Understanding Thermography Measurements for Body Temperature

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Questions and Answers

What is heat?

Heat is the energy transferred to the molecules causing the temperature rise.

What is absolute zero?

Absolute zero is the temperature of -273.5°C, which is experimentally unattainable.

What is the relationship between kinetic energy and temperature?

The kinetic energy of molecules is related to temperature.

What is the Fahrenheit scale?

The Fahrenheit scale is a temperature scale where water freezes at 32°F and boils at 212°F. Signup and view all the answers

What is the Celsius scale?

The Celsius scale, also known as the centigrade scale, is the most common temperature scale. Signup and view all the answers

How can the temperature of a gas be increased?

The temperature of a gas can be increased by increasing the average kinetic energy of its molecules. Signup and view all the answers

What is cryobiology?

The study of low temperature effects in biology and medicine. Signup and view all the answers

What is cryopreservation?

The long-term preservation of blood, sperm, bone marrow, and tissues using low temperatures. Signup and view all the answers

How does ultrasonic heating relieve tightness and scarring in joint disease?

By vibrating tissues and producing heating. Signup and view all the answers

Why is the preservation of blood at the temperature of liquid nitrogen much better than at the temperature of solid carbon dioxide?

Because cells survive better at the temperature of liquid nitrogen. Signup and view all the answers

What is cryosurgery used for?

Destroying cells in the treatment of Parkinson's disease, tumors, warts, and in eye surgery. Signup and view all the answers

Why are skin, bone, muscle, and organs harder to preserve than blood?

Due to their large physical dimensions and the difficulty in adding and removing protective agents. Signup and view all the answers

What is the purpose of cryosurgical probe temperature control in cryosurgery?

To control the volume of destroyed tissue. Signup and view all the answers

Why is the survival of some cells after freezing more dependent upon the cooling rate than the warming rate?

Because the cooling rate during freezing affects cells' survival more than the warming rate during thawing. Signup and view all the answers

What are the advantages of cryosurgery?

Little bleeding, controlled tissue volume destruction, and minimal pain sensation. Signup and view all the answers

Why is ultrasonic heating useful for deposition heat in bones?

Because bones absorb ultrasound energy more effectively than soft tissue. Signup and view all the answers

What is the boiling point of water in Celsius?

100 °C Signup and view all the answers

What is the boiling point of water in Kelvin?

373.15 K Signup and view all the answers

What is the change in temperature from 30 °C to the boiling point of water in Kelvin?

70 K Signup and view all the answers

What is the formula to convert temperature from Celsius to Kelvin?

T(K) = T(°C) + 273.15 Signup and view all the answers

What is the formula to convert temperature from Celsius to Fahrenheit?

T(°F) = 1.8T(°C) + 32 Signup and view all the answers

What type of thermometer uses the expansion of mercury or alcohol to measure temperature?

Glass fever thermometer Signup and view all the answers

What is the principle behind the glass fever thermometer?

Different materials expand differently with temperature Signup and view all the answers

What is the main physical property measured by a thermistor to determine temperature?

Electrical resistance Signup and view all the answers

What is the temperature range that a thermocouple can measure?

-190 to 300 °C Signup and view all the answers

What type of thermometer measures temperature by sensing infrared energy?

Infrared thermometer Signup and view all the answers

What does an infrared thermometer use to convert radiant energy into an electric signal?

Detector Signup and view all the answers

What is the significance of the absolute zero on the Kelvin scale?

0 K is equal to -273.15 °C Signup and view all the answers

What is the dominant factor affecting body surface temperature in thermography?

Blood flow near the skin Signup and view all the answers

What is the most common use of thermography in medical diagnosis?

To detect breast cancer Signup and view all the answers

What equation describes the radiation emitted by a body in the infrared region?

W = eσT^4 Signup and view all the answers

What is the power radiated per cm^2 from skin at a temperature of 33°C?

0.05W cm^2 Signup and view all the answers

What are the two primary therapeutic effects of heat in a heated area?

Increase in metabolism resulting in vasodilation and increase in blood flow Signup and view all the answers

What are the physical methods of producing heat in the body?

Conductive heating, infrared radiant heating, radio wave heating, microwave diathermy, ultrasonic wave heating Signup and view all the answers

What is the wavelength range of the infrared (IR) radiant heating used for surface heating of the body?

