three

1. i
WOLAITA SODO UNIVERSITY
COLLEGE OF NATURAL AND COMPUTITIONAL SCIENCE
DEPARTMENT OF PHYSICS
REVIEW ON APPLICATION OF LASER IN MEDICINE
A SENIOR PROJECT SUBMITTED TO THE DEPARTMENT OF PHYSICS IN
PARTL FULFILLMENTEQUIREMENTS OF THE DEGREE OF BACHELOR
SCIENCE IN PHYSICS
BY: - MOHAMED TERECHA
ID No :. PHY/SUM/1469/2008E.C
ADVISOR: - Kuse G (Dr)
August 2021
Wolaita Sodo, Ethiopia

2. ii
Acknowledgement
First of all I should offer my thanks obedience and gratitude to God. I would also like to extend
my sincere thanks and appreciation to my great supervisor Dr.Kuse for his valuable guidance
assistanc
e and help that enable me to complete my Project.
Very special thanks to the Wolaita Soddo University, to all my Friends and for Natural Sciences
family.
Last but not least, special thanks to my parents, the Rest of my family and my for their great
encouragement and support.

3. iii
Abstract
This work gives an idea about the originality of laser beams and how We benefit from them in
the treatment and the recovery of patients. Some of the important medical lasers are
Neodymium-YAG Laser (ND: YAG) is used in laparoscopic surgery, the Carbon Dioxide Laser
(CO2) is one of the most widely used in surgical operation especially in Gynecologic surgery.
Moreover it’s used as scalpel, the Argon Laser (Ar+) is used for ophthalmology and the Dye
Laser is recently used in the Treatment of cancer tumor.
We know that Argon and Dye Lasers beams produce intense visible light that can be seen by the
naked eye. For this reason they can be easily controlled and directed by the surgeons’ and
physician. But beams of Carbon Dioxide and YAG Lasers are invisible and they are located in
the
Zone of the infrared region.
For this reason we use the beams of Helium Neon lasers that have red color with energy very
low. So we use these Lasers simultaneously with the above mentioned lasers beams to allow the
operator to adjust spot size and operation distances efficiently.
This enables the surgeons and physicians to accomplish more serious operations and to obtain
more satisfactory results.

4. iv
Contents
Acknowledgement ...............................................................................................................................ii
Abstract............................................................................................................................................. iii
CHAPTER ONE .....................................................................................................................................1
Introduction........................................................................................................................................1
Background of study ............................................................................................................................1
1.1.1. ELECTROMAGNETIC WAVE .......................................................................................................1
1.1.2. THE LASER SPECTRUM AND WAVELENGTH.................................................................................2
1.2. STATEMENT OF THE PROBLEM ....................................................................................................2
1.3 OBJECTIVES OF THE STUDY...........................................................................................................2
1.3.1 GENERAL OBJECTIVES............................................................................................................2
1.3.2 SPECIFIC OBJECTIVES.............................................................................................................3
1.4. SCOPE OF THE PROJECT...........................................................................................................3
1.5. LIMITATIONS OF THE PROJECT ............................................................................................3
CHAPTER TWO ....................................................................................................................................4
2. REVIEW OF LASER.............................................................................................................................4
2.1 DEFINITION OF LASER..................................................................................................................4
2.2 PRINCIPLE OF LASING ACTION ......................................................................................................5
2.3 TYPES OF LASERS ........................................................................................................................5
2.3.1 GAS LASERS: HELIUM-NEON (HE-NE) LASER: ............................................................................5
2.3.2 ARGON AND KRYPTON ION LASER ..........................................................................................5
2.3.3 CARBON DIOXIDE LASERS ......................................................................................................6
2.3.4 DYE LASERS..........................................................................................................................6
2.3.5 SOLID STATE LASERS: RUBY LASERS.........................................................................................6
2.3.6 NEODYMIUM YAG LASER.......................................................................................................7
2.3.7 YTTERBIUM YAG LASER .........................................................................................................7
2.3.8 SEMICONDUCTOR LASER .......................................................................................................7
2.3.9 QUANTUM CASCADE LASERS .................................................................................................7
CHAPTER-3..........................................................................................................................................8
3. METHODS USED IN THE PROJECT .......................................................................................................8
3.1. PROPERTIES OF LASERS...............................................................................................................8
3.2. IDENTIFICATION OF SAFETY MEASURES ........................................................................................8
3.3. APPLICATION OF LASER IN MEDICINE .........................................................................................10

