Content Knowledge Expectations for Entry-Level PTA
- UV radiation is electromagnetic radiation with wavelength between below 290 nm and up to 400 nm, lying between x-ray and visible light. UV is emitted by the sun and by UV lamps. UV radiation is divided into three categories defined by wavelength. UVA has the longest wavelength (320 to 400 nm), UVB is in the middle (290 to 320 nm), and UVC has the shortest wavelength (less than 290 nm). UVA has the greatest depth of skin penetration, whereas UVC affects the most superficial skin layers.
- Effects of UV radiation include erythema, tanning, epidermal hyperplasia, and vitamin D synthesis. UVC may be bactericidal, whereas UVA and UVB can affect immune activity and inflammation, depending on the dose applied.
- UV is used primarily for the treatment of psoriasis and other skin disorders. UVB or UVA in combination with psoralen (PUVA) are preferred. UVB is gaining popularity for this application because it has fewer side effects than PUVA alone, is easier to apply, and is almost as effective as PUVA alone. UVC is sometimes used to augment standard wound care interventions in patients with chronic wounds.
- Contraindications to the use of UV radiation include irradiation of the eyes; skin cancer; pulmonary tuberculosis; cardiac, kidney, or liver disease; systemic lupus erythematosus; and fever. Precautions include photosensitizing medication use, photosensitivity, and recent x-ray therapy. No dose of UV radiation should be repeated until the effects of the previous dose have disappeared.
- Changes in skin pigment that have not been diagnosed may indicate and autoimmune disorder or tissue trauma. Any changes in skin pigment or a new onset of irregular skin appearance should be reviewed with the supervising physical therapist.
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