The Lighting is not important for scanning since different wavelengths are used and not different types of lamps.  It is however important for examining external organs, for example skin and the detection of skin cancer.  To detect skin cancer it is necessary to illuminate the skin so lamp choice is very important.

Lamp Choice
 Influenced by many factors
Wavelength required
Intensity required
Area to be illuminated
Objects reflectivity
Available Space
Transmission Efficiency
Ac or DC supply source
Safety
Types of Lamps
Incandescent Bulbs
Common household bulb
A lot of infrared
Simple source but can cause shadows

Fluorescent

Cheap diffuse light source
Minimises the amount of shadow
Mains flicker
High frequency version available

Tungsten Filament

Low intensity point source
Found in interior display lights

Quartz Halogen

High intensity point source
Found in shops
Used in car headlights

Light Emitting Diodes (LED'S)

Long life, even, low intensity beam
But not strictly a lamp

Xenon arc discharge

High intensity
Used in strobe lights
Short lifetime
Dangerous ( high Wattage/ Photosensitive epilepsy)
Lighting Techniques
Strobe Light - used at discos
Freezes moving objects
Must synchronize with camera
Dangerous
Short Life (3 - 6 months)
Stability/ consistency of flash
Factors That affect Reliability
Variations due to ageing - Intensity and Colour variations
Mechanical stability of filament
Effects of foreign material (oil, dirt) on output
Variations in the intensity when servicing or changing of the lamps occur.