Exam 2- Ultrasound, Diathermy , Low-Level Laser Therapy

What type of energy does ultrasound use?

Acoustical energy

How can ultrasound be used as a heating modality?

Penetrates skin and subcutaneous fat

Heat muscles, tendons, ligaments, joint capsules etc

Non thermal effects of ultrasound

Mechanical effects

How does ultrasound work?

Electrical current passed through crystal causing it to vibrate

Sound waves generated by vibration of the crystal

Frequency range of ultrasound?

1MHz to 3.3Hz

What duty cycle do you use with ultrasound to do tissue heating?

Continuous

What duty cycle do you use with ultrasound for mechanical/non-thermal effects?

Pulsed

What is the mechanical deformation of a crystal that causes an electrical current to form?

Piezoelectric effect

What is it when alternating current is passed through a crystal?

Reverser Piezoelectric effect (indirect)

Reverse Piezoelectric effect results in?

Very fast contraction and expansion of the crystal

Vibration produces high frequency sound waves

Reverse piezoelectric effect requires a ________ voltage

High voltage

What is the near field of the ultrasound beam?

TREATMENT AREA

-Fresnel zone

What is the far field of the ultrasound beam?

Fraunhofer zone

Where does direct treatment of the ultrasound beam occur?

Near field (fresnel zone)

Where does indirect treatment of ultrasound occur?

Far field (Fraunhofer zone)

What is the peak intensity or maximum intensity of ultrasound?

Spatial Peak Intensity (ISP)

watts per cm squared

What the average intensity of ultrasound?

Spatial average intensity

ISP x duty cycle

What is the area of the sound head that produces sound energy?

Effective radiating area (ERA)

-basically the size of the crystal

The effective radiating area is always _______ Ethan the size of the ultrasound head?

Smaller

-ideally only slightly smaller

What is the ratio between the peak intensity of the ultrasound be a divided by the average intensity of the ultrasound beam?

Beam Nonuniformity Ratio (BNR)

What is the ideal beam nonuniformity ratio (BNR)? What is an acceptable range?

Ideal= 1 (1:1)

Acceptable (2-8)

The ______ the BNR the more uniform the intensity of the sound wave

Lower

A lower BNR does what?

Eliminates hot spots

Allows higher dosage without discomfort

Greatest comfort and safety

Air is a ______ conductor of ultrasound

Poor

Use a ________ to prevent reflection of sound waves by air

Give examples

Coupling medium

Ultrasound gel and gel pads

What is indirect ultrasound?

Underwater ultrasound

-plastic basin or bucket filled with water

More watts with ultrasound means?

More HEALING

NOT greater penetration

What is the amount of sound energy being emitted form the sound head?

Amplitude of sound waves

What dictates the depth of healing for ultrasound?

Frequency

Duty cycle of ultrasound can be?

Pulsed (interrupted) or continuous

Frequency has what 2 affects on ultrasound?

Depth at which greatest amount of energy is absorbed

Time required to cause an increase in tissue temp

What frequency is good for superficial parts?

3.3 MHz

What frequency is good for penetration?

1 MHz

A higher protein concentration means _______ absorption

Higher

A higher density in tissue means ______ absorption rate

Higher

What type of tissue absorb the most ultrasound?

Bone

Tendon

Cartilage

Ligaments

Joint capsules

What type of tissue absorb the least ultrasound?

Skin

Fat

What happens when US waves encounter a boundary between tissues

Scattering

What type of scattering is the reversal of the direction of propagation of the ultrasound wave?

Reflection

(Bounces back)

What type of scattering is the change of ultrasound wave form a straight path when passing obliquely from one medium to another?

Refraction

(Bends the ray)

The acoustic impedance of muscle, fat and water is?

Low

Ultrasound energy is reflected at _________ interface, leading to?

Soft tissue-bone

Increased healing (so keep applicator moving)

The refraction of the ultrasound energy within the tissue can lead to concentrations of ultrasound at?

The point of refraction

(Ex: tendon joins bone)

1 degree increase in temp is associated with?

Increase in metabolic activity

2-3 degree increase in temp is associated with?

Reduction is muscle spasm

Increases blood flow and reduction of chronic inflammation

4 degree increase in temp is associated with?

Alter visoelectric properties of collagen

(Makes collagen more stretchy, helps scar tissue)

What increase in temp is good for the repair phase of healing and NOT acute phase?

1 degree increase

_________ times are needed when lower intensities are used?

Longer times

Therapeutic effects of ultrasound that increase things

Increased extensibility of collagen fibers and joint capsules

Increase blood flow

Increase cell metabolism

Increased collagen synthesis

Enhance tendon, ligament and muscle healing

Therapeutic effects of ultrasound that decrease things

Decreased joint stiffness

Decreased muscle spasm

The thermal effect of ultrasound is?

