Imaging

Question 1

Importance of Radiology

Answer 1

Uses medical imaging technology to non-invasively diagnose and guide treatment of medical conditions

Question 2

Imaging modalities

Answer 2

Radiography 
Computed Tomography
Nuclear Medicine
Ultrasounds
Magnetic Resonance

Question 3

Radiation

Answer 3

Energy traveling through space or matter
EM radiation: x rays from atomic shells, gamma rays from nucleus
Particulates: charged and uncharge particles

Question 4

Projection Imaging

Answer 4

Generate Xrays
Detect transmitted Xrays
Use radiopaque contrast media to visualize structures

Question 5

Flouroscopy

Answer 5

Real time imaging
Interventional procedure
Concerns about skin dose of radiation

Question 6

X ray detection

Answer 6

Film measures density

The more dense the whiter it is

Question 7

Benefits and Drawbacks of Radiography

Answer 7

Low dose radiation
Simple, fast, inexpensive
High resolution
Need multiple projections
Limited number of views
Cant see 3d

Question 8

Computed Tomography

Answer 8

Xray source rotates around patient taking multiple shots
Can see in 3D
Table can move during tube rotation for whole body scan

Question 9

Helical or Spiral CT

Answer 9

Table moves while Xray tube rotates with no loss of information

Question 10

Multiple Detector CT

Answer 10

Multiple images per one rotation of tube
Fast
Good for ER
Better Quality
Good for Cardiac

Question 11

CT benefits and drawbacks

Answer 11

Fast scanning
3D
Good contrast, High Res
No need for exploratory surgery
Bad soft tissue contrast
Higher radiation dose
Benefits typically outweigh risks

Question 12

Nuclear Medicine

Answer 12

Molecular tracers tagged with radioactive atoms
Taken up orally or through IV
Wait a bit
Gamma camera captures emission

Question 13

Single Photo Emission Computed Tomography

Answer 13

Single photon travels through body to camera
Good only for function
Need CT for anatomical information

Question 14

Common isotopes for SPECT

Answer 14

Iodine-123 for Thyroid
Indium-111 for Treatment planning
Thallium-201 for Cardiac
Technetium-99m For everything

Question 15

NM benefits and drawbacks

Answer 15

Sensitivity
Functional imaging gives additional info
Limited resolution
Requires CT for anatomy
High patient dose
Complex to quantify

Question 16

PET Scan

Answer 16

Short half life
Internal uptake 
Positron meets electron to form two photons
Photons interact in tissue
PET is quantitative activity/ml

Question 17

FDG

Answer 17

Flourodexoyglucose
Most Common Tracer for PET
Taken up in brain kidney and cancer cells

Question 18

PET Benefits and Drawbacks

Answer 18

Sensitive
Functional
Limited Resolution
Requires CT for anatomy
Higher patient dose
Expensive

Question 19

MRI

Answer 19

High magnetic field
Uses non ionizing radiofrequency
Proton spin aligns with magnetic field and RF pulse shifts spin 90 degrees

Question 20

T1 and T2 Weighted MRI

Answer 20

Longitudinal relaxation (T1)
Transverse relaxation (T2)

Question 21

MRI Drawbacks and Benefits

Answer 21

Good soft tissue
High Res
Different contrast
Non-ionizing radiation
Long scan times
Expensive
Patients may not be eligible
Low sensitivity

Question 22

Ultrasound

Answer 22

Most widely used imaging model

Reflected sound is detected by transducer to indicate depth

Question 23

Applications of Ultrasound

Answer 23

Anesthesiology
Cardiology
Gastroenterology
Neonatology
Obstetrics
Urology
Musculoskeltal
EM

Question 24

Benefits and Drawbacks of Ultrasound

Answer 24

Inexpensive and fast
No radiation dose
Portable
Limited contrast
Difficult to see behind air filled cavities and bone