5. v
3.3.1 The Neodymium: YAG Laser: ................................................................................................10
3.3.2 The Argon - Laser:...............................................................................................................10
3.3.3The Carbon - Dioxide Laser: ..................................................................................................11
3.3.4 The Dye Laser:....................................................................................................................11
3.3.5 Dermatology:.....................................................................................................................12
Chapter Four .....................................................................................................................................13
Conclusion ........................................................................................................................................13
References........................................................................................................................................14

6. 1
CHAPTER ONE
Introduction
Background ofstudy
The word laser is an acronym for Light Amplification by the Stimulated Emission of Radiation.
Laser light today covers a wide range of wavelengths, which includes the visible range of the
electromagnetic spectrum (1).
Light Amplification by the Stimulated Emission of Radiation was originally described as a
theoretical concept by Albert Einstein in 1917, but it was not until 1954 that the first
"stimulated" emissions of microwave radiation (Maser) were generated by J.P Garden and C.H.
Townes at Bell Laboratories. Theoretical calculations for the construction of a visible light
Maser or Laser were published in 1958. The first Laser was built in 1960 by T.H. Maimane. His
laser consisted of a pink ruby rod with silvered ends for mirrors inserted in a helical coil of a
photographic flash lamp, which generated millisecond pulses of coherent 694nm Ruby Laser
(red) light (2).
Today lasers have entered almost all fields of science and have made a wide step of progress in
many of them. Laser has become the modern technique of the 20th century. In medicine, it
became the "beam that heals" and has been utilized in nearly every discipline of medicine, in
diagnosis, therapy, surgery and medical instrumentation.
In order to realize the full advantages of using a laser beam, one should understand the process of
interaction between the beams one uses and the spot one needs to treat. One should know
something about beam properties, its origin and the requirements needed to provide such a beam;
also one should know how to handle the laser system and how to work safely, with an awareness
or all possible hazards and, therefore, taking all necessary precautions to avoid harm to oneself
and damage to treated area .
1.1.1. ELECTROMAGNETIC WAVE
Electromagnetic wave is produced by electric and magnetic wave, the speed all electromagnetic
wave is (c=3×108m/s).these waves discovered by famous physicist James Maxwell. They can be
defined as “when electric and magnetic fields fluctuate together they leads to formation of the
propagating waves called electromagnetic waves”.

7. 2
Electromagnetic waves propagate both in medium and vacuum are the meaning of the middle
state between two extremes and a space from which the air has been removed, respectively.
According the visibility of the electromagnetic wave is white ,the range between violates up to
red or 400nm to 700nm and the invisible electromagnetic waves are gamma rays ,x-rays, UV-
radiation ,infrared ray, micro waves and radio waves.
The speed of electromagnetic wave is C==2.998×108m/s
Where is magnetic permeability 10-7 =8.85x10-12
1.1.2. THE LASER SPECTRUM AND WAVELENGTH
There are several types of units that are used to define laser wave lengths. These range from
micrometer or microns (mm) in the infrared to nanometer (nm) and Angstrom (A) in the visible,
ultraviolet (UV), vacuum ultra violet (VUV). The relationship between energy and frequency or
wavelength is:
E=hf,
E=; the decreasing wave length is in increasing energy and the longer wave length the
lower frequency.
1.2. STATEMENT OF THE PROBLEM
Laser is related to the scientific applications which used community in multi-directional aspects
some of them are defense, peoples may look the positions of enemies where they attack
themselves to block that areas by using laser. Medical application, before this instrument doctors
use surgical appliances but in that case many people may die due to some errors and electrical
problems but this laser strictly ahead over position of particular place which the sickness belongs
and also welding and cutting, surveying and ranging, Garment industry and communication are
the most place where these laser gives effective and scientific uses to the community.
Therefore our target is to create awareness to the community in physics department and widely
use laser throughout the community.
1.3 OBJECTIVES OF THE STUDY
1.3.1 GENERAL OBJECTIVES
The aim of this project is members of the project will have detailed understanding of the laser.