Only temporary

Superficial layers of cool ______ than deeper tissues

Faster

What should be performed after ultrasound

Tissue manipulation or stretching

Pulsed ultrasound, non thermal effects has been shown to effect tissue healing and alter cellular activity how?

Stimulation of fibroblast activity

Increased blood flow

Increased proteins associated with injury repair

Through what does pulsed ultrasound affect tissue healing and alter cellular active?

Acoustical streaming

Stable cavitation

What is the movement of fluids along cell membranes due to mechanical pressure exerted by the sound waves?

Acoustical streaming

Movement during acoustical streaming occurs in what direction?

Direction of the sound waves

Acoustical streaming facilitates and increases what?

Facilitates fluid movement

Increases cell membrane permeability

What is the formation for gas filled bubbles from pressure recharges in tissue fluids? These bubbles expand and contract with ultrasound waves

Cavitation

What is a rhythmic expansion and contraction of bubbles during repeated pressure changes over many acoustic cycles?

Stable cavitation

Stable cavitation facilitates what?

Fluid movement and membrane transport

What is the collapse of gas bubbles which may cause tissue damage?

Unstable cavitation

Unstable cavitation is associated with?

Low frequency high intensity ultrasound (not therapeutic)

Contraindications for ultrasound

Malignancy

Hemorrhage

Ischemia

Thrombus

Infection

Gonads

Eye

Pelvic, abdominal and lumbar ares of pregnant women

Spinal cord after laminectomy

Plastic or cemented implants (metal is OK)

Near or over electronic implants

Unknown etiology

Risks of ultraound

Bony prominences (use indirect technique and smaller sound head to treat these)

Epiphyseal plate (may alter bone growth)

Do not exceed a peak intensity of?

8.0 W/cm2

In lab what intensity do we use?

1.2 W/cm2

Treatment area of ultrasound should be?

2-3 times the size of ERA

-larger areas: healing wont be achieved

Treatment time of ultrasound

Typically 5-8 minutes

Little as 1 or 2 minutes

Never treat for more than a total of?

15 minutes

How to do a large treatment area?

Break it into 2 or 3 smaller areas and treat for 5 minutes per region

What uses sound energy to drive medication into the tissue?

Phonophoresis (sonophoresis)

TRUE or FALSE

The medication does not need to have a charge to be used in Phonophoresis

TRUE

Ultrasound head becomes the ____________ when used with a dispersal pad in Ultrasound and Electrical Simulation (combo)

Treating electrode

Combo therapy is used for?

Trigger points

Epicondylitits

Superficial pain areas

Decrease adhesions

What is good for the stimulation of fracture healing?

Low intensity pulsed ultrasound

What is a high frequency electromagnetic energy that generates heat in the body tissues?

Diathermy

What generators are used for diathermy?

Shortwave and microwave

What is the most common type of diathermy unit?

Shortwave

Microwave diathermy is how many MHz?

2450 MHz

-FCC regulated

Thermal effect where dipolar molecules (water) rotate?

Dipole rotation

-molecules with a positive and negative side

What thermal effect is it with ions are in the solution and oscillate back and forth?

Ionic oscillation

-sodium, potassium, Charlie's

What type of energy rotation produces thermal energy?

Kinetic energy

What type of electrode produce electrical fields?

Capacitor electrodes

What type of electrode produce a magnetic field?

Induction electrodes

What type of technique is with capacitor electrodes?

Capacitive technique

What type of technique is with inductive technique?

Inductive technique

With a capacitive technique the tissues a re placed in an ________ field

Electric field

With capacitive technique there is the greatest absorption in tissues with?

Low electrolyte and water content

-adipose

-subcutaneous fat heated more than muscle

What type of technique should you use for patients or areas with low sub cutaneous fat?

Knee foot hand shoulder

Thin patients

With an inductive technique tissues are placed in a __________ field

Oscillating magnetic field

Inductive technique has the greatest absorption in what type of tissue?

High electrolytes, high dipole tissue

-deeper

-muscle, muscle, joint

What type of technique should you use for patients with more sub cutaneous fat and obese patients?

Inductive technique

What are the 4 laws with diathermy?

Arndt-Schultz Law

Grotthuss-Draper Law

Inverse Square Law

Cosine Law

What law is the dose vs response law?

Arndt-Schultz's law

With a small dose it _______ tissues

Stimulates

With a large does it______ tissues

Inhibit

What law says absorption vs therapeutic effect? It has to be absorbed by tissues to have a therapeutic effect?

Grotthuss-Draper Law

What law says the further the distance the lower the dose?

Inverse Square Law

-1/4 the heat with 2x the distance

What law explains the angle of application and reduced energy if angle is increased?

Cosine Law

-perpendicular angle means the most amount of absorbed