Ultra Sound

Question 1

What is an ultrasound

Answer 1

Ultrasound is a form of mechanical energy which causes vibration of molecules to produce sound

Ultrasound Frequencies beyond 20000Hz exceed human hearing

Question 2

What are sound waves

Answer 2

Longitudinal waves of compression and refraction which causes tissue cells to vibrate

Question 3

Properties of ultrasound waves

Answer 3

1. Frequency
2. Wavelength
3. Velocity

Question 4

1. Frequency

Answer 4

Number of times the cells vibrate in a complete cycle 1second measured in MHz

frequencies will vary depending on depth of tissue and penetration required

1MHz = 1 mill cps - Penetrate deeper tissues more effectively

3MHz= 3 mill cps- penetrate superficial tissues more effectively

Question 5

2. Wavelength

Answer 5

Distance between two equivalent points on the wave form

Question 6

Velocity

Answer 6

Speed of the wave travels through the medium

Question 7

What is the beam emitted through

Answer 7

Omitted from Crystal which is situated on the head of the transducer

The transducer is held by the physiotherapist and applied to patients skin

Question 8

Transmission of ultrasound

What is the most effective way to use the transducer

Answer 8

All tissues of the natural impedance to transmission of ultrasound waves

Transducer head should be placed at 90° parallel to skin surface to ensure most effective transmission of ultrasound tissue

Question 9

Transmission of ultrasound

Happens if you hold the transducer wrong

Answer 9

The ultrasound waves cannot travel through the air and will be reflected back to the transducer damage in the crystal this means that the ultrasound waves will not be generated and the subsequent patient treatment will be ineffective

Question 10

Transmission of ultrasound

The use of a medium

Answer 10

The use of a medium is required to bridge the gap between the transducer and the contours of the body

Question 11

Transmission of ultrasound

What is a suitable medium

Answer 11

Oils

Aqueous gels

Water

Creams- Anti-inflammatory

Question 12

Transmission of ultrasound

Why should you clean transducer head

Answer 12

Reduce risk of infection clean with alcohol based wipe pre-and post treatment

Question 13

Absorption and Attenuation of ultrasound in the tissue

Tissues with higher water content and low protein

Answer 13

Absorb the least ultrasound which reduces the potential therapeutic effect

Question 14

Absorption and Attenuation of ultrasound in the tissue

Tissues with low water content and high protein

Answer 14

Tendons and ligaments

Absorb more ultrasound which increases therapeutic effect

Question 15

Absorption and Attenuation of ultrasound in the tissue

Superficial and deep tissue

Answer 15

More ultrasound is delivered to superficial tissues and deep tissues

1MHz =1/2 depth of penetration at 4 cm below the skin

3MHz= 1/2 that the penetration at 2 cm below the skin

Question 16

Therapeutic effects of ultrasound

Answer 16

Helps to give the best possible conditions for healing tissue

Delivered using either a pulsed or continuous mode- depending on desired therapeutic effect

Question 17

What do pulse mode and continuous mode give you

Answer 17

1. Pulse mode= Non thermal effect (acute)

2. Continuous mode= Thermal effect (chronic)

Question 18

Pulse mode= Non thermal effect

Answer 18

Stimulate cavitation and acoustic streaming In tissues and body fluids = excites the tissue cells

Cavitation = formation of gas bubbles in tissues and body fluids

Acoustic = eddying of fluids around a vibrating structure – increases the permeability of the cell membrane and increases cell metabolism – most effective mode of treating acute and subacute conditions

Question 19

what is the normal pulse frequency delivered by ultrasound machines

Answer 19

2 milliseconds

Question 20

Continuous mode= Thermal effect

Answer 20

Stimulates beneficial healing of dense collagen and tissues and can also use hyperaemia

The most effective for tearing chronic conditions

Question 21

Ultrasound and Tissue Repair

How does ultra sound affect tissue repair

Answer 21

Increases efficiency of repair process

Question 22

What does ultra sound stimulate the production off in tissue repair and what happens

