Radiography general info Flashcards
PA stands for? Where does the beam start and end?
Posterior-Anterior. Beam goes through posterior and exits anterior to image receptor.
How far is AP and PA from image receptor?
AP=10 inches away from image receptor, adds 10% magnification
PA=6 inches away from image receptor, better quality image than AP
When to use AP instead of PA?
AP is used when the PT cannot come to the X-ray dept and needs a portable xray. Not as good quality image as PA.
What position is a lateral X-ray compared to AP or PA?
90 degrees to PA or AP, while standing with left or right side to image receptor
Define decubitus
Recumbent (laying) with horizontal beam
Define lateral decubitus and when used
PT laying on right or left side with image receptor to back.
Right Lateral Decubitus looks like PA, left lateral decubitus looks like AP.
Used to determine air/fluid levels.
What is Dorsal Decubitus?
Laying on back with image receptor to right side.
Looks like lateral X-ray.
What is an oblique projection? When used?
Half-way between PA/AP and lateral.
Extremities usually require three projections and use oblique.
Define radiology
Imaging technique that uses ionizing radiation to view internal structures of body in static or dynamic mode
What are the two classifications of ionizing radiation
- Particulate and Electromagnetic
2. X-Ray
What is X-Ray?
Bundles of electromagnetic energy, produced in a cathode tube, with sufficient energy to ionize matter. 99% is heat, 1% are photons.
What four things are needed for production of X-Ray?
- Source of electrons
- Way to accelerate them (current)
- Way to stop them (anode)
- Vacuum in envelope to prevent interaction
X-ray interaction with matter
Tissues absorb radiation differently. Denser the tissue the harder for X-ray to penetrate.
Air shows up black as does not absorb X-ray. Bones appear white by absorbing radiation.
What color does air appear as on an X-ray? Why?
Appears black as air does not absorb X-ray photons.
What color does bone appear on X-ray? Why?
Bone appears white as they absorb radiation.
What do high energy photons do to body and how do they appear on xray?
Don’t interact with body and go straight through. Appear really black on X-ray.
AP stands for? Where does the beam start and stop?
Anterior-Posterior. Beam goes through anterior and exits posterior.
Compton Scatter is common in what type of X-ray?
Fluoroscopy
What are the effects of radiation on body?
- Cumulative over lifetime
- Produces free radicals
- Organs have different sensitivities but those with rapidly dividing cells are more sensitive (ex: lymphocytes, reproductive cells, erythrocytes)
Fluoroscopy is what kind of study?
Functional
What does fluoroscopy dynamic imaging look for?
Functional health
BAE=Can look at intestines for inflammation or polyps
UGI=pyloric stenosis, reflux
Modified swallows= Measures muscle pressure and movement, coordination, and strength of esophagus
Average background radiation
2.4 millisievers
What is the radiation exposure during fluoroscopy?
Typical: 1-3 R/min
Max: 10 R/min
Alarm sounds at 5 minutes
How to protect against radiation exposure?
- Lead apron (0.25mm Pb/eq) reduces 99% of radiation
- 6 feet away
- Highest energy scatter
- 90 degree angle to beam
- ALARA (as low as reasonably achievable)
- Shield patient’s parts not involved
Things to consider about patient
Age, pregnancy, portable, difficult exam, upright vs flat (upright shows air/fluid levels, if PT can’t do upright then order decubitus), what ruling out
Which X-ray to test for free air under diaphragm?
Upright abdomen or upright chest x-ray. Want to view apicies to costophrenic angles.
Interventional Radiography Fluoroscopy set up like and can do what?
Set up like mini OR suite. Can place stents, PIC lines, central catheters, fix bleeds, or aneurysm clips
Supine?
On back
Prone?
On belly/stomach
Recumbent
Laying back
Trendelenberg
Head down, feet up
Why upright done instead of recumbent?
Upright shows air/fluid levels
Is X-ray needed for upper respiratory infection?
Not indicated unless hear something
Does hemoptysis (spitting up blood) need an X-ray?
Yes. Start with a chest X-ray (CXR) and then a CT if the CXR is normal
Does hypertension (high blood pressure) require an X-ray?
Yes. Get a chest X-ray (CXR) to determine cardiac size.
