This document discusses laser applications in medicine. It begins by defining what a laser is and the basic concepts and theory behind how they work, including stimulated emission and population inversion. It then describes different types of lasers such as solid-state, semiconductor, dye, gas, and excimer lasers. Applications of high- and low-level lasers in medicine are discussed. Parameters like wavelength, power, intensity, and dosage are also covered. The document concludes by discussing laser tissue interaction and regulation of medical lasers.
(A) By active media
Solid state laser - crystal, or glass, doped with impurities, e.g. ruby laser, Ti:sapphire laser, semiconductor laser.
Gas laser - e.g. He-Ne laser, Ar+ laser, CO2 laser, N2 laser, HCN laser.
Dye laser - active medium: dye molecules in liquid solvent (sometimes in solids also).
(B) By mode of operation
CW
Pulsed
(C) By pumping and laser levels
3-level laser
4-level laser
This belongs to Physical Chemistry portion and it contains most of
things about laser working and principles.
By Aaryan Tyagi's Group
M.Sc. Applied Chemistry (1 Sem)
Amity University, Noida
Laser characteristics as applied to medicine and biologykaroline Enoch
Laser” is an acronym for light amplification by stimulated emission of radiation. A laser is created when the electrons in atoms in special glasses, crystals, or gases absorb energy from an electrical current or another laser and become “excited.”Characteristics ,working ,types and application of lasers exclusively in medicine and biology.
(A) By active media
Solid state laser - crystal, or glass, doped with impurities, e.g. ruby laser, Ti:sapphire laser, semiconductor laser.
Gas laser - e.g. He-Ne laser, Ar+ laser, CO2 laser, N2 laser, HCN laser.
Dye laser - active medium: dye molecules in liquid solvent (sometimes in solids also).
(B) By mode of operation
CW
Pulsed
(C) By pumping and laser levels
3-level laser
4-level laser
This belongs to Physical Chemistry portion and it contains most of
things about laser working and principles.
By Aaryan Tyagi's Group
M.Sc. Applied Chemistry (1 Sem)
Amity University, Noida
Laser characteristics as applied to medicine and biologykaroline Enoch
Laser” is an acronym for light amplification by stimulated emission of radiation. A laser is created when the electrons in atoms in special glasses, crystals, or gases absorb energy from an electrical current or another laser and become “excited.”Characteristics ,working ,types and application of lasers exclusively in medicine and biology.
Laser Surgery Facial Mole:By Dr.K.O.Paulose FRCS DLODr. Paulose
Laser Excision of Moles in Face, Head and Neck:By Dr.K.O.Paulose.FRCS DLO, Consultant ENT Surgeon, Jubilee Hospital. Trivandrum.South India.
www.drpaulose.com
www.snorefreesleep.com
Lasers in medicine, basic principles and applicationAugustine raj
Lasers are being used frequently in medical practice. every physician should know the mechanism of action and indications and different types of lasers used in medical practice. i have tried to simplify the entire presentation.
Laser, Pumping schemes, types of lasers and applicationsPraveen Vaidya
The document gives good insite into the different pumping schemes, different types of lasers and Applications like Holographys, laser cutting and Laser Beam Welding.
Magnets are available every where. Very little people understands the healing properties of magnets. Dr. Desh Bandhu Bajpai is a medical practitioner and is using magnets for healing purposes. In this slide show , you will find the properties of magnets and other details.
Before you used to spend money on oral medications to get health.
Now spend once for life time medication to have health and get life time income even after your death.
For details. watch
http://tinyurl.com/biokamran
If you have health, you probably will be happy, and if you have health and happiness, you have all the wealth you need, even if it is not all you want.
~Elbert Hubbard~
A laser is a device that generates light by a process called STIMULATED EMISSION.
The acronym LASER stands for Light Amplification by Stimulated Emission of Radiation
Semiconducting lasers are multilayer semiconductor devices that generates a coherent beam of monochromatic light by laser action. A coherent beam resulted which all of the photons are in phase.
Contents
Definition of a laser
Emission and absorption of radiation
Population Inversion
Optical Feedback
Fundamentals of laser operation
Laser Hazards
INTRODUCTION
HISTORY
PRINCIPLES OF WORKING OF A LASER
FUNDAMENTALS OF LASER
CHARACTERISTICS OF LASER
CLASSIFICATION OF LASER
EFFECTS OF LASER ON SOFT AND HARD TISSUES
VARIOUS LASERS AVAILABLE FOR PERIDONTAL USE
APPLICATION OF LASER TREATMENT IN PERIODONTAL THERAPY
ADVANTAGES & DISADVANTAGES OF LASER IN PERIODONTAL THERAPY
LASER PRECAUTIONS
LASER HAZARDS
RECENT ADVANCES
CONCLUSION
Characteristic of light
History
Laser physics and properties
Component of laser
Classification of laser
Biological effect of laser
Laser effect on dental tissues
Laser safety in dental practice
General application of laser
Personal protective equipment
Types of laser intensity in orthodontics
Uses of laser in orthodontics
Effect of laser in orthodontics
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
1. LASER APPLICATIONS TO
MEDICINE AND
Prof. Dr. Moustafa. M. Mohamed
Vice Dean
Faculty of Allied Medical Science
Pharos University
Alexandria
Dr. Mervat Mostafa
Department of Medical Biophysics
Pharos University
2. FIRST OFF WHAT DOES
LASER STAND FOR?
