Week 7 Flashcards
Name 4 EPAs
Thermal
Non-thermal
Electrical stimulation
Othes
Thermal EPAs (7)
Hydrocollator (Hot) packs Cryotherapy (Ice/cold/immersion) Continuous Therapeutic Ultrasound Shortwave Diathermy Microwave Diathermy Infrared Wax Bath
Non thermal EPAs (8)
Pulsed ultrasound Low intensity pulsed ultrasound (LIPUS)) Pulsed laser therapy Pulsed shortwave therapy Pulsed electromagnetic fields Magnetic therapies Mircrocurrent therapies shock wave therapy
Electrical Stimulation EPAs (6)
Interferential therapy (IFT)
Transcutaneous Electrical Nerve stimulation (NMES)
Functional Electrical Stimulation (FES)
Microcurrent Therapy (MCT)
Transcranial Direct-Current Stimulation (tDCS)
Other EPAs (4)
Biofeedback (no stimulation)
Electromyograph - Biofeedback
Ultrasound Imaging
Ultraviolet light
pages to review
10,11.12, 25,26,33
Generation of US
An ultrasound wave is generated when an electric field is applied to an array of piezoelectric crystals located on the transducer surface. Electrical stimulation causes mechanical distortion of the crystals resulting in vibration and production of sound waves (i.e. mechanical energy)
Generation of US Part 2
The conversion of electrical to mechanical (sound) energy is called converse piezoelectric effect (Gabriel Lippman 1881)
Frequency dependant on crystalline disc and current applied
Characteristics of Traditional US (3)
High frequency modality (1- 3MHz)
Thermal and non thermal effects
European, Antipodean North American approaches
Characteristics of Long Wave US (4)
Newer modality
45 kHz
Longer wavelength - penetrates more deeply (several metres)
promoted for same uses as traditional high frequency US
What is a transducer
A device that produces sound waves that bounce off body tissues and make echoes. The transducer also receives the echoes and sends them to a computer that uses them to create a picture called a sonogram
What is ERA
Effective radiating arm
What is the power of US measured in
Watts
What is the intensity of US measured in
Wcm^-2
p20
What is the Beam Non-uniformity Ratio (BNR)
Describes the consistency (or uniformity) of the US output ratio
What does the BNR range from
10:1-2:1
Lower = better
What is the Duty Cycle (Pulsed Ratio)
describes the proportion of time the current is actually flowing
e.g. 5s on 10s off - duty cycle is 33% (1:2)
typically 1;1 or 1;4
each pulse lasts about 2ms
What does frequency refer to
number of waves per second
What is frequency measured in
Hertz (Hz)
Do lower or higher frequencies penetrate further into the tissue?
Lower
What are higher frequencies used for
Superficial tissue (3MHz)
What are lower frequencies used for
Deeper tissue (1MHz)
What is Attenuation
Reduction in energy as the ultrasonic wave passes through a medium
includes absorption, reflection, refraction and scattering
Transducer/air percent reflection
99.9
Soft tissue/air percent reflection
99.9
Water / soft tissue percent reflection
0.2
Soft tissue /fat percent reflection
1.0
Soft tissue/bone percent reflection
15-40
What is half depth
The depth in the tissues at which half the surface energy is available
Half - value depth of penetration for muscle fat and tendon (1 and 3 MHz)
Muscle 1(9.0mm) 3(3.0 Fat 1(50mm) 3(16.5mm) Tendon 1(6.2) 3(2.0)
3MHz = 2.0cm 1MHz = 4.0cm
Therapeutic effects of thermal US
Increasing temperature (40-45 degrees )
hyperaemia, resolution of chronic
inflammatory states
The effects of thermal US are dependant on what (4)
MODE of US continuous or pulsed
The vascularity of the tissue
Protein : fat content o the tissue (protein absorbs more than fat)
Frequency /intensity applied
Tissues preferentially heated (7)
Periosteum Superficial cortical bone Joint menisci fibrotic muscle Tendon sheath Major nerve roots intermuscular interfaces
Affects of therapeutic US on the inflammatory stage
Affects membrane potential
stimulates mast cells, platelets, white cells with phagocytic roles and the macrophages
Mast cell degranulation
Pro inflammatory not anti inflammatory
Therapeutic US proliferative
Stimulation of fibroblasts, endothelial cells and myofibroblasts
Increased rate of angiogenesis
Increased protein and collagen synthesis
Proliferative - enhancing and maximising efficiency
Therapeutic US during the Remodelling stage (3)
Enhancing normal deposition & organisation of collagen fibres
Enhancing tensile strength and scar tissue mobility
Effects are dependant on time of initial treatment
Machine settings for US dose calculation
Machine frequency
Pulse ratio
intensity
time
Other factors for US dose calculations
size of lesion
tissue state (stage of healing)
depth of lesion
half depth values
US dose pages
38-40
Contraindications of all EPAs (5)
Those who are unable to comprehend instructions, or who are unable to co-operate.
The application of EPAs over the abdomen, lower back or pelvis is normally contraindicated during the first 35-weeks of pregnancy.
In the area of a tumour where there is active or suspected malignancy, except for palliative care
Areas of recent bleeding tissue or haemorrhage
Active tuberculosis in treatment area
Precautions for all EPAs (4)
Treatment should not normally be carried out:
Over the anterior aspect of the neck
When there is significant impairment in the circulation/sensory loss of the area to be treated
Where there is devitalised tissue e.g. recent radiotherapy
Where there is local acute skin conditions e.g eczema, dermatitis
Contraindications for US
Avoid exposure to the developing foetus (i.e. do not treat over uterus during pregnancy)
Malignancies and precancerous lesions
Vascular abnormalities including DVT, severe arterio/atherosclerosis, emboli
Acute infections
Haemophiliacs not covered by factor replacement
Application over:
Eye • Testes • Stellate ganglion • Cardiac area in advanced heart disease/pacemakers • Spinal cord after laminectomy • Cranium • Active epiphyseal regions in children • Tissues previously treated by deep X-ray or other radiation
Precautions for US (6)
- Anaesthetic areas should be treated with caution if a thermal dose is being applied
- Subcutaneous major nerves and bony prominences
- Always use the lowest intensity which produces a therapeutic response
- Ensure the applicator is moved throughout treatment
- Ensure the patient is aware of the nature of the treatment and the expected effects
- If pain, discomfort or unexpected sensations are experienced by the patient, the treatment intensity should be reduced. If the symptoms persist, the treatment should be terminated.
