Radiology Final Exam

Inside the x-ray tube, electrons are made available at the ____, which has a negative charge.

Cathode

Inside the x-ray tube, electrons travel to the ___, which has a positive charge.

Anode

What does the focal spot refer to?

The location where electrons strike the anode.

What controls the number of electrons and, therefore, the number of x-rays produced as well as the amount of times those electrons/x-rays are available?

mAs

What controls the acceleration of electrons and determines the penetrating power of the x-rays produced?

kVp

Your leaded shielding and PPE are designed to protect you from what type of radiation exposure?

Secondary (Scatter)

What does the concept of ALARA refer to in radiology?

Practices and procedures which minimize radiation exposure in the practice setting.

What is the purpose of the dosimeter in radiology?

It detects the amount of x-ray exposure you receive over time when working in radiology in the clinical setting.

You always want to ____ the amount of time x-rays are emitted from the x-ray tube to reduce your exposure when working in radiology.

Minimize

When working in radiology, you should always ___ distance between yourself and the primary x-ray beam to reduce your exposure.

Maximize

What is the anode heel effect?

Variation in intensity (number) of x-rays in the primary x-ray field.

As the x-ray field size ___, the anode heel effect increases.

Increases

As the source to image distance (SID) ___, the anode heel effect increases.

Decreases

As the anode angle ___, the anode heel effect increases.

Decreases

What factor do we have no control over when trying to minimize the anode heel effect?

Anode angle

Anatomy of interest should remain ___ the tabletop and image receptor when imaging to reduce/prevent distortion artifacts.

As close as possible to

Anatomy of interest should be positioned ___ to the tabletop and image receptor when imaging to reduce/prevent distortion artifacts.

Parallel

What is magnification?

When anatomy is positioned further away from the tabletop/image receptor.

What is foreshortening?

When anatomy is not positioned parallel with the tabletop/ image receptor.

What is elongation?

When the anatomy is positioned close to and parallel with the tabletop/image receptor, but the center of collimation is not correct for the anatomy of interest.

What is an example of an intentional artifact?

A cast used to stabilize a fractured tibia is visible.

What structure is only visible when disease or abnormality is present?

Esophagus

What are the views you take to complete a standard 2-view of the thorax?

R Lateral and VD

What views will you take to complete the lung 3-view?

VD, L Lateral, and R Lateral

If you are evaluating the heart, which three views are required?

R Lateral, DV, and VD

What are the landmarks for collimation for a lateral thoracic view?

Cranial to the thoracic inlet to caudal to the xiphoid process.

Thoracic radiographs are taken at _____ to maximize visibility of structures in the radiograph.

Peak Inspiration

What would be an indication for imaging the thorax?

Coughing, difficulty breathing, and regurgitation.

What type of radiation are x-rays?

Electromagnetic Radiation

How do x-rays travel?

In straight lines

What is the purpose of the tube stand?

To support the x-ray tube.

What is the purpose of the collimator?

Restricts the size and shape of the x-ray beam

What is the purpose of the grid?

Absorb scatter radiation to improve the quality of the image.

What determines the grid ratio?

The height of the lead strips in the grid compared to the width of the space between them.

Does a more efficient grid have a higher or lower grid ratio?

Higher

What is the purpose of the Bucky?

Provides mobility for different sized patients.

Where is the x-ray beam most intense?

At the cathode side of the anode.

Why should technical errors be avoided?

To prevent the artifact of patient motion on radiographs.

Why should you always take thoracic films on peak inspiration?

Provides better visualization of structures.

What is the rule for radiation safety relating to Time?

Shortest

What is the rule for radiation safety relating to Distance?

Greatest

What is the rule for radiation safety relating to Shielding (PPE)?

Maximum

What does a crack or tear in PPE look like radiographically?

Appears black on film.

Where should the marker be placed for Lateral views?

Dorsal or ventral to the anatomy indicating the side closest to the image receptor.

Where should the marker be placed for VD/DV views?

Indicate the right or left side of the patient.

Where should the marker be placed for Craniocaudal/caudocranial/dorsopalmar/plantarodorsal/etc.?

On the lateral aspect of the limb indicating the right or left limb.

Where should the marker be placed for a lateral view of a bone or joint?

On the cranial aspect of the limb indicating right or left limb.

How do you properly position a radiographs on a screen for lateral views?

Point patient's head towards viewers left. Point patient's dorsal aspect towards the top of the view box.

How do you properly position radiographs on a screen for VD/DV views?

Point patient's head towards the top of the view box. The patient's left should be on the viewer's right.

How do you properly position radiographs on a screen for lateral views of bones or joints?

Point patient's head toward viewer's left. Point the patient's dorsal aspect towards the top of the view box.

How do you properly position radiographs on a screen for Craniocaudal/caudocranial/dorsopalmar/plantarodorsal/etc. views of bones or joints?

Point the proximal aspect of the limb towards the top of the view box. The patient's left should be on the viewer's right.

As tissue density increases, radiographic density

decreases

As tissue density increases, radiographic contrast

increases

Which of the following has the highest radiographic density?

Gas/air

Which of the following has the highest radiographic contrast?

Metal

If an object has low radiographic density and high radiographic contrast on the radiograph, that means that it will appear _______________ in the radiograph.

Bright/white

You take a radiographic view of the R lateral feline thorax. You evaluate the image. It appears too dark. The radiographic density of air is appropriate. You cannot see the structures of the thorax at all. Which of the following adjustments will you make?

