Clinical Safety Flashcards
Amount of acoustic energy the patient receives
acoustic exposure
as low as reasonably achievable; used to reduce biological effects in humans and the fetus
ALARA principle
effect of ultrasound waves on living organisms, including their composition, function, growth, origin, development and distribution.
biological effect
interaction of the sound wave with microscopic gas bubbles found in tissues
cavitation
studies of various factors determining the frequency and distribution of diseases in the human community
epidemiology
study of human body at work
ergonomic
refers to experimentation done in or on living tissue in an artificial environment outside the organism
ex vivo
refers to the technique of performing a given experiment in a test tube or, generally, in a controlled environment outside a living organism
in vitro
refers to experimentation done in or on the living tissue of a whole, living organism as opposed to a partial or dead one. Animal testing and clinical trials are forms of this research
in vivo
describes the likelihood of cavitation occurring
mechanical index (MI)
an act passed by congress to assure safe and healthful working conditions
Occupational Safety and Health Act (OSHA)
average intensity throughout the pulse duration
pulse average (PA)
force exerted by the sound beam on an absorber or reflector
radiation force
average intensity across the entire sound beam
spatial average (SA)
peak intensity found across the sound beam
spatial peak (SP)
average intensity during the pulse repetition period
temporal average (TA)
greatest intensity during the pulse
temporal peak (TP)
relates to the heating of tissue
thermal index (TI)
relates to heating of bone
thermal index for bone (TIB)
relates to heating of cranium
thermal index for cranium (TIC)
relates to heating of soft tissue
thermal index for soft tissue (TIS)
injuries that are caused or aggravated by workplace activities including injuries of the muscles, tendons and joints
Work-Related Musculoskeletal Disorders (WRMSD)
Act passed by congress in 1970 to assure safe and healthful working conditions
OSHA
WRMSD involve musculoskeletal disorder symptoms that remain for ___ days or more.
7
Greater than 80% of monographers have some form of WRMSD, most common is?
Shoulder pain
What are some causes of WRMSD in sonography?
- static work posture
- awkward scanning posture
- forceful and repetitive movements
- prolonged abduction of upper extremity
- inappropriate monitor height
- incorrect or continual grip of the transducer
Inflammation of a joint bursa, commonly the shoulder
bursitis
Causes of bursitis?
- repetitive motion
- repeated are abduction restricts blood flow to the soft tissues
Entrapment of the median nerve as it runs through the carpal bones of the wrist.
Carpal tunnel syndrome
Causes of carpal tunnel syndrome
- repeated flexion and extension of the wrist
- mechanical pressure against the wrist
Entrapment of the ulnar nerve as it runs throughout the elbow
Cubital tunnel syndrome
Causes of cubital tunnel syndrome
- repeated twisting of the forearm
- mechanical pressure against the elbow as it rests on the exam table
Specific type of tendonitis of the thumb
de Quervain’s disease
Causes of de Quervains disease
repeated gripping of the transducer
Inflammation of the periosteum area of the insertion of the biceps tendon into distal humerus.
Epicondylitis
Causes of Epicondylitis
repeated twisting of the forearm
Fraying or tearing of the rotator cuff of the shoulder
Rotator cuff injury
Causes of rotator cuff injury
- repeated arm abduction
- repetitive motion
Intervertebral disk degeneration
Spinal degeneration
Causes of spinal degeneration
- awkward posture
- static postures
Inflammation of the tendon and sheath around the tendon
tendonitis
causes of tendonitis
- repetitive motion
- repeated arm abduction
Nerve entrapment that can occur at different levels
Thoracic outlet syndrome
Causes of thoracic outlet syndrome
- repetitive motion
- awkward postures
Inflammation and swelling of the tendon sheath in a finger entraps the tendon and restricts the motion of the finger
Trigger finger
causes of trigger finger
repeated gripping of the transducer
causes of trigger finger
repeated gripping of the transducer
Prevention of injury includes:
position table at proper height
eyes even with top of monitor
elbow close to body etc
Who regulates ultrasound instruments according to application, output intensities, and thermal and mechanical indexes?
FDA (food and drug administration)
Who recommends prudent use of ultrasound in the clinical environment by minimizing exposure time and output power?
AIUM (american instate of ultrasound medicine)
With ALARA principle the ____ must outweigh the risks?
benefit
Amount of acoustic energy the patient receives in units of s.
acoustic exposure
power divided by area
units of W/cm^2 or mW/cm^2
intensity
rate at which work is performed
units of mW
Power
Force divided by area
units of Pa, MPa, or mm Hg
Pressure
Spatial Peak (SP)
- greatest intensity across sound beam
- usually located at center of the sound beam
Spatial Average (SA)
- average intensity across entire sound beam
- equal to total power across beam divided by beam area
Temporal Peak (TP)
greatest intensity during pulse
Temporal Average (TA)
- average intensity during transmitting and receiving times (Pulse repetition period)
- equal to the PA intensity X duty factor (DF)
Pulse Average (PA)
- average intensity over entire duration of the pulse
- For continuous wave, the pulse average is = to temporal average
Spatial Average-Temporal Average (SATA)
- averages spatial and temporal intensities of beam
- lowest intensity value given for a sound beam
- intensity measured during both pulse and receiving time
- heat is the most dependent on SATA intensity
Spatial Peak-Temporal Average (SPTA)
- average intensity at center of sound beam
- used to describe pulse ultrasound intensities and determine biological effects
- measured during PRP
- typically higher that SATS values by a factor of 2-3 for unfocused and 5-200 for focused transducers
Spatial Average-Pulse Average (SAPA)
- average intensity within beam throughout the duration of pulse
- measured during pulse duration
Spatial Peak-Pulse Average (SPPA)
- Average intensity that occurs during the pulse
- measured during pulse duration
Spatial Average-Temporal Peak (SATP)
-average intensity within the beam at the highest intensity time
Spatial Peak-Temporal Peak (SPTP)
- peak intensity of sound beam in both space and time
- highest intensity value for a given sound beam
What has lowest output intensity?
imaging instruments
What has highest output intensity?
Pulsed-wave doppler
What has highest output intensity?
Pulsed-wave doppler
No confirmed significant biological effects in mammalian tissue for exposures below _______ with unfocused transducer and _____ with focused transducer.
100mW/cm^2
1 W/cm^2
What can increase the risk of cavitation?
introduction of bubbles into tissues and circulation from contrast agents
Sable Cavitation
- involves micro bubble already present in tissues
- when presure is applied, micro bubbles will expand and collapse
- bubbles can intercept and absorb large amount of acoustic energy
Transient Cavitation
- dependent on pressure of ultrasound pulse
- may occur with short pulses
- bubbles expand and collapse violently
- pulses with peak intensity greater than 3300 W/cm^2 (10 MPa) can induce cavitation in mammals
