SATA

Space-Averaged Time-Averaged

Frequency

1Mhz=1000,000 vibration per second

W/cm2

Ultrasound intensity unit, watts per cm2

ERA

Area of the sound head that produces mechanical
waves

BNR

Convergence Pulsed shockwave - Optimised biological effect
of repeatitative pulse rate 100Hz and width 2.5ms

Beam uniformity Ratio (BNR)

Ratio of 4:1 is good. It is the ration between spatial
peak intensity to the average intensity

About ultrasound physics

Cavitation

The formation of tiny gas bubbles as a result of
ultrasound vibration

Cavitation caused

Micro streaming and Bulk streaming, where Micro
streaming is more mechanically power ful than bulk steaming

Micro-streaming

Can only alter cell membrane permeability and
stimulate the cell activity

Bulk streaming

A movement of the fluid in a single direction in the
ultrasound field in a liquid

Types of cartilage

Articular cartilage, Fibro-cartilage and Elastic cartilage

Articular cartilage

Covers gliding surfaces of joint, is a complex living soft
tissue that lines the bony surface of joints and provides
a low friction surface that enables the joint to withstand
weight bearing needed to perform daily activities, such
as walking

Fibro-cartilage

Spongy-like structure found in knee meniscus and
intervertebral discs consisting of fine collagen fibers,
type I collagen and type II collagen

Elastic cartilage

Found in the outer ear and epiglottis which contains
elastic fiber networks and collagen fibers, able to
withstand repeated bending

PGs

Glycosaminoglycan which are disaccharide molecules,
chondroitin and keratin sulfate, connected to the core
protein. Glycosaminoglycans are highly polar and attract
water. They are therefore useful to the body as a
lubricant or as a shock absorber.

Osteoarthritis
(OA)

Articular cartilage injuries can occur by a variety of
causes, such as traumatic accidents, previous knee
injuries, immobilization for long periods or wear and
tear over time. Articular cartilage cells, chondrocytes,
have ability to repair the injured cartilage depend
on the extent of the damage and the location,
however, it is generally very hard to be repaired due
to no direct blood supply in the articular cartilage.

Therapeutic ultrasound
penetration

1Mhz; 5cm deep
3Mhz; 1-2cm deep

Intensity Chart for Tendons

Frequency (1MHz)
Acute 0. 2 -0.4 w/cm2
Subacute 0.6 - 1 w/cm2
Chronic 1.2 - 1.5 w/cm2

Intensity Chart for Muscles

Frequency (1MHz)
Acute 0.5 w/cm2
Subacute 1 w/cm2
Chronic 1.5 - 1.8 w/cm2

Rationale for Ultrasound

*Acute phase
-Stimulates growth factors
-Angiogenesis 血管生成
-Reduce inflammation by drug transfer
**Sub-acute phase
--Angiogenesis
--Fibroplasia 纖維組織增生
***Chronic
---Remodeling
---Elevate tissue temperature
---Effects on scar tissue

What is Phonophoresis?

Using ultrasound energy to push medication
through the skin to penetrate deeper

How fast should you move the horn on the patient?

3cm/sec

Ultrasound attenuation衰減 coefficient

Blood 0.2
Bone, (cortical外皮的) 6.9
Bone, (trabecular 小梁) 9.94
Dentin 80
Fat 0.48
Muscle 1.09
Tendon 4.7
Soft tissue 0.54

Tendons

Connect muscle to bones, glide in lubricated sheaths are are totally inelastic. Function is primarily movement

Ligaments

Connect bones to bone and generally are more elastic then tendons the function is mainly support of the body

Ankle Sprain

An injury that causes a stretch or tear of one or more ligaments in the ankle joint

Grade I Sprain

Pain with minimal damage to the ligaments

Grade II Sprain

More ligament damage and mild looseness of the joint

Grade III Sprain

Complete tearing of the ligament and joint is very loose or unstable

Ultrasound effects

Ultrasound non thermal effect 1

Synthesis of protein
Synthesis of collagen
Reduction of edema
Diffusion of ions
Reduction of edema
Tissue regeneration
Formation of stronger connective tissue

Ultrasound non thermal effect 2

Increased cellular permeability
Increased vascular permeability
Increased blood flow
Stimulation of phagocytosis

Ultrasound thermal effect

Increased sensory/motor nerve conduction velocity
Increased collagen deposition
Increased blood flow
Reduction of muscle spasm
Increased macrophage activity