40 Questions
What is the process by which an electron changes energy levels and emits a photon in a random direction?
Spontaneous emission
What is the primary function of the optical resonator in a laser system?
To reflect the laser beam back and forth through the active medium
What is the term for the property of laser light where all waves are in phase, both in time and space?
Coherence
Which type of laser is commonly used in laser surgery?
Ruby laser
What is the term for the interaction between laser light and biological tissues?
Laser tissue interaction
What is the primary advantage of using lasers in medicine?
Increased precision and accuracy
What is the term for the measure of the amount of energy emitted by a laser per unit time?
Power
Which of the following is a safety concern in medical applications of lasers?
All of the above
What is the term for the classification of lasers based on their wavelength?
Infrared, visible, ultraviolet, or X-ray
What is the term for the type of laser that emits a continuous beam of light?
Continuous wave laser
What is the primary mechanism of high power lasers in medical applications?
Generating heat and destroying targeted tissue
What is the typical effect of mid-power lasers, such as helium-neon laser, on tissue?
Superficial effect with penetration up to 1.5 mm
What is the unit of measurement for power density of laser light?
Milliwatts per centimeter squared
What is the primary mechanism of low-power lasers, such as soft laser, in medical applications?
Biostimulation and tissue healing
What is the term for the amount of power per unit area of laser light?
Power density
What is the primary mechanism of laser tissue interaction that results in no biological effect?
Reflection
What is the typical wavelength of an argon laser?
488-514 nm
What is the unit of measurement for the total energy of a laser pulse used in medicine?
Milli joules
What is the primary application of mid-power lasers, such as I.R. laser, in medicine?
Physical therapy
What is the term for the rate of energy flow of laser light?
Power
What is the main difference in energy deposition between xenon arc treatment and laser treatment?
Xenon arc treatment deposits 20 to 50 times more energy than laser treatment
What is the purpose of using local anesthesia during xenon arc treatment?
To reduce eye movement
What determines the amount of laser energy needed for photocoagulation?
The spot size used
What is the purpose of photocoagulation in ophthalmology?
To repair retinal tears or holes
What is the Minimal Reactive Dose (MRD) of laser energy?
The minimum amount of energy that causes damage to the retina
What is the typical exposure needed for photocoagulation?
10 to 50 times the MRD
What is a medical application of lasers in dermatology?
Removing tattoos
What is the advantage of using lasers in surgery?
It reduces bleeding
How are lasers used in gastroscopy?
Through a combination with fiber optics
What is a medical application of lasers in ophthalmology?
Treating diabetic retinopathy
What is the primary purpose of laser energy in medicine?
To deliver energy to tissue
What is the effect of laser energy on human tissue?
It causes a rapid rise in temperature
Why are short wave lasers (400-600nm) preferred over long wave lasers (700nm) in medical applications?
Short wave lasers are better absorbed by tissue
What is the minimum temperature required to cause tissue destruction?
100°C
What is the primary application of lasers in ophthalmology?
Photocoagulation of the retina
What was the primary disadvantage of xenon arc light source for photocoagulation?
The retinal spot size was much larger
What is the duration of exposure to 70°C that tissue can withstand?
1 second
What is the impact of laser energy on biological tissue?
It causes both biological and chemical reactions
What is the primary advantage of laser technology in medicine?
It is more precise and controlled
What is the medical application of laser technology in treating cancer?
It is used to treat certain types of cancer
Study Notes
What is a Laser?
- Light Amplification by Stimulated Emission of Radiation (LASER)
- An electron transition from higher to lower energy state emits a photon
- Emission process can be spontaneous or stimulated emission
Basic Components of a Laser
- Active medium or laser medium
- Energy source (pump or pump source)
- Optical resonator consisting of a mirror or system of mirrors
Laser Properties
- Coherence: all waves are in phase, both in time and in space
- Monochromaticity: one wavelength and one color
- Collimation: waves travel in parallel directions (non-divergent)
- Brightness: high energy density
Types of Lasers
- According to active material: solid-state, liquid, gas, excimer, or semiconductor lasers
- According to wavelength: Infra-red (IR), Visible, Ultra-violet (UV), or X-ray Lasers
- Pulse Laser: Ruby laser (λ=694 nm), Semiconductor laser, Glass laser
- Continuous Wave (CW) Laser: Neon-helium laser (λ=632.8 nm), Argon laser (λ=488-514nm)
Classification of Lasers
- High Power Lasers (Hot): e.g., Co₂ laser
- Mid-Power Lasers (Cold): e.g., I.R. laser, Helium neon (He Ne) laser, Infrared (IR) laser
- Low-Power Lasers (Soft Laser): e.g., used by dermatologists
Laser Power
- Measured in watts (W) or milliwatts (mW)
- Power density: measured in milliwatts per centimeter squared (mW/cm²)
Laser-Tissue Interaction
- Reflection: beam is reflected from the tissue without affecting it
- Scattering: laser light is scattered, attenuating the desired energy
- Transmission: laser beam penetrates through the tissue without affecting it
- Absorption: laser energy is absorbed by the tissue, causing biological and chemical reactions
Medical Applications of Lasers
- Ophthalmology: photocoagulation of the retina, treating certain types of cancer
- Dermatology: skin tumor therapy, tattoos removal
- Surgery: used for precise cutting and sealing of blood vessels, reducing bleeding
Laser in Ophthalmology
- Photocoagulation: heating blood vessels to coagulate and block them
- Xenon arc light source: disadvantages include larger retinal spot size, greater energy deposition, and longer exposures
- Minimum Reactive Dose (MRD): the minimum laser energy that causes observable damage to the retina
This quiz covers the basics of laser technology in medicine, including its properties, applications, and interactions with tissues. It's a part of Medical Physics course.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