Decrease the kVp

You take a radiographic view of the VD feline thorax. You evaluate the image. It appears too bright. The radiographic density of air is incorrect and appears gray. You can see the structures of the thorax though. Which of the following adjustments will you make?

Increase the mAs

Radiographic density is defined as _______________.

The brightness or darkness of a given area on the radiograph

Radiographic contrast is defined as _______________.

The difference in brightness or darkness between two different areas on the radiograph

Choose the answer which lists the 5 radiographic densities in order from HIGHEST to LOWEST radiographic density.

Air/Gas, Fat, Soft tissue/fluid, Bone, Metal

Which of the following is the formula for Sante's Rule?

(2 x tissue thickness in cm) + SID = kVp

The SID should always be ________ when calculating Sante's Rule.

40 inches

You add +2 kVp for every 1 cm increase in tissue thickness up to _______ kVp.

80

When you reach ______ on your technique chart, you should include the grid to create radiographs with adequate technique.

10 cm tissue thickness and higher

You add ___ kVp for every 1 cm increase in tissue thickness if your kVp is between 80 - 100.

+3

You add +4 kVp for every 1 cm increase in tissue thickness if kVp is _______.

100 and higher

When creating a thoracic technique chart, you determine your starting mAs by doing which of the following?

Take the starting mAs for your abdominal technique chart and divide by 2 (divide it in half).

When creating a technique chart for extremities and skull, you determine your starting mAs by doing which of the following?

Take the starting mAs for your abdominal technique chart and doubling it (multiply by 2).

If you are using the grid technique, where do you place the image receptor to take the radiograph?

In the bucky

If you are using the non-grid technique, where do you place the image receptor to take the radiograph?

On the tabletop

What is summation?

When parts of a patient or an object in different planes are superimposed. (Placed or laid over something else, typically so that both things are still evident)

Is the right or left kidney typically positioned more caudally?

The left is more caudal than the right kidney in both the cat and the dog. (left behind)

What is only visible if abnormal?

Gallbladder, adrenal glands, lymph nodes, pancreas, ureters, and urethra

Which abdominal structures can you see radiographically?

Diaphragm, liver, spleen, stomach, kidneys, small intestines, large intestines, bladder, uterus, ovaries, prostate glands, peritoneal cavity

Standard 2 - view

Lateral usually right
Ventrodorsal (VD)

Vomiting 3 - view

Right lateral
Left Lateral
Ventrodorsal (VD)

GDV 1 - view Gastric Dilation-volvulus

Left Lateral

Male Urinary Tract 3 - view

Lateral usually right
Lateral-flexed
Ventrodorsal (VD)

Why should you always take abdominal films on peak expiration?

it allows the diaphragm to relax which maximizes the separation of soft tissue structure for improved visualization

Know which structures are not visible on an abdominal radiograph unless it is abnormal.

Gallbladder, adrenal glands, lymph nodes, pancreas, ureters, and urethra

When might you use the alternative views for imaging the abdomen/thorax?

When the patient is in respiratory distress or has labored breathing. Or when clinical signs suggest free fluid or free air in thoracic cavity

What are the two alternative views?

Lateral view with a horizontal beam
Lateral Decubitus View

What technical error will occur if the patient is not fasted prior to taking abdominal radiographs?

Food and Feces will be present

What are the indications for taking radiographs of bones and joints?

Trauma, pain, and lameness

Which bones and joints are best imaged with the patient in dorsal recumbency?

Scapula, scapulohumeral joint, humerus

Which bones and joints are best imaged with the patient in sternal recumbency?

Elbow, radius, ulna, carpus, metacarpals, phalanges

How do you position the patient for imaging the pelvis in a standard 2-view study?

Ventrodorsal extended and right lateral

What are the landmarks, in general, for collimation, measuring, and centering for each of the following?
Lone bone:

Measuring: middle of diaphysis
Centering: middle of diaphysis
Collimation: include the joint proximally and the joint distally

What are the landmarks, in general, for collimation, measuring, and centering for each of the following?
Joint:

Measuring: Center of the joint
Centering: Center of the joint
Collimation: include the distal potion of the bone proximally and the proximal portion of the bone distally

Standard 2 - view: Pelvis

Ventrodorsal extended view
Right lateral

Trauma 2 - View: Pelvis

Ventrodorsal frog-leg
Right lateral

Why are radiographs submitted to PennHIP and OFA?

To identify the signs of hip dysplasia

Which of these has greater predictive power?

PennHIP

Be able to tell me some of the hallmark signs to look for radiographically for identifying a patient with hip dysplasia.

· Shallow acetabulum
· Flattened femoral head/deformity
· Secondary degenerative joint changes such as thickening or remodeling of the femoral neck, sclerosis of the acetabulum (dorsocranial margin)
· Luxation or subluxation of the femoral head (displacement)
· Increase in joint space width

What is the most easily recognized radiographic abnormality?

Fractures!

Where should you pack the Play-Doh on the foot?

In the sulcus

What is the purpose of packing the Play-Doh in this location?

You want to make it even with the rest of the sole so it isn't trapping air

Before taking images, how will you position the horse's foot?

On wooden blocks. You want to make it parallel with the block and to the ground

What are the views that complete this study? Distal Phalanx:

Lateral view of P3
▪ Beam to be halfway between heel and toe and halfway from coronary band and ground surface