LLIGHTIGHT
AAMPLIFICATION BYMPLIFICATION BY
SSTIMULATEDTIMULATED
EEMISSION OFMISSION OF
RRADIATIONADIATION
3. Basic Concepts:
Laser is a narrow beam of light of a single
wavelength (monochromatic) in which each
wave is in phase (coherent) with other near
it.
Laser apparatus is a device that produce an
intense concentrated, and highly parallel
beam of coherent light.
4. Basic theory for laser
(Einstein 1917(:
Atom composed of a nucleus and electron cloud
If an incident photon is energetic enough, it may
be absorbed by an atom, raising the latter to an
excited state.
It was pointed out by Einstein in 1917 that an
excited atom can be revert to a lowest state via
two distinctive mechanisms:
Spontaneous Emission and
Stimulated Emission.
5. Spontaneous emission:
Each electron can drop back
spontaneously to the ground state emitting
photons.
Emitted photons bear no incoherent. It
varies in phase from point to point and
from moment to moment.
e.g. emission from tungsten lamp.
6. Stimulated emission:
Each electron is triggered into emission by the
presence of electromagnetic radiation of the
proper frequency. This is known as stimulated
emission and it is a key to the operation of laser.
e.g. emission from Laser
Excited state
Ground state
hν
7. Absorption:
Let us consider an atom that is initially in
level 1 and interacts with an
electromagnetic wave of frequency n. The
atom may now undergo a transition to level
2, absorbing the required energy from the
incident radiation. This is well-known
phenomenon of absorption.
E
E2
hν=E2 – E1
8. According to Boltzmann's statistics, if a
sample has a large number of atoms, No, at
temperature T, then in thermal equilibrium
the number of atoms in energy states E1 and
E2 are:
N1 = No e-E
1
/kT
N2 = No e-E
2
/kT
If E1 < E2 Then N1 > N2
If E1 < E2 and N1 < N2 This is called
"Population Inversion".
9. Population inversion:
Generally electrons tends to (ground state).
What would happen if a substantial
percentage of atoms could somehow be
excited into an upper state leaving the lower
state all empty? This is known as a
population inversion. An incident of photon
of proper frequency could then trigger an
avalanche of stimulated photon- all in phase
(Laser).
10. Consider a gas enclosed in a vessel
containing free atoms having a number of
energy levels, at least one of which is
Metastable.
By shining white light into this gas many
atoms can be raised, through resonance,
from the ground state to excited states.
11. Population Inversion
E1 = Ground state,
E2 = Excited state (short life time ns),
E3 = Metastable state (long life time from
ms to s).
hν =5500 Αο
E1
E2
E3
10-3
-1 sec
10-9
sec
Output
(amplification)
Life times
Excitation
12. To generate laser beam three processes
must be satisfied:-
Population inversion.
Stimulated emission.
Pumping source.
MEDIUM
PUMP
MIRROR
COLLIMATED
BEAM
13. Pumping Sources
Optical Pumping: Suitable For Liquid And Solid
Laser Because They Have Wide Absorption
Bands.
Electric Pumping: Suitable For Gas Laser Because
They Have Narrow Absorption Band.
Chemical Reaction.
14. Types of lasers
According to the active material:
solid-state, liquid, gas, excimer or semiconductor
lasers.
According to the wavelength:
Infra-red (IR), Visible, Ultra-violet (UV) or X-ray
Lasers.
15. Solid-state lasers have lasing material
distributed in a solid matrix (such as ruby or Nd-
YAG). Flash lamps are the most common power
source. The Nd-YAG laser emits infrared light at
1.064 nm.
Semiconductor lasers, sometimes called diode
lasers, are p-n junctions. Current is the pump
source. Applications: laser printers or CD players.
Types of lasers
16. Dye lasers use complex organic dyes, such as
Rhodamine 6G, in liquid solution or suspension as
lasing media. They are tunable over a broad range
of wavelengths.
• Gas lasers are pumped by current. Helium-
Neon (He-Ne) lasers in the visible and IR. Argon
lasers in the visible and UV. CO2 lasers emit light
in the far-infrared (10.6 mm), and are used for
cutting hard materials.