What do you count in a chest X-ray? What are the tiny dots?
Count ribs to 9th or 10th rib and visualize the lungs. Tiny dots are the pulmonary vessels.
What two things should a good lateral X-ray show?
- Spine
2. Pulmonary effusions
What to look for in shoulder pain?
Look for degenerative changes, changes to A-C joints, bursitis
When to image hip pain and what might find?
Only in persistent pain. Possibly avascular necrosis.
When to order X-ray with lumbar pain and what might find?
Degenerative changes. Order MRI is pain persistent.
Which X-rays for acute abdominal pain?
Begin with flat and upright
Which imaging for difficulty in swallowing?
BAS (barium swallow)
Which imaging for ulcer?
UGI (upper gastric)
Which image for lump in breast?
Mammography
Which image for aspirated foreign body?
Lateral soft tissue of neck. Object may be radiolucent which then requires esophageal studies.
Which imaging for ingested foreign bodies?
Images of neck, chest, and abdomen. Coins most common.
Geometric properties vs Photographic properties
Geometric= sharpness (distortion and recorded detail)
Photographic= Visibility (density and contrast)
What are photographic qualities?
Being able to distinguish structures from one another, too light or dark, missing something is not penetrated enough
What are the 4 geometric qualities?
1 Distortion (wrong size/shape of image), 2 Magnification (lose detail with more), 3 Elongation (size), 4 Foreshortening (shape) (DMEF)
Normal magnification
All images on radiograph are larger than actual. Normal magnification is between 1.05 and 1.1.
Elongation occurs when…?
Occurs when tube or image receptor are improperly aligned
What is foreshortening?
Part being imaged isn’t lined up with image receptor and causes distortion. Can be useful to open disc spaces or move overlying anatomy.
Lateral decubitus can be confused with what other view?
AP view if rotated
Dense tissue is hard or easy for X-ray to penetrate?
Hard.
In chest x-rays what does the RIP acronym stand for?
R=Rotation
I=Inspiration
P=Penetration
How do you assess rotation in a chest x-ray?
Look at the sternal head of the clavicles and make sure they are symmetrical.
What do you look for when assessing inspiration of chest xrays?
Try to count 10 ribs to know if inspiration is good. 9 ribs is OK but not less. Defined as being able to see/count ≥10 ribs.
What do you look for when assessing penetration of chest xrays?
Should barely able to see intervetebral discs through the heart/upper mediastinum. If can see discs too clearly then this is overpenetration, if can’t see discs at all then underpenetrated.
In a PA chest xray what order of things do you check?
RIP, extrathoracic structures, ribs, pleura, diaphragms, heart, hila, lung parenchuma (apicies, middle, bases, lingula)
In a lateral chest xray what should you be checking?
Extrathoracic structures, sternum (manubrium, body, xiphoid), ribs (posterior and anterior), spine (foramina, vetebral bodies, joint spaces), diaphrahm (double bubble with liver on right), heart, supracardiac spaces, infracardiac space (posterior triangle)
What is an infiltrate?
Something inside of lung, usually fluid. Can be caused by many things including pneumonia and CHF.
What is an effusion?
Something between lung and chest wall. Not in the lung itself but can press on lung.
Infiltrate vs effusion
Infiltrate in in the lung while effusion is outside of lung and inside chest wall
Where is the lingula?
Left upper lung. Combined term for the two bronchopulmonary segments.
What is radiopacity mean?
Whiteness. Increased density.
What does radiolucency mean?
Blackness. Decreased density.
What does infiltrate mean?
A collection of something (usually liquid) within tissue or within space
What does effusion mean?
A collection of something (usually liquid) outside a tissue or within a potential space
What does mass mean?
Something solid that is generally well marginated and doesn’t belong there
What does lesion mean?
Something poorly marginated that doesn’t belong there
Mass Vs Lesion?
Mass is well marginates, lesion is not well marginated
What are the three types of radiopacity patterns?
Alveolar pattern, Interstitial pattern, Vascular pattern (AIV)
What does an alveolar pattern look like?
Fluffy, soft, poor demarcated opacifications
What does an interstitial pattern look like?
Looks like lace. Branches of lines radiating toward periphery of lungs. Consolidation of interstitial fluid.
What does a vascular pattern look like on chest xray?