8. 3
The general objectives of this project is to enable the project members have detailed
understanding of laser.
1.3.2 SPECIFIC OBJECTIVES
The specific objectives of this project are:
To summarize the advantages and disadvantages of laser
To state the applications of laser in medicine
To explain about safety measures related to laser
1.4. SCOPE OF THE PROJECT
This senior project paper is a partial fulfillment of the requirement of the degree of bachelor
science in physics at Wolaita Sodo University department of physics. In addition its contribution
to the scientific community is little and it can be a starting point for future research activities.
1.5. LIMITATIONS OF THE PROJECT
Shortages to enhance this project are material scarcity, references, computer and living in remote
and rural areas. Shortage of enough knowledge and its application and familiarities with laser
light in our surroundings and educated persons in the areas of this subject for constructive
suggestions. Economic and financial shortage, to promote flexible works for computer use,
transportation, lunch and tea and other financial break downs.

9. 4
CHAPTER TWO
2. REVIEWOFLASER
2.1 DEFINITION OF LASER
A laser is a device that emits electromagnetic radiation through a process of optical amplification
based on the stimulated emission of photons. Lasers are a device that produces intense beams of
light which are monochromatic, coherent and highly collimated. The wave length of laser light is
extremely pure when compared to other sources of light and all of the photons that make up the
laser beam have a fixed phase relationship with respect to one another. Light from laser light
typically has very low divergence.it can travel over larger distance or can be focused to a very
small spot with brightness which are used in a wide variety of application in all walks of life. A
basic understanding of the theory helps in understanding the laser device.
Electromagnetic radiation is emitted whenever a charged particle such as an electron gives up
energy. This happens every time an electron drops from a higher energy state, Qs, to a lower
energy state, Qu, in an atom or ion as occurs in a fluorescent light. This also happens from
changes in the rotational state of molecules. The color of light is determined by its frequency or
wavelength. The shorter wavelengths are the ultraviolet and thelonger wavelengths are the
infrared. The smallest particle of light energy is described by quantum mechanics as photons.
Laser is a powerful source of light having extra ordinary properties which are not found in the
normal light sources like tungsten lamps, mercury lamps etc. The unique property of laser is that
its light waves travel very long distances with a very little divergence.in case of a conventional
source of light, the light is emitted in a jumble of e separate waves that cancel each other at
random and hence can travel very short distance only.
Emission of radiation from an atomby transition of an electron from a higher energy state to a
lower energy state.an analogy can be made with a situation where a large number of pebbles are
thrown it into a pool at the same time. Each pebble generates a wave of its own. Since the
pebbles are thrown at random, the waves generated by all the pebbles.

10. 5
2.2 PRINCIPLE OF LASING ACTION
Every atom, according to the quantum theory, can have energies only in certain discrete states or
energy levels. Normally the atoms are in the lowest energy state or ground state. When light
from a powerful source like a flash lamp or mercury arc falls on a substance, the atoms in the
ground state can be excited to go to one of the higher levels. This process is called absorption
after staying in that level for a very short duration of the order of 10-8 second, the atoms returns
to its initial ground state emitting a photon in the process, this process is called spontaneous
emission. The two processes namely, absorption and spontaneous emission ,takes place in a
conventional light source, in case the atom, still in its turns to excited state ,is struck by an
outside photon having precisely the energy necessary for spontaneous emission ,the outside
photon is augmented by the one given up by the excited atom. Moreover both the photons are
released from the same excited state in the same phase, this process is called stimulated emission,
is fundamental for laser action. Thus, the atom is stimulated or induced to give up its photon
earlier then it would have done ordinarily under spontaneous emission. The laser is thus
analogous to a spring that is wound up and cocked, it needs a key to release in this process and
figure-3 shows the basic energy level diagram of lasers.
2.3 TYPES OF LASERS
2.3.1 GAS LASERS: HELIUM-NEON (HE-NE) LASER:
He-Ne laser is the most widely used noble gas laser. Lasing can be achieved at many wave
length 632.8nm.pumping is achieved by electrical discharge. The helium is excited by an
electron impact. The energy is then transferred to Neon by collisions. The first He-Ne laser
operated at the 1.1523nm line 7.He-Ne lasers are used in many applications such as
interferometer, holography, spectroscopy, bar code scanning, alignment and optical
demonstrations.
2.3.2 ARGON AND KRYPTON ION LASER
Similar to the He-Ne laser an Argon ion gas laser is pumped by electric discharge and emits light
at wave length 488.0nm ,514.5nm,351nm,465.8nm,472.7nm,and 528.7 nm. It is used in
applications range from scientific research when mixed with Argon it can be used as “white
light” lasers for light shows.

