الفهرس 
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Abstract
Neonatal jaundice, the yellow coloration of the sclera and skin caused by hyperbilirubinemia, is one of the most common conditions confronting neonatologists daily. About 60% of term and 80% of preterm infants develop jaundice in the first week of life (Rennie , et al., 2011)
Fortunately, a noninvasive and easily available treatment, neonatal phototherapy is effective in degrading unconjugated bilirubin. Following the discovery of phototherapy in the 1950s, many clinical trials have addressed its application to neonatal jaundice (Hansen .,2010 )
As phototherapy treatment has developed through the years, It has almost completely replaced exchange transfusion because of the efficacy and safety of the treatment (de Carvalho et al, 2011)
Phototherapy reduces serum bilirubin levels by converting bilirubin through structural photo-isomerization and photo-oxidation into execrable products. The principal sites of phototherapy action may localize not only in the skin but also in capillary circulation under the skin (Tao Xiong et al ,2011)
The efficacy of phototherapy in reducing total serum bilirubin (TsB) depends on several factors
(1) The level of initial bilirubin level
(2) Area of skin exposed. Body surface area exposed to phototherapy determines the efficacy. Therefore, babies exposed to double surface phototherapy are reported to have faster decline of bilirubin levels.
(3) The dose of light (measured as irradiance x duration of treatment x % body surface area treated).
There is a dose-response relationship; with increasing dosage of light, the fall of bilirubin is faster. The rate depends on the spectrum of light delivered and the irradiance, which is affected by the distance of light source from the baby. The farther the phototherapy unit is from the patient, the less will be the irradiance delivered. Halogen lights should not be placed close to the baby as they deliver considerable heat. Light emitting diode (LED) lights emit little heat and, like fluorescent lights, can be brought close (up to 10 cm) to the baby. Increasing the surface area exposed can be achieved by using a light source above and below the infant or by placing reflecting material around the inside of the bassinette or incubator. (Maisels et al.; 2001)