Types of lasers
17. Excimer lasers: (from the terms excited
and dimers) use reactive gases, such as
chlorine and fluorine, mixed with inert
gases such as argon, krypton, or xenon.
When electrically stimulated, a pseudo
molecule (dimer) is produced. Excimers
laser in the UV.
18. Solid-state Laser
Example: Ruby Laser
Operation wavelength: 694.3 nm (IR)
3 level system: absorbs green/blue
Gain Medium: crystal of aluminum oxide (Al2O3)
with small part of atoms of aluminum is replaced
with Cr3+
ions.
Pump source: flash lamp
The ends of ruby rod serve as laser mirrors.
20. How Ruby laser works?
1. High-voltage electricity causes the quartz
flash tube to emit an intense burst of light,
exciting some of Cr3+ in the ruby crystal to
higher energy levels.
21. 2. At a specific energy level, some Cr3+
emit
photons. At first the photons are emitted in all
directions. Photons from one Cr3+
stimulate
emission of photons from other Cr3+
and the light
intensity is rapidly amplified.
How Ruby laser works?
22. 3. Mirrors at each end reflect the photons back and
forth, continuing this process of stimulated
emission and amplification
How Ruby laser works?
23. 4. The photons leave through the partially silvered
mirror at one end. This is laser light.
How Ruby laser works?
24. High and Low Level Lasers
High Level Lasers
–Surgical Lasers
–Hard Lasers
–Thermal
–Energy (3000-10000) mW
25. Low Level Lasers
–Medical Lasers
–Soft Lasers
–Subthermal
–Energy (1-500) mW
–Therapeutic (Cold) lasers produce maximum
output of 90 mW or less (600-1000) nm light
27. Wavelength
Nanometers (nm)
Longer wavelength (lower frequency) = greater
penetration
Not fully determined
Wavelength is affected by power
28. Power
Output Power
–Watts or milliwatts (W or mW)
–Important in categorizing laser for safety
Intensity
Power Density (intensity)
–W or mW/ cm2
– Takes into consideration – actual beam diameter
If light spread over lager area – lower power
density
– Beam diameter determines power density
29. Average Power
Knowing average power is important in
determining dosage with pulsed laser
If laser is continuous – average power = peak
output power
If laser is pulsed, then average power is equal to
peak output power X duty cycle.
30. Energy Density
Dosage (D)
Amount of energy applied per unit area
Measured in Joules/square cm (J/cm2
)
– Joule – unit of energy
– 1 Joule = 1 W/sec
Dosage is dependent on:
–Output of laser in mW.
– Time of exposure in seconds.
– Beam surface area of laser in cm2
31. Laser Treatment &
Diagnostics
Treatment cover everything from the ablation of
tissue using high power lasers to photochemical
reaction obtained with a weak laser.
Diagnostics cover the recording of fluorescence
after excitation at a suitable wavelength and
measuring optical parameters.
33. What Does Laser Do?
Laser light waves penetrate the skin with no
heating effect, no damage to skin & no sideeffects.
Laser light directs biostimulative light energy to
the body’s cells which convert into chemical
energy to promote natural healing & pain relief.
Stimulation of wound healing
– Promotes faster wound healing/clotformation
–Helps generate new & healthy cells & tissue
34. Increase collagen production
–Develops collagen & muscle tissue
Increase macrophage activity
– Stimulates immune system
Alter nerve conduction velocity
– Stimulates nerve function
What Does Laser Do?
35. Improved blood circulation & vasodilation
– Increases blood supply
• Increases ATP production
• Analgesic effect
– Relieves acute/chronic pain
• Anti-inflammatory & anti-edematous effects
– Reduces inflammation
What Does Laser Do?
36. Tissue & Cellular
Response
Magnitude of tissue’s reaction are based on
physical characteristics of:
–Output wavelength/frequency
–Density of power
–Duration of treatment
– Vascularity of target tissues
37. Direct and indirect laser effects
Direct effect - occurs from
absorption of photons
Indirect effect – produced by
chemical events caused by
interaction of photons emitted from
laser and the tissues
38. LASER Regulation
Lasers are classified according to the hazard;
* Class 1 and 1M (magnifier) lasers are
considered safe
* Class 2 and 2M (magnifier)
- emit visible light at higher levels than Class 1,
- eye protection is provided
- can be hazardous if the beam is viewed directly
with optical instruments;
39. * Class 3R (Restricted) Laser
- produce visible and invisible light that are
hazardous under direct viewing conditions;
* Class 3B lasers
- produce visible or invisible light that is hazardous
under direct viewing conditions
- they are powerful enough to cause eye damage in a
time shorter
- Laser products with power output near the upper
range of Class 3B may also cause skin burns;
40. * Class 4 lasers
- high power devices capable of causing both eye
and skin burns,
- heir diffuse reflections may also be hazardous
- the beam may constitute a fire hazard;