11. 6
2.3.3 CARBON DIOXIDELASERS
In the carbon dioxide (Co2) gas laser the laser transitions are related to vibration-rotational
excitations. Co2 lasers are highly efficient approaching 30%.the main emission wave lengths are
10.6nm and 9.4nm.
They are pumped by transverse or longitudinal electrical discharge.it is heavily used in the
material processing industry for cutting and welding of steel and in the medical area for surgery.
Carbon monoxide (CO) gas lasers are having wave length ranging 2.6nm-4nm; 4.8nm-8.3nm and
they are pumped by electrical discharge. They are used in material processing such as engraving,
welding and in photo acoustic spectroscopy. Output powers as high as 100kw have been
demonstrated: chemical lasers emitting in the UV: 193nm (ArF), 248nm (KrF), 308nm (XeCl),
353nm (XeF) excimer.
These are molecules that exist only if one of the atoms is electronically excited. Without
excitation the two atoms repel each other. Thus the electronic ground state is not stable and is
therefore not populated, which is an ideal for laser operation. These lasers are used for ultraviolet
lithography in the semiconductors industry and laser surgery.
2.3.4 DYE LASERS
The laser gain medium is organic dyes in solutions of ethyl, methyl alcohol, glycerol, or water.
These dyes can be excited by optically with Argon lasers, for example and emit at 460nm-515nm,
570nm-640nm and many others.
These lasers have been widely used in research and spectroscopy because of their tuning ranges.
Unfortunately, dyes are carcinogenic and as soon as tunable solid state laser media became
available dye laser became extinct.
2.3.5 SOLID STATE LASERS: RUBY LASERS
The first laser was indeed a solid-state laser is ruby and is emitted at 694.3nm.ruby consists of
naturally formed crystal of Aluminumoxide (Al2O3) called corundum.in that crystal some of
Al3+ ions are replaced by Cr3+ ions.it is chromium ions that give ruby the pinkish color.i.e. Its
fluorescence, which is related to the laser transitions. Today,for the manufacturing of ruby as a
laser material artificially grown crystal form molten materials which crystalizes in the form of

12. 7
sapphire is used. The life time of the upper laser level is 3ms.pumping is usually achieved with
flash lamps.
2.3.6 NEODYMIUM YAG LASER
Neodymium YAG consists of yttrium-Aluminum-Garmet(YAG) Y3Al5O12 in which some of
the Y3+ ions are replaced by Nd3+ ions. Neodymium is a rare earth element, where the active
electronic states are shielded inner 4f states.Nd:YAG is a four level laser. The main emission of
Nd:YAG is at 1.064nm.
2.3.7 YTTERBIUM YAG LASER
Ytterbium YAG is a quasi-three level emitting at 1.030nm.the lower state laser level is only
500cm-600cm above the ground state and is therefore at room temperature heavily thermally
populated. The laser is pumped at 941 or 968nm with laser diodes to provide the high brightness
pumping needed to achieve going.
2.3.8 SEMICONDUCTOR LASER
An important class of solid state laser is semiconductor lasers. Depending on the semiconductor
material used the emission wavelength can be further refined by using band structure engineering,
0.4nm (GaN) or 0.63-1.55nm (AlGaAs).in GaAs,inGaAsp) or 3-20nm(lead state).The AlGaAs
based lasers in the wavelength range 670nm-780nm are used in compact disc players and
therefore are the semiconductor laser the electronic band structure is exploited ,which arises from
the periodic crystal potential 10.
2.3.9 QUANTUM CASCADE LASERS
A new form of semiconductor lasers was predicted in the 70’s by the two Russian physicists’
kazarinov.

