Shared Flashcard Set

Details

112
Exam 2
55
Medical
Professional
04/15/2012

Additional Medical Flashcards

 


 

Cards

Term
Piezoelectric Crystals
Definition
Reversible conversion of electrical energy to mechanical deformation
Term
Piezoelectric crystals can be made from:
Definition
Naturally occurring crystals (sugar, quartz)
Man-made crystals (quartz-like substances)
Ceramic-based materials – Most Contemporary Transducers
Polymers {Polyvinylidene fluoride (PVDF)
Term
Scintigraphy:
Definition
A two-dimensional picture of a body radiation source is obtained through the use of radioisotopes.
Term
X-ray:
Definition
Short wavelength electromagnetic radiation of produced when high-speed electrons strike a solid-state target (radiographic film).
Term
Examples of Scintigraphic Techniques
Definition
Thallium treadmill stress test
V/Q scan looking for pulmonary embolus in lungs
PET and CT imaging for tumors or cancer, or PE
Angiogram (or myo-, arterio-, veno-, or lympho-)
Term
PET
Definition
Positron Emission Tomography
Nuclear medical imaging technique
Produces a three-dimensional image of functional processes in the body
Detects radioisotopes, which are introduced into the body on a metabolically active molecule.
Term
CT
Definition
Computer (Aided) Tomography

