Lesson 2 (MIDTERM) Flashcards
(42 cards)
Enumerate 3 ways in estimation of patient dose
- Entrance Skin Dose (ESE)
- Mean Marrow Dose (MMD)
- Genetically Significant Dose (GSD)
X-ray exposure to the skin
Most often is referred to as the _____
ESE; Patient dose
Average gonadal dose given to members of the population who are of childbearing age
GSD
GSD. Annual dose
100 mrad/yr (in US)
ESE. expressed in
mR
It is used widely
ESE
ESE. Rationale
o Easy to measure
o Reasonably accurate estimates can be made
MMD Estimated from _____
ESE
MMD. ____ of active bone marrow
50%
Overutilization must be controlled
Emergency Room CT
Average radiation dose to the entire active bone marrow
MMD
It should not include x-ray examination for _____ patient, especially fluoroscopic examination
Periodic Health Examination
asymptomatic
Repeat examination. repeat rate busy hospital
should not exceed 5%
three methods of estimation in ESD
- Use of TLD
- Use of nomogram
- Know the output intensity for at least one operating condition
ESD. Fluoroscopy
difficult to estimate
Routine examination should not be performed when there is no precise medical indication
Unnecessary Examination
_____ examinations should not be performed for routine hospital admission when _____ of disease is found
Hospital Admission
Chest x-ray
no clinical indication
_____ & _____ x-ray examination are not justified
Preemployment Physical
Chest & lower back
Repeat examination. repeat rate all examination
10%
Repeat examination. Highest Repeat Rate Examination:
lumbar, thoracic & abdomen
This should not be done
Whole-Body Multislice Spiral CT Screening
Higher kVp: _____ mAs
Results.
Radiographic technique
Reduces
o Reduced patient dose
o Too low contrast
Enumerate responsible for repeats
- Poor radiographic technique
- Primary
- Too light or too dark
- Motion
- Improper collimation
- Dirty screens
- Improperly loaded cassettes
- Light leaks
- Chemical fog
- Artifacts
- Wrong projection
- Improper patient preparation
- Grid errors
- Multiple exposure
Repeat examination. enumerate caused
- Radiologic technologist error (Most common)
- Equipment malfunction