13. 8
CHAPTER THREE
3. METHODS USEDIN THE PROJECT
In order to meet the objectives of this project, members of the project have read different
materials to get detailed information about
Properties of laser light
A safety measures
Catastrophes of laser light
Common mistakes observed while using laser light for medical applications
The advantages and disadvantages of laser light
The principles to be used while applying laser light for different purposes
3.1. PROPERTIES OF LASERS
Monochromatically means “one color”.to understand this term, examine “white light” which is
the color interpreted in the mind when we see all colors together. When “white light” is
transmitted through a prism, it is divided into the different colors which are in it and laser
radiation does not have all those color, because it has only one same wavelength and phase and
monochromatic also means that laser has the high intensity of the light with in the very small
wavelength.so, it can have a high energetic level in microscopic region. Actually the temperature
of the laser radiation is higher than sun. Radiation comes out of the laser in a certain direction
and spreads at a defined divergence angle. This angular spreading of a laser beam is very small
compared to other sources of electromagnetic radiation and described by a small divergence
angle. Since, laser radiation divergence is of the order radians, which means almost negligible,
the beam is almost parallel and can be sending over long distances. So, laser radiation is highly
directional. Laser radiation is composed of waves at the same wavelength which start at the same
time and keep their relative phase as they advance. So, when two or more laser radiations can
make regular interference each other. So, laser radiation has a coherency.
3.2. IDENTIFICATION OF SAFETY MEASURES
Laser safety is the safe design, use and implementation of lasers to minimize the risk of laser
accidents, especially those involving eye inquiries. Since even relatively small amount of laser
light can lead to permanent eye inquires, the sale and usage of laser is typically subject to

14. 9
government regulations. Moderate and high power lasers are potentially hazardous because they
can burn the retina off the eye or even the skin.
To control the risk of injury various specifications, for example 2s code of federal regulations
(CFR) part 1040 in the US and IEC 60825 internationally, define “classes” of laser depending on
their power wavelength. These regulations impose up on manufacturers required safety measures
such as labeling lasers with specific wearing, and wearing laser safety goggles when operating
lasers. Consensus standards such as American National Standards Institutions (ANSI) Z 136
provide users with control measures for laser hazards as well as various tables helpful in
calculating maximum permissible exposure (MPE) limits and accessible exposure limits
(AELS).many scientists involved with lasers agree on the following guidelines.
Everyone who uses a laser should be aware of risks. This awareness is not just a matter of
time spent with lasers-: to the contrary, long term dealing with invisible risks (such as
from infrared laser beam) tends to reduce risk awareness primarily due to complacency
rather than to sharpen it.
Optical experiments should be carried out on optical table will all laser beams travelling
in the horizontal plane only and all beams should be stopped at the edge of the table.
Users should never put their eyes at the level of the horizontal plane where beams are in
case of reflected beams that have the table.
Watches and other jeweler that might enter the optical plane should not be allowed in the
laboratory. All non-optical objects that are close to the optical plane should have a matter
finish in order to prevent specular reflections.
Adequate eye protection should always be required for everyone in the room if there is a
significant risk for eye injury.
High intensity beams that can cause fire or skin damage (mainly from class and
ultraviolet lasers) and that are not frequently modified should be guided through opaque
tables.
Alignment of beams and optical components should be performed at a reduced beam
power whenever possible.