Increase in size of pulmonary arteries as extend into lung (pulmonary hypertension), or a decrease in size (embolus), or lack of vascular marking in periphery (pneumothorax)
What are the 4 possible causes of an alveolar pattern?
1 Pulmonary edema, 2 viral pneumonia, 3 pneumocystis, 4 alveolar cell carcinoma
What does an interstitial pattern look like?
Looks like branching lines radiating toward the periphery of the lungs
What are the 2 possible causes of an interstitial pattern?
1 Interstitial pneumonitis, 2 pulmonary fibrosis
The diaphragm is higher on the right side because of what?
Liver pushes it up
If image is overpenetrated then it appears…..
Too clear, can see vertebra too easily, air (black areas) shows up a lot
If you cannot see the heart border on a chest xray then it’s likely an infiltrate of what area?
If cannot see heart border then likely lingular infiltrate. A lower lobe infiltrate usually lets you see the heart.
What is atelectasis?
Lost of lung volume and loss of air
What would atelectasis look like on an xray?
A density a lobe or segment. Compensatory hyperinflation of unaffected lungs. Causes a significant loss of volume.
What happens to trapped air during atelectasis?
Gets absorbed from pulmonary circulation
What are the findings in congestive heart failure?
Increased heart size. Large hila with indistinct borders, fluid in interlobar fissures, pleural effusions and alveolar edema (Bat’s wings), interstitial edema (Kerley B Lines), dialated upper vessels
What are Kerley B Lines?
Little dashes near costophrenic angle. Pathneumonic for heart failure.
What does a tension pneumothorax look like?
Corocoid process sticking out. Pleura is gone, only seeing air and no water or fat.
What does a pleural effusion look like?
Cannot clearly see heart which implies a problem in the lingular part of lung. Cannot see CFA. If can’t see “double bubble” then bad.
Overpenetration will cause
underinterpreting/missing a finding
If something is very radiopaque then what is it’s radiolucency?
Not very radiolucent
Black on an xray is what for radiopaque and radiolucent?
Black is least radiopaque and the most radiolucent
White on an xray is what radiopaque and radiolucent?
White is most radiopaque and the least radiolucent
Underpenetration appears as ____ while overpenetration appears as ____
Under is lighter, over is darker
On a lateral chest xray where should you look for find bad things hiding?
Retrocardiac space
An underpenetrated xray would cause you to do what with a diagnosis?
Underpenetrated would cause you to over diagnose
If you can see discs very clearly then film is likely….?
Overpenetrated
If you can’t see discs at all then film is likely…?
Underpenetrated
Where does the ascending color turn?
Hepatic flexure
What are the layers of skin and organs in the RUQ?
Skin, muscle, liver, gall bladder, pancreas top to bottom in RUQ
Why is the pancreas filled with “evil spirits”?
Evil spirits live in the pancreas. Endocrine, excocrine, partly retroperotoneal and partly intraperotoneal. Can autodigest. All messed up.
What can gallstones do to the pancreas?
Gall stones can be pushed into common bile duct and cause pancreas to back up and autodigest.
Retroperitoneal organs can cause pain located where?
Back pain
Intraperitoneal organs can cause pain where?
Abdominal
The pancreas is in which peritonium and causes pain where??
Both retro and intraperitoneal and can cause pain in both back and abdomen
KUB includes from where to where?
KUB-includes diaphragm to top of pubic symphyis
What structures cross the midline?
Stomach, transverse colon, small bowel, aorta, IVC, urinary bladder, uterus
If you can see the psoas muscle on a KUB what does it mean for fluid accumulation?
Unlikely to have fluid accumulation
What is under the liver?
Gall bladder
Gas patterns in the jejunum look like what shape?
Wavy
Gas patterns in the ileum look like what shape?
Rectangle
Gas patterns in the colon look like what shape?
Semicircular
Large bowel obstruction can be caused by what?
Tumor, abscess, diverticular disease, volvulus
What can cause a small bowel obstruction?
Adhesions, hernia, tumor, gallstones
What is the name of large bowel mucosal folds and shape?
Haustral folds, semicircular
What is the name of small bowel mucosal folds and shape?