Uses x-ray technology to create images
Produce multiple images of the body part being examined (from different angles)
Computer joins them together, in cross-sectional views
The images can then be examined on a computer monitor or printed
Term
Transducers
Definition
Change a physical property to electrical energy
Term
Detectors (in general)
Definition
Respond to physical or physiological changes in the body
Term
Three Categories of Signal Conditioners
Definition
Amplifiers :Alter the energy level of the signal
Filters: Alter the frequency content of the signal
Signal Processors: Derive (new) information from the (old) signal
Term
Amplifiers
Definition
Alter the energy level of the signal
Term
Filters
Definition
Alter the frequency content of the signal
Term
Signal Processors
Definition
Derive (new) information from the (old) signal
Term
Amplification ratio?
called?
Definition
output/input
called SENSITIVITY or GAIN
Term
Biological signals are __________ in amplitude
Definition
small, In the microvolt to millivolt range; considered low level signals
Term
Output device signals require __________ amplitudes
Definition
large, In the volts range, 1- 10 volts (or more); considered high level signals
Term
harmonic distortion:
Definition
In the output signal of a device, distortion caused by the presence of frequencies that are not present in the input signal.
Term
total harmonic distortion (THD):
Definition
When an amplifier is driven with a signal, the output of the amplifier is an amplified version of the input signal plus any distortion of the signal created by the amplifier. All signal processors add distortion.
Term
A harmonic multiple:
Definition
a multiple of the fundamental frequency. For example, a harmonic frequency of 300 Hz developed in a 60-Hz system, is the fifth harmonic (300 Hz / 60 Hz = 5).
Term
The maximum input signal level is called:
Definition
the saturation voltage
Term
The maximum output voltage is limited by the __________ __________ __________.
Definition
power supply voltage
Term
Electrical impedance, or simply impedance, describes __________ to sinusoidal alternating (AC) current.
Definition
opposition
Term
Impedance extends the concept of __________ to AC circuits, describing not only the relative amplitude of the voltage and current, but also the relative phases.
Definition
resistance
Term
Noise
Definition
Introduced in the amplification process
Inevitable product of electronic components
Measured in either decibels or peak output voltage produced by the amplifier when no signal is applied
Term
Saturation
Definition
When an amplifier reaches its maximum capacity & cannot amplify any further (or saturation voltage)
The result is a distortion, known as clipping. Only some of the signal is being amplified. Where is the rest of the signal?
Term
__________ filters utilize resistors, capacitors & inductors to operate.
Definition
Analog
Term
filters use computer code to operate.
Definition
Digital
Term
A decibel is a __________ value
Definition
logarithmic
Term
An important reference value is a change of __________ in any signal power, voltage or current.
Definition
3 dB
Term
A decibel (dB) change for: Voltage or Current is calculated as of __________ the ratio. Therefore, a reduction of 3 decibels in voltage or current results in a reduction __________ __________ of the original value
Definition
20 log10; to 70.7%
Term
A decibel (dB) change for: Power is calculated as __________ of the ratio. Therefore, a reduction of 3 decibels in power results in a reduction __________ __________ of the original value
Definition
10 log10; to 50%
Term
Filters content __________ __________ __________ of a signal
Definition
alter the frequency
Term
High Pass Filter
Definition
A filter that passes frequencies above a specified cut-off frequency (fco)
Term
Low Pass Filter
Definition
A filter that passes frequencies below a specified cut-off frequency (fco)
Term
Band Pass Filter
Definition
A filter that passes frequencies between two cut-off frequencies, but removes all other frequencies above & below the cut-off frequencies.
Term
Band Reject, or Notch Filter
Definition
A filter that passes frequencies below a cut-off frequency and above a second cut-off frequency but removes all frequencies in-between.
Term
Pass band
Definition
filter not functional, or active
Term
Transition band
Definition
filter begins to perform function
Term
Stop band
Definition
filter considered operational, or functional
cut-off frequency (fCO)
-3 Db or 50% or 70.7% of
original signal
Term
A filter is said to be “active in the __________ band” because the frequencies in that range do not have enough energy to perform “__________”.
Definition
stop; work
Term
Functional cut-off frequency:
Definition
the point at which the frequency reaches a 3 dB reduction of the original signal amplitude.
Term
A reduction to 70.7% of the signal’s original __________ amplitude.
Definition
current or voltage
Term
A reduction to 50.0% of the signal’s original __________ amplitude.
Definition
power
Term
Roll-off:
Definition
The steepness or slope of signal amplitude reduction
Term
Signal Processors:
Definition
Derive NEW information from the signal
Term
CRT
Definition
Cathode Ray Tube
Term
LCD
Definition
liquid crystal diode
Term
Plasma
Definition
neon & xenon ionized to plasma
Term
Primary Storage
Definition
Access time measured in nanoseconds (10-9)
Temporary RAM (fixed within the circuitry)
This is the CPU or central processing unit
Math, Algebra, and Logical Operators occur here
Solid State components
No moving parts
Nothing to wear out
Enemy is heat generated when processing
Term
Secondary Storage
Definition
Access time measured in milliseconds (10-3)
Hard drive, thumb or flash drive, external drive
Currently, a rotational device with access arm
Head can “crash” into the hard drive, destroying some or all of your data
Requires dust-free environment
Future secondary storage devices moving toward solid state (no moving parts) but currently expensive
Term
Tertiary (when time is not the issue, volume is)
Definition
Extraordinarily massive data storage system
Thousands of CD’s or hard drives
Climate-controlled environment
Extremely slow (10-60 seconds) access time or more
CD or hard drive media storage
Information accessed via robotic arm by electronic request
Term
DICOM
Definition
Digital Imaging and Communications in Medicine

A standard for handling, storing, printing and transmitting information in medical imaging.
Includes a file format definition and a network communications protocol.
DICOM files can be exchanged between two sites capable of receiving image and patient data in DICOM format, similar to internet but “private”.
Devices include scanners, CPU’s, printers, any form of monitor, and storage devices including CD or DVD.
Media can be in optical or solid-state format.
Modem and Internet transmission / reception in
DICOM format are used for longer distance transfers.
Devices are referred to as being “DICOM compatible”.
Term
PACS
Definition
Picture Archiving and Communication Systems
ACS are migrating from radiology reading rooms into cardiology, oncology, operating rooms (OR), emergency rooms (ER), the cath, vascular and echo lab, physicians’ offices and across the healthcare enterprise (for hospital-wide access). DICOM compatible.

3D/4D Advanced Visualization Capability
Richer Image Databases
On-Demand Access to Accurate, Detailed Images and Prior Exam Data
Greater Storage Needs – File Size, Sharing, Distribution
Term
BNC
Definition
Bayonet Neill Concelman connector
Supporting users have an ad free experience!