laser and its application in biology,its a simple presentation which give a simple over view about lasers and its application in biology

1. Sasna.p.s
Laser & Its
Applications in
Biology

2. What is a Laser ?
 A laser is an amplifier which emits electromagnetic
energy in the form of a concentrated light beam.
 LASER –Light Amplification by Stimulated Emission
Of Radiation
 Based on the principle of stimulated radiation by
Einstein in 1917.
 A laser differs from other sources of light because it
emits light coherently.
 Spatial coherence allows a laser to be focused to a tight
spot.

3. Charles H. Townes (left), winner of the 1964 Nobel Prize for Physics,
and associate James P. Gordon in 1955 with the first maser (
Microwave amplification by stimulated emission of Radiation)

4. Laser principle
 If a few photons of energy E(excited state energy)
– Eo (ground state energy ) are introduced these
immediately stimulate the emission of a number
of photons of the same kind.There is a increase in
number of photons and theses again stimulate the
emission of more photons .In this way a chain
reaction is formed and as a result all the atoms
present give up their photons rapidly .
 This process is called laser action or light
amplification by stimulated emission of radiation
as the original pulse of photons has been
amplified in to a more powerful pulse of light .

5. Nature of laser light
 Monochromatic light ( all Photons have same energy
above the ground level, same frequency ,single wave
length )
 Coherent light (all photons or waves in phase )
 Unidirectional light (emitted waves are parallel )
 High intensity

6. Ruby laser beam
 First successful development of laser (1960)
 Ruby crystal ( aluminium oxide with a chromium
impurity)
 Laser beam is produced by exciting the molecules of
ruby crystal .
 Molecules of ruby crystal then emit a characteristic red
light and excite neighbouring molecules and process
continues like a chain reaction.
 Both ends are silvered which keeps on reflecting and
thus amplifying intensity of light (one end is partially
silvered )
 Sides are kept free to allow light from pumping lamp
 Powerful beam of red light emerges through a section
at one end of ruby crystal which is only partially
silvered .

8. Types of Lasers
(medical use)
Argon
Argon/Krypton
Tunable Dye
Yttrium-Aluminium –Garnet
(YAG )

9. Mechanism of lasers
 Photocoagulation (thermal lasers)
 Photo Disruption(cutting effect on Tissues)
 Photo Evaporation(carbon dioxide laser) -long
wavelength IR heat beam
 Photo decompostion-Excimer laser (breaks chemical
bonds of biological materials, very short wavelength)

10. Application of laser beam
Diagnostic
Therapeutic
Surgical

11. Diagnosis
 Ultrasensitive analytical methods To detect even a single
atom or molecule (metabolic study & Toxicology)
 To localize early lung cancer
 Laser beam exhibits Fluorescence pattern difference b/n
normal and atherosclerotic vessels ( Vascular surgery)
 Fiber optic endoscopy( can be focused to internal organs
 Holography (3 dimensional photography)
 Measurement of capillary blood flow

12. Surgeries such as laser-assisted in situ keratomileusis (LASIK)
are aimed at reshaping the tissues of
the eye to correct vision problems in people with particular eye
disorders, including myopia and astigmatism.

13. Therapeutics
 Phototherapy of neonatal jaundice ,cancer & various
skin diseases
 Cancer photo chemotherapy( laser beam can be
focused to internal organs which helps for single
administration of therapeutic dose In the organ)

14. In the standard form
of phototherapy, baby
lies in a bassinet or
enclosed plastic crib
(incubator) and is
exposed to a type of
fluorescent light that
is absorbed by baby's
skin.
During this process,
the bilirubin in the
baby's body is changed
into another form that
can be more easily
excreted in the stool
and urine.
Phototherapy doesn't
PHOTOTHERAPY

15. Photodynamic therapy (PDT) fiber optic surgery
photosensitive drug absorbed by cancer cells can be
activated by a laser beam guided through optical fibers to
selectively destroy a tumour.

16. Surgery
 Proliferative Diabetic Retinopathy (Photocoagulation)
 Treatment of Glucoma( to open up Blocked canals-
Microsurgery )
 Microsurgical Technique for alteration of structure at
sub cellular level.
 Microsurgical technique For genetic study

17. DIABETIC RETINOPATHY

18. Other uses in Medicine
 Surgical removal of tumours in selected cases
 Endoscopic diagnosis for early malignancy
 Laser knife for reduction in blood loss & pain
 Cosmetic surgery(facial wrinkles & deep scars)
 Holmium cold laser (alternative to bypass surgery and
angioplasty )
 Copper vapour laser (vascular disorders )
 Holmium laser (orthopedic surgery )
 Nd:YAG laser (for approaching difficult recesses of the
mouth remaining painless & no local anaesthesia)
 Uv excimer Lasers (Treatment of rootcanal )
 Eye therapy

19. ROOT CANAL TREATMENT

20. Glucoma Treatment
 The laser beam (a high energy light beam) is focused
upon the eye's drain. The laser does not bum a hole
through the eye. Instead, the eye's drainage system
is changed in very subtle ways so that aqueous fluid
is able to pass more easily out of the drain, thus
lowering IOP (intraocular pressure)

21. Advantages
 The unique Properties of laser light allow the beam to
be focused down to extremely small spots resulting in
very high energy densities that are the basis of the
tissue altering effects.
 Patient compliance increases because of Reduced
hospital stay.
 A safer & quicker alternative to surgery.
 Serious ocular diseases can be treated.
 Effective therapeutic modality is offered by
experienced surgeon.