Valvulae conniventes, circular folds
CT vs MRI
MRI=soft tissues which have water (muscles/tendons/ligaments), or soft jello-like organs like the brain use MRI.
CT=for things without water (chest, abdomen, pelvis, bone). CT in acute patients, MRI for subacute
Is CT or MRI better for bone lesions and bone fractures?
CT is better
MR of the musculoskeletel system can see the following structures:
Soft tissues: Fat, muscles, tendons, ligaments, nerves, blood vessels, and bone marrow (p. 1078 of lab & diag test book)
What is the most frequently used MRI contract and what route is it delivered? What excretes it?
IV Gadolinium. Kidneys. Be care in PTs with kidney disease.
What is the relationship between tissues that contain a lot of hydrogen and those that contain little hydrogen and how they show up on MRI?
Tissues that contain very little hydrogen, such as cortical bone, flowing blood, and an air-filled lung, generate little or no MR signal and appear black on the images produced. Tissues high in hydrogen, such as fat or carti- lage, have high signal intensity and appear white.
On an MRI if a tissue has very little hydrogen what color would is appear as?
Black
On an MRI if a tissue has a lot of hydrogen what color does it appear as?
White
What sort of tissues are high and low in hydrogen?
Little hydrogen=cortical bone, flowing blood, and an air-filled lung; High hydrogen=such as fat or cartilage
What is a Telsa with regard to MRI?
Strength of the magnet. 1 T equals 10,000 G.
What rays does nuclear imaging use?
Gamma rays
A nuclear imaging HIDA scan look at what organ?
Gall bladder
What is the most frequent type of nuclear imaging study?
Gastric emptying.
When would you order a nuclear imaging Lung Scan instead of a CTA?
Used for pregnant, dialysis, or PTs with allergy to IV contrast. Otherwise get CTA.
The amount of isotope giving in a nuclear imagine myocardial perfusion test is based on the PT’s what?
Age
After a nuclear imaging perfusion scan where isotype was given what should the PT be told to do?
Drink lots of water
What does “Photopenic” mean when doing a nuclear imaging Myocardial Perfusion Scan?
No uptake of the isotope due to infarcted tissue.
A PET scan is a nuclear imaging study but is doesn’t use which ray?
Gamma
A PET Cardiac scan is good for someone with a high…?
BMI, but uncommon and very expensive
What must a patient do in the hours leading up to a PET/CT scan?
No exercise for 24 hours, NPO for 4 hours, stay warm, and might be told to eat a fatty meal the night before. Don’t want to screw up glucose uptake.
In a PET/CT scan what must the PT’s glucose be under?
Under 200, some places it must be under 150
After a PET/CT scan a PT is told to avoid what two things for the first 24 hours because they are radioactive?
Avoid holding baby, avoid breastfeeding
Why does the brain appear very dark on a PET/CT scan?
Brain uses a LOT of glucose and PET/CT traces glucose uptake
If a PET/CT scan shows a tumor but no glucose uptake what might it mean about the tumor?
Might mean the tumor is benign. No glucose update=not active
If a PET/CT scan shows a and but there is a lot of glucose uptake what might it mean about the tumor?
Means tumor is actively metabolizing glucose and need to do a biopsy of the tumor
A nuclear imaging Bone Scan tests for what two things about a bone?
Blood flow to the bone, function of the bone
In a nuclear imaging bone scan what is the uptake like in kids compared to adults?
Lots of uptake in kids who are still growing, little update in adults who are not growing
What are some PT restrictions BEFORE thyroid treatment using nuclear medicine?
Low iodine diet for 2-4 weeks, no iodine contrast for 6 weeks before, stop antithyroid meds, CANNOT BE PREGNANT before or 6 months after, no betadine/vitamins/supplements/cough meds for 2-4 weeks
What are some PT restrictions AFTER thyroid treatment using nuclear medicine?
No pregnancy for 6 months! Flush 3x after use, sleep along, wash hands a lot, no sex or kissing, dont cook for others, replace toothbrush after 1 week, drink extra water and use lemon drops to stimulate saliva
Nuclear Medicine imaging isn’t checking anatomy but is instead checking….?
Function
Nuclear Medicine can not only determine the function of an organ but what else can it do that is non-diagnostic?
Treatment of many cancers and hyperfunctioning tissues
