposure time
4 types of IRs
PSP plate used in CR
Cassette with film rarely used
Solid state digital detector- now used in DR
fluoroscopic image receptor
Technique charts should be in every room and on mobile machines, it should specify projections performed in room and exposure factors for each projection
Primary factors must be taken into account to establish correct foundation technique for each unit:
mAs
kVp
AEC
SID
Relative patient or partial thickness
Grid
CR/DR exposure indicators
IR or collimated field dimensions
Electrical supply characteristics
Gonad shielding : when gonads lie within 5cm from the primary x ray field despite proper beam limitation
And only do so if anatomy of image is not obstructed
IR positions : lengthwise, crosswise, and diagonal
Most used is lengthwise
(Name is based on the relation to the long axis of the body)
CR IS ALWAYS CENTERED TO IR (unless displacement is being used)
CR should be perpendicular to the part and IR to minimize distortion
Main reasons to angle the CR:
Prevent structures from overlapping
Make curved anatomy look straighter
Line up with tilted/angled joints
Reduce image distortion
SID affects magnification,spatial resolution, and patient dose
Longer SID reduces magnification
Exposure field must be restricted to only include anatomy of interest
Collimation minimizes patient exposure and reduces scatter radiation
Shuttering is aesthetics only, not trying to cover up over radiating a patient
R and L markers are mandatory
Shouldn’t obscure anatomy
Should be placed in exposure field placed outside of lead shielding
Each radiographer must evaluate each radiograph and determine: acceptability of image features, proper radiation safety practices, objectives have been met, presence of marker, proper collimation, patient identification,evidence of required shielding, absence of artifacts
Radiographs are viewed in anatomical position except for hands, wrists, feet, toes
Required on images: marker, date, patients name, and institution identity
BMI 30-39.9 is obese
Above 40 is morbidly obese
Pubic symphysis can be located on patient using jugular notch by height
<5ft: 21 inches
5ft-6ft: 22 inches
>6ft: 24 inches
High kVp= more scatter
More energetic X-rays create greater scatter within the patient's body, which can cause a "foggy" effect on the image
but higher kVp also reduces patient exposure and increases image quality
What higher kVp DOES improve
✅ Penetration
Higher kVp gives x-rays more energy, so they pass through anatomy easier.
Benefits:
anatomy is penetrated better
fewer repeat exams
can see through thicker body parts
more grayscale visibility
So the image can look:
more “smooth”
more penetrated
less underexposed
What higher kVp DOES worsen
❌ Scatter radiation
More energetic photons also:
bounce around more inside the patient
create more scatter
Scatter reaching the IR causes:
foggy appearance
lower contrast
loss of detail
So why use high kVp at all?
Because radiography is balancing:
penetration
contrast
patient dose
scatter
That’s why we use:
✅ collimation
✅ grids
✅ proper exposure factors
to control the scatter created by higher kVp.
I need engraved into my head that the 3 major things affected by kVp is magnification, spatial resolution, and patient dose
Long SID= less size distortion
Collimation affect patient dose and scatter radiation