01/27/2026
Just one of the MANY reasons we choose to use attended Class IV Laser over other Lasers.
We are the only Attended Class IV Laser in the Area and have been doing Class IV Therapy longer than anyone in the State.
The First Law of Photochemistry, the Grotthus-Draper Law states: "Only that light which is absorbed by a system can bring about a photochemical change." In other words, in order to undergo photobiomodulation, chromophores must absorb photons of light.
See the picture. The figure at left represents treatment with a class 3B laser, and a class 4 on the right. In the same 5 minutes of treatment time, the 3B laser gives 150 joules, and the class 4 laser 1500 joules. If the desired surface dosage is 5 J/cm2, then the 3B can only treat 30 square centimeters and the 4 can treat 300 square centimeters.
The areas shaded with red are being treated, are absorbing photons, and are undergoing photobiomodulation. If the pathology is directly under the three little red dots for the 3B treatment, then the patient may be helped. However, it's likely that all of the tissues in the shoulder (in this example) are affected. The entire 300 cm2 area is absorbing photons from the class 4 therapy laser.