800-4000 nm Signup and view all the answers

What condition is conductive heating used in treating?

Arthritis, neuritis, sprains, strains, contusions, sinusitis, back pain Signup and view all the answers

What is the wavelength range of the waves used in microwave diathermy?

Radar range (wavelength = 12cm) Signup and view all the answers

What is the primary use of microwave diathermy in therapy?

Treatment of fractures, sprains and strains, bursitis, injuries to tendons Signup and view all the answers

What are the two different methods used for transferring the electromagnetic energy in the body in radio wave heating (Diathermy)?

Electrodes energized by high-frequency voltage, magnetic induction Signup and view all the answers

What is the frequency of the waves used in ultrasonic wave heating (ultrasonic diathermy)?

~1MHz Signup and view all the answers

Study Notes

Understanding Heat and Temperature

Heat is the form of energy transferred between systems or objects with different temperatures, always moving from warmer to cooler areas.
Absolute zero is the theoretical minimum temperature, measured as 0 Kelvin (-273.15°C), where molecular motion ceases.
Kinetic energy is directly proportional to temperature; as the temperature increases, so does the kinetic energy of particles.

Temperature Scales

The Fahrenheit scale sets the freezing point of water at 32°F and the boiling point at 212°F.
The Celsius scale has a freezing point of water at 0°C and a boiling point at 100°C.
Temperature conversion from Celsius to Kelvin uses the formula: K = °C + 273.15.
For Celsius to Fahrenheit, the formula is: °F = (°C × 9/5) + 32.

Gas Temperature Changes

The temperature of a gas can be increased by adding heat or reducing pressure, leading to an increase in kinetic energy of gas molecules.

Cryobiology is the study of how living organisms respond to low temperatures.
Cryopreservation is the process of preserving cells, tissues, or organs by cooling them to sub-zero temperatures.
Ultrasonic heating can alleviate tightness and scarring in joint disease by increasing blood flow and tissue elasticity.

Blood Preservation and Cryosurgery

Blood preservation at liquid nitrogen temperatures (-196°C) is superior to solid carbon dioxide (-78°C) due to better maintenance of cellular integrity during freezing.
Cryosurgery uses extreme cold to destroy abnormal or diseased tissue, commonly used in dermatology and oncology.

Preservation Challenges

Skin, bone, muscle, and organs are more challenging to preserve compared to blood due to their complex structures and higher water content, leading to ice crystal formation during freezing.
Temperature control in cryosurgical probes is vital to ensure precise application of cold and minimize damage to surrounding tissues.

Cell Survival and Freezing Rates

The survival rate of some cells after freezing is more sensitive to cooling rates because rapid cooling can minimize ice crystal formation, while warming depends more on metabolic recovery processes.

Advantages of Cryosurgery

Benefits include minimal invasiveness, reduced risk of infection, and the ability to target specific tissue without affecting surrounding areas.

Thermometry and Measurement

Glass fever thermometers measure temperature through the expansion of mercury or alcohol.
Thermistors determine temperature based on resistance changes, while thermocouples can measure a wide range of temperatures.
Infrared thermometers detect temperature by sensing emitted infrared energy, converting it into an electrical signal.

Medical Thermography

Thermography helps assess body surface temperatures, with medical diagnosis frequently utilizing it to detect inflammation or abnormal tissue.
The equation describing infrared radiation emitted by a body plays a role in evaluating temperature distribution on the skin.

Heat Therapy

Two primary therapeutic effects of heat include pain relief and improved range of motion in treated areas.
Conductive heating is commonly used in treating conditions such as muscle spasms, while microwave diathermy is primarily utilized for deep tissue heating.
Electromagnetic energy transfer methods in radio wave heating (Diathermy) include capacitive and resistive methods.
Ultrasonic diathermy operates using frequency waves typically between 1-3 MHz for therapeutic effects.

Infrared and Microwave Applications

Infrared radiant heating typically operates in the wavelength range of 700 nm to 1 mm for effective surface heating.
Microwave diathermy uses wave lengths around 1 mm to 10 cm for therapeutic applications, focusing on deeper muscle and tissue layers.

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Description

Explore the concept of thermography measurements for body surface temperature, the factors affecting it, and its relation to pathologic conditions. Figure 6 illustrates a thermogram of a hand. Gain insights into how researchers have attempted to accurately measure body surface temperature.