Answer 22

During inflammation phase of tissue repair or ultrasound stimulates mast cells platelets white blood cells and macrophages

This encourages cells to progress to proliferation phase

Question 23

What does ultrasound to encourage in the proliferation phase

Answer 23

Stimulates fibroblasts endothelial cells in my fibroblasts to encourage scar tissue formation

Question 24

What does ultrasound to encourage in the remodelling phase

Answer 24

Collagen fivers change from immature type three temperature of type one to increase the tensile strength and ability of the tissue

Ultrasound influences collagen fibre type and orientation

Question 25

Other uses ultrasound

Answer 25

Low intensity pulsed ultrasound (LIPUS) is thought to stimulate fracture healing. Dtimulate the healing of chronic wounds E.g venous ulcers and pressure sores.

Question 26

Contradictions of ultrasound

Answer 26

Contraindications Do not treat over the pregnant uterus Malignancy Acute Bleeding Tissues (within 4-6 hours of injury) Vascular Problems Eg. Emboli, DVT, Atherosclerosis, haemophilia (if not covered with factor replacement) Do not treat over the eye, stellate ganglion, Heart disease, pacemaker, gonads, active epiphyses in growing children

Question 27

Precautions of ultrasound

Answer 27

Always use lowest intensity which produces a therapeutic response Move the transducer slowly throughout treatment to prevent the risk of burns Informed consent must be obtained from the patient prior to commencing the treatment If using a thermal dose – consider all the usual contraindications to the application of heat Be cautious when close to cardiac pacemakers or other implanted electronic devices Do not use Continuous mode U/S over metal implants

Question 28

Calculating the Ultrasound Dosage Machine frequency: depth of lesion

Answer 28

In order to accurately calculate the following issues need to be considered; Machine Frequency: Depth of Lesion - Deep (more than 2cm depth = 1MHz) Superficial (Less than 2cm depth = 3MHz)

Question 29

Calculating the Ultrasound Dosage pulse ratio

Answer 29

Pulse Ratio – Pulsed either – acute (0-2 weeks post-injury) = 1:4 (20% Duty Cycle) or 1:3 (25%) sub-acute (2-6 weeks post injury) = 1:2 (33%) or 1:1 (50%) Continuous- chronic (> 6 weeks post injury) = 1:1 (50%) or CONT (90% - 100%)

Question 30

Calculating the Ultrasound Dosage Intensity

Answer 30

measured in Watts per cubic centimetre) Tissue State: Intensity: Acute - 0.1-0.3 Subacute -0.2-0.5 Chronic -0.5-0.1

Question 31

Calculating the Ultrasound Dosage The area of tissue to be treated relative to the size of the transducer (measured in number of treatment heads).

Answer 31

Example: to treat an acute lateral ligament sprain of the ankle joint Depth of Lesion = Superficial = 3MHz Pulse Ratio = Acute = Pulsed 1:4 Intensity Required = Acute = 0.1 Wcm3 Treatment Area Relative to Transducer Size (1 minute of U/S per treatment area) = 2 heads Dosage Calculation = 1 minute of U/S X Pulse Factor X Number Treatment Heads = 1 X 5 (1:4) X 2 = 10 minutes

Question 32

Recording Ultrasound Treatment

Answer 32

Document the following information in the patient’s treatment record; Position of Patient Area treated (size and location) Machine used Settings/Intensity/Time/Pulse Parameters Any immediate or untoward effects

Question 33

what is ultrasound used for

Answer 33

influence soft tissue repair

Question 34

non thermal effect

Answer 34

Early repair best for inflammation/proliferation stage fibroblasts laying down collagen angenisis and macrophages best for acute and sub acute conditions

Question 35

thermal

Answer 35

heat up collagen fibres

Question 36

how is the doseage of ultra sound calculated

Answer 36

its calculated depending on the stage of tissue healing and the effects wanted

Question 37

what do sound waves cause

Answer 37

>The vibrating cells can either generate heat = thermal affect >Or the generated energy can be absorbed by tissues = non thermal affect