Imaging Modalities- Chapter 6 Washington Leaver Flashcards
What are the (3) ionizing radiation image procedures we use
Conventional radiography
Computed tomography (CT)
Nuclear Medicine (bone scans)
Positron Emmision Tomography (PET)
Non ionizing image procedures/techniques
Magnetic Resonance Imaging (MRI)
Ultrasonography
Filling defects, channels that are not completely visible or that appear frothy can demonstrate the presence of pathological changes
Lymphangiograpy
(provides useful information for treatment field design)
Uses specific dyes or contrast injected into lymphatic
Provides two-dimensional image of the interior body (images produced because of differences in body density)
Conventional and Digital Radiography
What imaging modalities look like slices of the body?
CT- computed tomography (virtual or 3D)
each slice seconds
multiple slice machine takes 64-128 slices at time
images have 10 to 20 times the detail of conventional
Detects more metastatic disease than primary tumor
Nuclear Medicine- Isotope
What allows tracking of a “moving tumor”
Four dimensional CT
Ex; Lung tumor hidden while breathing
PET- Positron Emission Tomography
Gamma Rays
What image modality can demonstrate function rather than structure?
PET- Positron Emission Tomography
Ex; cancer cells absorb sugar isotopes more quickly than normal cells
Radioisotopes used for diagnosis and treatment
Provides information physiology and anatomic structure
Nuclear Medicine
Short lived isotopes injected into the body
Nuclear Medicine
This image can be static or moving
Ultrasound
Ultrasound advantages
- No exposure to ionizing radiation
- Noninvasive and painless
- Requires no contrast media
Disadvantages of Ultrasound
Does not penetrate bone or air-filled spaces effectively
Magnetic Resonance Imaging (MRI)
- resulting image looks like a CT image
- provides information about chemicals
- uses no ionizing radiation
What are the advantages of using PET and CT together
allows visualization of small lesions
retains spatial accuracy of CT
What types of fields does MRI use for imaging
magnetic files and radio waves
What type of fields does Ultrasongraphy use
echoed sound waves
Disadvantages of an MRI
- Expensive shielding required
- More expensive than CT
- Low patient throughout
Ultrasound
- Uses high frequency sound waves
- transducer generates high frequency sound waves
- transducer is moved over the body part being examined
- transducer picks up returning sound waves
MRI properties
- hydrogen nuclei
- magnetic field applied; nuclei and patient pulsed with radio waves
- nuclei sends out a weak radio wave and an image is formed
