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Flashcards in UVR Deck (55)
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1

bands of UVR

UVA,B,C

2

among three bands of UVR which has the longest wavelength

UVA

3

UVA wavelength

320-400 nm

4

UVB wavelength

290-320 nm

5

UVC wavelength

<100-290 nm

6

other name for UVA, B and C

A: long wave; near
B: middle wave
C: short wave, far

7

Frequency: ranges from

1.65 x1015 to 7.5 x 1014

8

Wavelength: shorter than --, longer than --

visible, x-ray

9

use of UVA

blacklight

10

use of UVB

skin erythema; sunburn

11

UVC use

germicidal and bacterial purposes

12

Method of transmission:

radiation via phototherapy
UV is not visible to us but we can feel it
Photochemical effect

13

Possibilities:

Reflected, refracted, absorbed
Absorbed within 1-2mm (0.22) mm of human skin
80-90% absorbed in the dermis

14

UV produces heat?

no

15

UV is both --ing and --ing

UV is both ionizing and non-ionizing

16

what can happen if wrong dosage is applied

Cutaneous malignant melanoma
Basal cell carcinoma
Squamous cell carcinoma

17

Factors affecting penetration

Intensity => directly related
Wavelength => directly related
Power of radiation source => direct
Exposure duration => direct
Distance of radiation => inverse
Frequency => inverse
Size => inverse
Thickness => inverse
Pigmentation of skin => inverse

18

equipment

Mercury arc
Fluorescent

19

Mercury arc lamps:

Small
Emit radiation at constant intensity
Used for smaller areas
Types:
Hot quartz
Cold quartz

20

Fluorescent lamps

Long
Emit higher-intensity radiation
Used for larger areas
Low pressure mercury discharge tubes with phosphor coating inside (theraktin)

21

hot quartz

burner w argon gas and mercury

high pressure and temp

c erythema and pigmentation

applied >15 inches form area

no need for warm up

22

cold quarts

cold quartz with mercury (ionized vapor)

dec pressure and temp

minimal erythema and no pigmentation

applied at close proximity

needs 5 min warm up

23

physiological effects

erythema production
delayed pigmentation of skin
thickening of superficial layer of skin
vit d synthesis
bactericidal effect

24

Erythema production

Vasodilation of vessels
Happens because of histamine and prostaglandin release
Exposure to UVB or UVA after drug sensitization
Practical application: proper dosage

25

Delayed pigmentation of skin

Production and upward migration of melanin
Oxidation of pre melanin
Tanning = less penetration
Practical app: examine skin phototype of patients

26

Thickening of superficial layer of skin

Thickening of epidermis due to cell proliferation
72 hrs after exposure to UVR
Practical app: progressive higher dose for thicker skin

27

Vitamin D synthesis

Converts inactive provitamin D to become active vit D
Activates inactive vit D
Effective treatment for psoriasis
Practical application: for psoriasis

28

Bactericidal effect

UVC = bactericidal affect
Promotes wound healing
Desquamation => slough off dead skin cells
Practical app: bactericidal effect in open wounds

29

irradiance (I)

intensity or power density

measured by uv sensor on device

mw/cm2

30

dose per treatment time (Dt) =

I X T