15. 10
3.3. APPLICATION OF LASER IN MEDICINE
Laser of popular use in medicine are the Neodymium: YAG (solid-state) laser, the argon ion Ar+
(ionic gas) laser, the carbon dioxide CO2 (molecular gas) and recently the dye (liquid) laser. In
this chapter, we will demonstrate, for each type, the system operation and the characteristics of
its output. We will also give some medical applications for each & clinical laser applications.
3.3.1 The Neodymium: YAG Laser:
The laser output is in the near infrared spectrum at wavelength 1060 nm. It has a poor absorption
by blood, i.e. absorption coefficient, a = 4cm-1and is less absorbed by water (a~0.1 cm-
1) .Hence it can penetrate rather deep into the tissue and is transmitted through clear liquids. This
allows its use in the eye and other water-like filled cavities such as the bladder. The Nd: YAG
beam has a high degree of scattering upon impact with tissue.
The homogeneous zone of thermal coagulation and necrosis from the impact site but precise
control is not possible. The laser beam is also used to coagulate vessels up to about 4 mm in
diameter. These characteristics make the Nd: YAG laser an excellent tool for tissue coagulation
but very crude, unprecise tool for cutting due to tissue damage. For treatments sapphires tips,
diamond or quartz are used to improve precision and to allow better control to avoid excessive
tissue destruction. Major specialties of the laser use is in the treatment of menorrhagia, e.g.
uncontrolled bleeding from uterus. A laser fiber is passed into the uterus via a hysteroscopy to
coagulate the endometrium. The pulsive form of Nd: YAG output, i.e. the Q-switched and the
mode-locked form, has found a growing use in ophthalmology both for eye diagnosis and
treatment. Laser can differentiate between a faulty neural system and a disturbed optical system
of the eye. Thus a predictive ability is provided when considering operations such as cataract
removal, vitrectomy, corneal transplant and glaucoma surgery (1, 3)
3.3.2 The Argon - Laser:
The laser beam is visible as a bright blue-green light of wavelength 488-515 nm. It is better
absorbed by blood (a = 34 cm-1) than the Nd: YAG laser, but its absorption in water (a <
0.001cm-1) is less than of No: YAG laser. It is easily transmitted through clear aqueous tissues.
Certain tissue pigments such as chromogens, melanin and hemoglobin will absorb argon laser
light very effectively. This localization of heat generation will be a highly effective coagulator.
The first significant medical application of this selective absorption characteristic was in the
treatment of diabetic retinopathy in 1965. The argon laser light is absorbed by the retinal pigment
epithelium and the generated heat is then used to photocoagulate the retina. Dermatology and
plastic surgery are the other major areas of applications of argon laser therapy. The laser light is
more heavily absorbed by the pigmented tissue or pigmented lesion than by the surrounding
tissue. A valuable application is the treatment of port-wine stains.

16. 11
Like other power output lasers, the argon laser beam when focused to a very small spot (or when
its power is increased sufficiently), its power density is high enough ‘to result in vaporization of
the target. Medical argon ion lasers are of power as high as 15W.
3.3.3The Carbon - Dioxide Laser:
The laser emission is in the mid infrared wavelength of 10.6 µ m.
This range is heavily absorbed by water (a = 230 cm-1). The biological tissue is composed of
70% to 90% water and its absorption to CO2radiation is independent on the tissue color unlike
its absorption to argon ion laser light. Due to this high degree of absorption, most of the incident
energy is sharply absorbed i.e. having a very short penetration depth (~0.01 mm), limiting the
lateral damage of the tissue and leaving a very small zone of coagulation and necrosis. This
makes the CO2 laser a precise surgical instrument.
The major applications of CO2 laser is in cutting, vaporization and coagulation. A focused spot
of the laser beam will allow a precise cut (laser scalpel) leaving a dry bloodless areas of damage.
The depth of the cut is determined by the power density and the time of irradiation.
Dry incisions heal in much the same way as conventional wounds.
Vaporization can be performed with focused or defocused beams. It helps in removing tissue of
one cell layer at a time from its delicate structure.
When cutting, vessels up to 0.5 mm in diameter can be coagulated instantly; larger vessels can be
treated with a defocused beam. Precision welding of arteries for microsurgery and anastomosis
of small vessels and nerves can be achieved.
The CO2 laser has found widespread applications in medicine, including most of its branches i.e.
gynecology, otolaryngology, neurosurgery, plastic surgery, ophthalmology, and others.
3.3.4 The Dye Laser:
The dye fluorescence covers a broad spectrum of colors. The dye laser is used where a selective
absorption characteristics of tissue upon certain wavelength is required in therapy; for example,
in the treatment of port-wine stains, tattoos and other pigmented tissue.
Currently, dye laser is used in photo radiation therapy (PRT), a new possibility for cancer tumor
detection and treatment. This involves the use of a photosensitizing agent (tumor seeking agent),
such as
haematoporphyrin derivative (HPD) in combination with laser radiation.
As illustrated in Figure 2.11, diluted (HPD) is intravenously injected into biological system. It
spreads, but is selectively retained in tumor tissue after two to three days.
Another application of dye lasers involves the pulsed type. They have been used to
fragment gall-stones and kidney stones. These are typically microsecond pulses, emitting energy
50-100mJ at wavelengths in
The blue-green region. Laser radiation is delivered to the stone by an

