<s>[INST] context: Heat therapy 

Heat therapy is a form of physiotherapy used in many painful conditions eg. arthritis, sprains, muscle spasms etc.
It is of 2 types depending on the penetration of heat



Superficial heat therapy
Deep heat therapy

A) Superficial heat therapy

Only the skin and subcutaneous tissues are heated
Superficial heating modalities do not heat deep tissue because the subcutaneous layer of fat beneath the skin surface acts as a thermal insulator and inhibits heat transfer.
Superficial heating modalities include :


Hot warm bottle                                                                                                      
Warm bath                                                                                                              
Hot packs (eg. Kenny pack)
Hot soaks or compresses
Paraffin wax bath                            
Moist air cabinet
Chemical packs
Infrared lamp

B) Deep heat therapy

Deeper structures (including muscles) are heated
In general, the transfer of heat is of three types- conduction, convection & conversion (or radiation)
Whereas superficial heating modalities use all three modes of transfer of heat; deep heating modalities use only conversion or radiation method to heat the deep tissues.
Deep heating modalities are

a) Shortwave diathermy

Heat generated by high-frequency alternating current using a shortwave diathermy emitter.

b) Microwave diathermy

This uses electromagnetic radiation energy to heat the deep tissues

c)   Ultrasound therapy

Uses high-frequency sound energy [/INST] question: Which is not a deep heat therapy- | options: A: Short wave diathermy B: Ultrasound therapy C: Infrared therapy D: Microwave therapy | answer: C </s>