PT- High Freq generators Flashcards
shortwave diathermy reaches how deep into the body
2 inches into muscle
- puts out the most heat
freq and wave length of shortwave diathermy
freq: 27.12MHz
wavelength: 11 meters
____: middle and high freq. generators cant depolarize, bc the freq is to high and never leaves the refractory period
Wedensky inhibition
___ law: the denser the structure the mroe resistance there is = more heat needed
Kirchoff’s law
High freq modalities need to be used with more resistant strutures: thicker M / more fibrous tiss
___: a burn to the skin with diathermy
how can this happen?
edge effect
occurs when:
- no towel used
- allow the electrodes to be closer then 1 in
- wires cross each otehr
EM-SWD vs. ES-SWD
EM-SWD: (induction), electromagnetic
- uses: vascular
- No adipose effect - use on obese
ES-SWD: (codenser) electrostatic
use: deep cavities, bronchitis, pelvic cavity
- has adipose effect
___ rule: anything electronic needs to stay away from diathermy
4 foot rule
indications for diathermy (4)
- upper/ lower respiratory conditions
- sinusitis
- otitis externa
- vaginitis / prostatitis
(3) contraindications for diathermy
- IUD
- Contact lens
- pacemaker
“reverse piezoelectric effect”
US diathermy
what is the mechanism of the reverse piezoelectric effect in US
takes electrical NRG and changes it to mechanical NRG
what is the MC crystal used, and the best crystal to use when doing US
MC: Barium titanate
best: Quartz sulfate
____: surface area of the crystals, only tx about 2-3x the the size of the crystal
Effective radiating area (ERA)
_____ (US): how much surface area of the NRG going into the ST is smooth and even
- 2:1: best
- 6:1: worst that can still be used (periosteal burn with higher)
Beam non-uniformity ratio (BNR)
__: burn from US
shear effect