17. 12
Optical fiber passed through one of the channels of an endoscope The laser
Lithotripter (stone breaker) have several advantages over the acoustic
Shockwave lithotripter currently used for kidney stones (1).
3.3.5 Dermatology:
Laser is already being successfully used for cauterization and local treatment of skin growths
and skin deformities.
Laser treatment provides two major advantages over conventional treatment in case of burn
injuries and skin grafting. They are:
(a) the area, which has been treated remains sterile and hence provides an
Ideal bed for immediate skin grafting.
(b) The blood loss is minimal.
Laser finds wide application in dermatology especially in the following
Areas:
(a) Homeostasis, which means stopping of bleeding.
(b) Removal of hair, tattoos, warty keratosis, cell carcinomas, freckles,
acne and various growths, both benign and malignant.
CO2 lasers have been used for treating skin tumours.
Another application of laser more specifically photo medicine, is in the surgical treatment of port
wine stains (PWS). A port wine stain is a defect in the skin, which is manifested by discoloured
or blotchy and darkened patches in the skin.
The most commonly used laser in the treatment of PWS is the pulsed argon laser (13).

18. 13
Chapter Four
Conclusion
The aim of this work is to show the different methods of the applications of laser in medicine.
Lasers are classified according to their active medium. Some of the
important medical lasers are; Neodymium-YAG Laser (Nd-YAG), Argon Laser (Ar+), Carbon
Dioxide Laser (CO2), and Dye Laser.
Laser has special properties that makes it more important and useful than many other substances
or instruments that are used in medicine. Some of its properties are, laser light has small
divergence of beam & it has high energy. It has proved its great ability and benefits in the
different fields of medicine especially surgery because it reduces blood loss due to the operation
cutting, and including most of its branches i.e. gynecology, ophthalmology, dermatology, and
others.
Moreover laser has short pulses of light. This reduces pain and yields more rapid recovery to the
patient.
As the laser beam is very tiny the damage in adjacent tissues is very limited.
In laser operations the surgeon uses few instruments. This enables the surgeon to have a clear
vision of the spot of the operation.
Laser operation causes no wounds so the patient can leave the hospital immediately after the
operation. Laser operations have become more
Efficient, perfect and accurate due to the application of the computer control.
The relationship between the different laser beams and the tissues depends on the properties of
the laser beam according to its wavelengths, and its intensity.
In general lasers have many hazards, some of the important hazards are: radiation, explosive,
electrical, and toxic hazards. Due to these hazards it is very important that all the safety
precautions requirements should be available in the hospital where the laser system is used.
These safety precautions are: laser instrument should only be used by qualified and experienced
technicians, surgeons and physicians. The laser instruments must be kept away from those who
misuse them. These instruments must
Be occasionally checked, tested and maintained.

19. 14
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3- Kaya Ball, “Lasers the Perioperative Challenge”, second Edition,
Published in Nabcy L. Coon, USA. 1995.
4- Steen W.M, “Laser Materials Processing” Second Edition, 1998
5- Robert A. Mayers, “Enclopedia of Lasers & Optical Technology”,
First Edition, Academic Press, 1991.
6- http://www.shorelaser.com/aboutlasermed.html.
7- Jeff. Hecht; “The Laser and Applications Layers “, Francis LTD London, 1971.
8- Jeff. Hecht; “Laser Guide Book”, contributing Editor printed bound by Donnelly and Son
Company 1986.
9- Orazio Svelto, “Principles of Lasers”, fourth edition, London, Springer business Media, Inc,
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