Medical Equipment: LINAC, CPB Circuit, and Hemodialysis
Radiotherapy: Linear Accelerator (LINAC) for External Photon Radiation Therapy
A Linear Accelerator (LINAC) is used for external photon radiation therapy. Here’s a breakdown of its key components:
- Magnetron (Klystron): Accelerates electrons created in the electron gun by generating electromagnetic waves. These waves are directed towards the waveguide system.
- Waveguide System (Accelerator Tube): A long, tubular structure where electrons are accelerated. It receives electrons from the electron gun and microwaves from the magnetron. A vacuum is created within, and the system is cooled with water.
- Electron Gun: Contains a tungsten filament. It produces electrons that will be accelerated. The quantity of electrons depends on the gun’s temperature.
- X-Ray Beam (Radiation): The desired output for treatment.
- Steering Coils: Used to center the electron beam within the waveguide.
- Focusing Coils: Reduce the diameter of the electron beam within the waveguide.
- Bending Magnet: Redirects the accelerated electrons from a horizontal to a vertical path. It focuses the electron beam to a final diameter of 1mm. At the exit of this magnet, the electron beam hits the target to generate X-rays.
- X-Ray Target (Tungsten): Part of the treatment head, made of tungsten. Electrons strike this target, causing it to emit photons (X-rays).
- Primary Collimator/Flattering Filter: Generates a constrained and uniform X-ray beam.
- Ion Chambers (Beam Monitor Device): Measure the dose and the distribution of the dose within the beam.
- Secondary Collimator (Multi-leaf Collimator): Consists of two pairs of lead jaws that open and close to create the desired beam shape for the patient.
Heart-Lung Machine: Cardiopulmonary Bypass (CPB) Circuit
A Cardiopulmonary Bypass (CPB) circuit, also known as a heart-lung machine, temporarily takes over the functions of the heart and lungs during surgery. Here are its main components:
- Cannulae: Connect the heart to the CPB machine.
- Venous Cannula: Can be single-stage or dual-stage.
- Arterial Cannula
- Cardioplegia Cannula
- Reservoir: Collects and stores blood from the three circuits. It is positioned low to facilitate gravity drainage and has a large volume capacity.
- Cardiotomy Reservoir: Separates air from blood in the suction circuit.
- Pumps:
- Roller Pumps: Maintain consistent blood flow.
- Centrifugal Pumps: Provide smoother blood flow and reduce damage to blood cells.
- Oxygenator: Oxygenates the blood before it is returned to the body. It uses semipermeable tubes.
- Heat Exchangers: Adjust the temperature of the blood before it is returned to the body. Cooling slows down metabolism and increases blood’s oxygen-carrying capacity.
- Filters and Air Detector: Eliminate the potential for embolisms (air bubbles).
- Other Components: Temperature, oxygen saturation, pressure, and flow sensors, as well as gas blenders.
Dialysis: Hemodialysis
Hemodialysis is a treatment that filters waste and excess fluid from the blood when the kidneys are not functioning properly. Here’s a breakdown of the process:
- Vascular Access:
- Fistula
- Graft
- Central Venous Catheter
- Blood Pump: A roller-type pressure pump that pushes blood to the dialyzer.
- Heparin Pump: Delivers an anticoagulant (heparin) at a specific rate to prevent blood clotting. It is typically a syringe-type pump.
- Dialyzer: A container with special filters (semi-permeable membranes) that remove waste, impurities, and excess water from the blood.
- Dialysate Circuit: Includes a heating device and a detector.
- Arterial and Venous Blood Pressure Detectors: Monitor blood pressure. Arterial pressure is negative, while venous pressure is positive.
- Air/Bubble Detector: Automatically stops the blood pump if air is detected.
- Cleaning Elements: Saline solution is used for cleaning.