19. Stimulus threshold curve, rheobase, chronaxy. High frequency heat therapy, galvanotherapy, iontophoresis.

Question 1

The role of galvanic treatment

Answer 1

• Exploits the analgensic
• Metabolism intensifying effect of direct current

Question 2

What is iontophoresis?

Answer 2

• A charged substance used for medication (e.g, analgesic) is placed on an electrode of the same polarity
• When the current is switched on, the medication can be propelled rapidly through the dermis

(ontophoresis is a treatment for hyperhidrosis — or excessive sweating. It involves sending a gentle electrical current through water to shut down your sweat glands temporarily. I)

Question 3

What is stimulus threshold curve?

Answer 3

A curve in which threshold amplitudes are plotted against the pulse duration

Question 4

What is rheobase (r)?

Answer 4

A minimal electric current which is needed for muscle contraction

Question 5

What is chronaxie (C)?

Answer 5

By doubling the rheobase as amplitude (a = 2r) and for a duration long enough for muscle contraction

→ pulse duration at this time is called chronaxie

Question 6

Are electric stimuli used in stimulus therapy higher than rheobase?

Answer 6

YES

Question 7

The role of electric stimuli

Answer 7

They are used to generate muscle contraction

Question 8

What does this curve demonstrate?

Answer 8

• The response curves to square pulses

→ The rise of voltage is instantaneous

• In case of triangle pulse (exponential pulse)

→ The voltage-rise is more prolonged and its duration is dependent on pulse time

Question 9

If the pulse duration is long enough, how can cell act against the stimulation?

Answer 9

If the pulse duration is long enough, the cell is capable of accommodation

→ ion currents are trigged which act against the stimulation

Question 10

Characteristics of pulse that can trigger muscle contraction

Answer 10

Only pulses that have amplitude larger than the square pulses of the same duration

Question 11

The role of high frequency therapy

Answer 11

• For the treatment of inner organ inflammation
• As an analgesic
• Hyperthermic treatment of tumor

Question 12

Consequences of using high frequency electric pulses?

Answer 12

Using high frequency electric pulses

→ raises the stimulus threshold precipitously

→ trigger heating (have no effect on the medium)

Question 13

Which frequency is used in high frequency heat therapy?

Answer 13

Frequencies over 100 kHz

Question 14

Frequencies over 100 kHz are used in high frequency heat therapy

→ How to produce such high frequency sinusoidal oscillations?

Answer 14

By using a sinus-oscillator

Question 15

High frequency therapy

How is energy produced?

Answer 15

• By using inductive coupling → introducing another LC circuit (coupling circuit, patient circuit) → its inductor is also placed in magnetic field of the inductor of the original oscillating circuit
• The transmission is optimal when the Eigen frequency of 2 LC circuits is the same (there is resonance between them)

→ electrical energy delivered into the tissues during high frequency heat therapy, transforms into heat in the tissue → increasing tissue metabolism

Question 16

Give 3 therapies of high frequency heat therapy

Answer 16

Short wave, decimeter wave, and microwave therapy

Question 17

What are the 2 treatments of shortwave therapy?

Answer 17

1. Capacitor field method
2. Coil-field method

Question 18

Describe capacitor field method

Answer 18

• The treated body part is placed between 2 plates of the treating capacitor

→ An alternating electric field is generated between the 2 capacitor plates

→ Since a half period lasts for a very short time, the charges in the body cannot move significantly

→ In the next half period, the field vector turns, and the charges move in the opposite direction

→ The charges “oscillated” this way impact their kinetic energy onto the molecules → heat is generated

Question 19

Describe coil-field method

Answer 19

The treated body parts enters into the magnetic filed of a treatment inductor coil

→ The inductor induces eddy currents

→ heats muscle tissue

Question 20

coil-field method

Structure of patient circuit applied in coiled field treatment

Answer 20

• An oscillating circuit composed of an inductor coupling coil and a treating capacitor

→ This circuit is used with a patient circuit tuning capacitor

→ patient circuit tuning capacitor is connected parallel with the treatment capacitor

→ tuning the resonance frequency of the patient circuit to the frequency of the oscillator

→ This is when the highest heating effect occurs

Question 21

Describe penetration depth of radiation when using shortwave therapy?

Answer 21

• The penetration depth of radiation in tissue decreases as the frequency increases → the deepest penetration is achieved with short wave therapy

Question 22

Describe penetration depth of radiation when using decimeter and microwave treatment

Answer 22

decimeter and microwave treatments penetrate t a significantly lesser depth into the organism

Question 23

How do decimeter and microwave treatments work?

Answer 23

• Using a special radiating head composed of an antenna and a focusing reflector
  
  • Focusing reflector enables a more intensive heating of smaller areas

Question 24

The relationship between penetration depth of radiation and water content of tissues

Answer 24

The penetration depth of radiation is highly dependent on water content of tissues

→ In the case of less hydrated tissues, the penetration depth at all frequencies is one order higher than in the case of more hydrate tissue

Question 25

Describe hyperthermic treatment of tumors

Answer 25

In the course of treatment, the temperature of tumor is raised up → results in cell destruction

Question 26

Application of microwave treatment

Answer 26

* Used for the widening of narrowed coronary arteries