V-254: Hot or Cold Quartz?

Neither.

This is a term used prior to the advent of superior lighting technology using fluoresecent bulbs.

Historically the state of art was to use what was referred to as a "hot/cold quartz" lamp for producing ultraviolet energy in the 254 nanometer range. The "hot" vs. "cold" discussion was about waiting for the lamp to get "hot" which meant a time period before maximum efficiency of emission of ultraviolet energy occurred. During the "cold" period it was advised to not treat the patient as not enough UV energy was coming out of the unit. When it reached it's "hot" period, generally 1 - 2 minutes after turning on, then the physical therapist( UV PT)would begin treatment of the patient's wounds.

The V-254 uses mercury vapor bulbs and there is not a "warm up period" and treatment begins as soon as the lamp is turned on.

For an explanation of how the mercury produces the energy go to:

http://howthingswork.virginia.edu/page1.php?QNum=516