X-ray Generators PDF

X-ray Generators X-ray generators provide electrical power/high voltage dc supply to x-ray tubes. The tube requires electrical energy for 2 purposes: 1. To boil electrons from filament 2. To accelerate el...

X-ray Generators X-ray generators provide electrical power/high voltage dc supply to x-ray tubes. The tube requires electrical energy for 2 purposes: 1. To boil electrons from filament 2. To accelerate electrons from cathode to anode Transformer: is a device that increases the voltage in a circuit in an x-ray generator. They are used to change the potential difference of incoming electric energy to appropriate level. o Transformers only work on Alternating current (AC) therefore a rectifier (rectification) is used. o Alternating current is converted to a direct current (DC) using diodes (solid state devices or semiconductors). § Rectification: conversion of an alternating current (AC) to a direct current (DC) § Rectifier: a device that allows an electrical current to flow in one direction but does not a;;pw current to flow in the other direction. e.g diode Three phase power supply: consists of three lines of voltage, each 120 degrees out of phase with the others (0°, 120°, 240° phase). 3 types of X-ray generators most commonly used: (1) Single-phase power supply (2) Three-phase power supply (3) High Frequency Generators High Frequency Generator The high-frequency part refers to the electrical power source that drives the X-ray tube. High-frequency X-ray generators, operate at much higher frequencies than traditional x-ray machines. The benefits of high-frequency X-ray generators are that they can provide more precise control over the X-ray output, reduce patient dose, and allow for faster imaging. Advantage of High Frequency Generator (HFG) compared to Single-phase or Three-phase generator Single or Three phase power supply can be used Transformers are more efficient at higher frequencies The overall size is smaller. The transformer tank is about one-tenth the size of the Three-Phase Generator and it produces x-rays more efficiently at high frequencies. This reduces the overall cost of the system. 1 Automatic Exposure Control (AEC) or phototimer: Automatic Exposure Control (AEC) minimizes radiation exposure to patients by automatically terminating exposure when a present amount of radiation has been detected. Automatically control exposure factors during an X-ray examination. Provides consistent optical density/ signal-to-noise ratio between images Ionisation chambers (positioned between patient and image receptor) measure exposure by detecting liberated electron charge when x-ray photons ionise the gas within the chamber. Benefits of AEC: Automatic Exposure Control offers several advantages: Improved image consistency. Minimization of the risk of overexposure or underexposure. Reduction of radiation dose to patients. Enhanced workflow efficiency for radiologic technologists. 2