Diathermy

Question 1

what is electromagnetic radiation

Answer 1

radiation composed of (you’ll never guess it) electric and magnetic fields that vary over time and are oriented perpendicular to one another

Question 2

what are the physical agents that use electromagnetic radiation (EMR)

Answer 2

infrared light
ultraviolet lights
cold laser
diathermy

Question 3

explain wavelength and tissue penetration

Answer 3

longer waves = deeper penetration

Question 4

how are frequency and wavelength related

Answer 4

inversely

greater frequency = shorter wavelengths

Question 5

wavelength definition

Answer 5

length of wave from peak to peak

Question 6

inverse square law

Answer 6

intensity at the target is equal to the inverse of the distance from the source

ie = longer distance means less energy delivered

Question 7

cosine law

Answer 7

angle of incidence of the beam with the tissue

• perpendicular = most energy delivered, less if not

Question 8

what is the effect of EMR mostly determined by

Answer 8

frequency and wavelength

Question 9

arnold schultz law

Answer 9

a minimal amount of stimulus is needed to initiate biological processes

as the stimulus grows, there will be a point in which it no longer is beneficial and will become detrimental

Question 10

physiological effects of EMR

Answer 10

thermal/nonthermal mechanisms

Question 11

thermal effects are seen via EMR on superficial / deep tissue by which modalities

Answer 11

superficial tissue = Infrared radiation

deep tissue = continuous shortwave and microwave diathermy

Question 12

non thermal effects of EMR are seen in superficial/deep tissue via which modalities

Answer 12

superficial = UV radiation

deeper = pulsed shortwave diathermy

Question 13

explain dipole rotation

Answer 13

ions with a positive and negative charge will spin when placed between positive and negatively charged plates
–> will cause for more energy to be produced

– ionic will only go from positive to negative and vice versa

Question 14

physiological thermal effects of diathermy

Answer 14

vasodilation

increased:
nerve conduction velocity
pain tolerance
tissue extensibility
metabolic activity

decreased:
muscle spindle activity
muscle spasms
muscle strenght

Question 15

nonthermal effects of diathermy

Answer 15

alter membrane permeability/function

attraction of fibroblasts, macrophages, lymphocytes, collagen
–> promote healing process

repolarization of damaged cells

Question 16

how does diathermy work

Answer 16

waves of radiofrequent radiation absorbed by the body are converted to heat

Question 17

shortwave diathermy specifics

Answer 17

27 MHz (3-200m wavelength)

continuously or pulsed

Question 18

microwave diathermy specifics

Answer 18

2450 MHz (1mm to 1 m wavelength)

Question 19

continuous short wave diathermy effects

Answer 19

thermal effect
≥ 80-120 Watts

Question 20

pulsed shortwave diathermy effects

Answer 20

vasodilation (≥ 38 Watts)

Question 21

pulsed shortwave diathermy for vasodilation in relation to

pulse duration
frequency
peak pulse power

Answer 21

duration = 0.25 ms
frequency = 250 pps
power = 750 watts

Question 22

pulse period related to pulsed shortwave diathermy

Answer 22

4 miliseconds

Question 23

what are the two main subtypes of shortwave diathermy

Answer 23

capacitive
inductive (via magnetic)

Question 24

what are the types of capacitive shortwave diathermy treatments

Answer 24

series - contraplanar
parallel - coplanar

Question 25

formula for heat

Answer 25

(I²) x Resistance x Time

Question 26

what type of resistors are in series for capacitive diathermy

Answer 26

contraplanar

Question 27

what type of resistors are in parallel for capacitive diathermy

Answer 27

co-planar

Question 28

in a series circuit, how is total resistance calculated

Answer 28

resistance of current flow is equal to the added total of all components together

Question 29

in a parallel circuit, the current flow is _______ to the resistance of the pathway

Answer 29

inversely proportional

Question 30

how is the total voltage calculated in a parallel circuit

Answer 30

sum of voltages at each resistance component

Question 31

explain tissues most heated in contraplanar vs co-planar capacitive diathermy

Answer 31

contra = tissue with greatest resistance (fat/skin) co = tissue with least resistance (cutaneous skin)

Question 32

how many plates are in capacitive diathermy

Answer 32

2

Question 33

explain how capacitive plates work

Answer 33

high frequency alternating electric current flows from one plate to another through body tissue

Question 34

how is heat generated in the body via capacitive plates

Answer 34

current flow through tissue will cause charged particles to oscillate and generate heat

Question 35

what is the down-side of capacitive plates?

Answer 35

fat and skin heat the most rather than muscle

Question 36

explain how distance between capacitive series in parallel can affect tissue heating

Answer 36

closer that the capacitive heads are, the more superficial the heating further = deeper heating

Question 37

how does magnetic field change affect electrical fields

Answer 37

one changes, the other changes as well

Question 38

explain tissue penetration of inductive diathermy

Answer 38

tissue of least resistance 2-3 cm penetration if fat at treatment site is <2cm

Question 39

types of electrodes used in inductive diathermy

Answer 39

cable or inductive coil mono or dipole drums

Question 40

explain the process of inductive diathermy

Answer 40

alternating current flowing through coil produces perpendicular magnetic field that induces electrical eddy currents in the tissue

Question 41

when particles oscillate in the body, what occurs

Answer 41

increased friction and heating

Question 42

what determines the amount of heat generated in inductive therapy

Answer 42

intensity of magnetic field via distance of applicator from body strength of eddy currents via body tissue type

Question 43

explain heating depth of inductive vs capacitive plates

Answer 43

inductive = deeper

Question 44

physiological effects of diathermy

Answer 44

vasodilation improve wound healing increase collagen elasticity decrease pain

Question 45

time period associated with thermal effects of diathermy

Answer 45

20 min

Question 46

indications for diathermy

Answer 46

non-acute MSK injury OA non-acute RA improvement of blood flow soft tissue healing increased metabolism decreased muscle spasm/guarding joint stiffness/contractures trigger points/neuralgia pain

Question 47

advantages of diathermy

Answer 47

heats deeper tissues than other superficial heating agents cover a larger area than US Shortwave does not reflect from bone do not have to maintain direct contact with patient for treatment

Question 48

diathermy application steps

Answer 48

clean area apply toweling to treatment area align plates close to skin w/o touching turn heat intensity to proper level duration of 15-20 for lasting effect of 20-30 min

Question 49

contraindications for diathermy

Answer 49

epiphysis of growing bones metal in area implanted neural stimulators pacemakers sensory disturbances at area infection / malignancy or neoplasia / fever / active bleeding therapist or patient pregnancy

Question 50

precautions of diathermy

Answer 50

external electronic devices epileptic seizures sensory disturbances obesity

Question 51

documentation of diathermy

Answer 51

area treated type of diathermy position intensity duration pre and post assessment