Final Study Guide Flashcards
Ability dto distinguish two separate objects and visually distinguish them from one another
Resolution
Small Objects = Higher (better resolution)
High Contrast Between (ex: line pariing test)
Sharp Interface (Line to space; step function)
Identify Separation (line pairs)
Defined by line pairs
(Related to occupying space)
Spatial Resolution
Distinguish between Low & High Property of being noticeably different Similar contrast objects Any size and shape Small change in size and density
Contrast
Unwanted, non useful signal
Obscures (hide) the useful signal
Audio- background hiss; difficult to hear words
Visually unclear; difficult to see detail
Noise
Noise can be sperated into (4) components, what are they?
Graininess
Structure Mottle
Quantum Mottle
Scatter Radiation
Not Smooth Grain-like particles "large particles" Noise Depends on distribution and size of image (size and spacing of pixel size) Smaller = less noise
Graininess
smaller pixel size = more detail = less noise
Noise comes in (2) types of Mottle what are they?
Structure & Quantum
Spots/smear- similar to graininess; structure of intensifing screen
Dependent on imaging system
Structure Mottle
Random nature of radiation interaction with detector More quanta (photons) = less Quantum Mottle More data reduces Quantum Mottle
Quantum Mottle
Increasing the number of photons; increases the quality of the picture
Improved with: Detector close to object/ Use of screen grid
Scatter Radiation
Irregularity on an image that is not caused by the proper shadwoing of tissue by the primary x-ray beam
Artifacts (not part of the original object)
Image Receptor Artifacts are problems that include:
Dirt
Scratches
Pixel malfunction
Ghost images
What are solutions of image receptor artifacts?
Clean detectors
Replace the damaged receptors
Window level Window Width Range/scaling Image Compression Make sure enough data is available
Software Artifacts
How many cancer patients will receive radiation therapy during thier illness?
2/3
What is ASTRO responsible for?
Support national medical error reporting system
Improve the integration of equipment used in Rad Onc
Demonstrate respect for protecting the rights of patients and being responsive to patient needs and concerns
How are the most common medical errors caused?
Faulty systems, processes and conditions that lead people to make mistakes or fail to prevent them
What is James Reason model called
Swiss Cheese Model
Point of contact where error is made
Active Error
Sips & Lapses/Mistakes
Failures in design upstream in the process which allow inevitable active errors to cause harm
Latent Error
Failures of planned behavior or lapse in concentration; attentional faliure
Slips
Occur during competing sensory or emotional distractions, fatigue or stress
Slips
Failures of memory; often occur during routine tasks
Lapses
Violation
Work around
Path or least effort or cost
Sabotage
Active Error- Mistakes
Inconrrect choices, lack of experience, insufficient training, negligence
Unintentional
Violations
Intentional
Active Error- Mistakes (knowgelge base errors)
Outside experience or training
No immediate solution- search options
Tendancy to acept first option
Society, culture, regulatory factors Organization/managment Team factors Enviornmental factors Individual factors
Latent errors
Ex: I didnt notice the bolus was not in place
Error classification: Skill based slips and lapses
Ex: I know this patient, I dont need to read the perscription today
Error Classification: Rule based errors
Ex: Increase dose rate to shorten treatment time
Error Classification: Rule based errors
