Respiratory Volumes and Capacities

Respiratory Volumes

• Tidal Volume is the volume of air inspired or expired during normal respiration
• Inspiratory Reserve Volume is the additional volume of air a person can inspire by a forcible inspiration
• Expiratory Reserve Volume is the additional volume of air a person can expire by a forcible expiration

Respiratory Capacities

• Functional Residual Capacity is the volume of air that remains in the lung after normal expiration
• Inspiratory Capacity is the total volume of air a person can inspire after a normal expiration
• Expiratory Capacity is the total volume of air a person can expire after a normal inspiration
• Vital Capacity is the maximum volume of air one can breathe in after a forced expiration
• Total Lung Capacity is the total volume of air accommodated in the lung after the end of a forced inspiration

Gamma Camera and Electronic Systems

• The electronic systems detect light energy from the detector and convert it into electrical signals.

Pressure and Height

• Pressure difference (ΔP) can be used to calculate the height of a building, given the density of air (ρ) and the acceleration due to gravity (g).
• Formula: ΔP = Pbottom - Ptop = ρgh, where h is the height of the building.

Gage Pressure in a Liquid

• The gage pressure in a liquid at a certain depth can be expressed as P = ρgh, where ρ is the density of the liquid, g is the acceleration due to gravity, and h is the height of the liquid.
• The gage pressure at two different depths of a liquid can be related by the formula: P2 = P1 × h2/h1.

Specific Heat of Mercury

• The specific heat of mercury can be calculated by measuring the temperature change (ΔT) when a sample of mercury absorbs a certain amount of energy (Q).
• Formula: specific heat = Q / (m × ΔT), where m is the mass of the mercury sample.

Radioactive Atom and Radiopharmaceutical

• An unstable atom is said to be radioactive, emitting excess energy or mass to reach stability.
• Radiation emissions can be in the form of alpha (α), beta (β), or gamma (γ) particles.
• A radiopharmaceutical is a radioactive drug used for diagnosis or therapy, consisting of a radionuclide and a carrier molecule.

Nuclear Medicine Imaging

• Nuclear medicine imaging uses small amounts of radioactive pharmaceuticals to image the body and diagnose disease.
• It helps doctors "view" how the body is functioning, rather than just its structure.

Gamma Camera

• A gamma camera is a device used to obtain an image of the distribution of a radiopharmaceutical in the body.
• It consists of three main parts: a collimator, a detector, and electronic systems.

The Collimator

• The collimator is usually made of lead and contains thousands of tiny holes.
• Only gamma rays that travel through the holes in the collimator will be detected.

The Detector

• The detector is a scintillation crystal, typically made of Sodium Iodide with traces of Thallium added.
• It converts gamma rays into light energy through mechanisms such as photoelectric effect, Compton scatter, and pair production.

Scintillation Detector

• The scintillation detector produces "fast electrons" with high kinetic energy when gamma rays interact with the crystal.
• The detector is usually paired with a photomultiplier tube to amplify the light signal.