Biomedical Instrumentation- X-RAY Machine

Summary

This lecture introduces the basic components of an X-ray machine and their functions. Key elements discussed include the power supply arrangement, where step-up and step-down transformers regulate voltage for the anode and cathode; the aluminum filter, which blocks low-energy X-rays to improve image quality; the collimator, used to shape the X-ray beam; and the X-ray imaging device, where the beam interacts with a fluorescent screen to produce an image. The lecture emphasizes how each component contributes to the overall process of X-ray imaging and patient safety.

Takeaways

• 😀 Power supply arrangement is crucial for operating the X-ray machine, involving both low AC and high DC voltage.
• 😀 The X-ray tube consists of an anode and cathode, each supplied with different voltage types (AC for cathode, DC for anode).
• 😀 A step-down transformer is used to supply low AC voltage to the cathode.
• 😀 A step-up transformer increases the AC voltage before it is rectified and supplied to the anode.
• 😀 Aluminum filters are used to block low-energy X-rays, which can decrease image contrast and are absorbed by patient tissues.
• 😀 Low-energy X-rays are ineffective for imaging and can harm image quality by reducing contrast.
• 😀 The collimator, also known as a beam-limiting device, shapes the X-ray beam before it reaches the patient.
• 😀 Collimators are placed between the X-ray tube and the patient to control the direction and size of the X-ray beam.
• 😀 The X-ray imaging device includes a fluorescent screen that captures the X-ray beam after it passes through the body part being examined.
• 😀 The fluorescent screen emits visible light when exposed to X-rays, allowing the image to be seen.

Q & A

What are the basic components of an X-ray machine?

The basic components of an X-ray machine include the power supply arrangement, X-ray tube, aluminum filter, collimator, and X-ray imaging device.

How does the power supply arrangement work in an X-ray machine?

The power supply arrangement involves two transformers: a step-down transformer to supply low AC voltage to the cathode, and a step-up transformer to increase AC voltage, which is then rectified to provide high DC voltage to the anode.

What is the role of the X-ray tube in the X-ray machine?

The X-ray tube consists of an anode and a cathode. The cathode receives low AC voltage and the anode receives high DC voltage. This arrangement is essential for generating X-rays within the tube.

Why is an aluminum filter used in an X-ray machine?

An aluminum filter is used to block low-energy X-rays that would decrease image contrast and be heavily absorbed by the patient's soft tissue, reducing the overall image quality.

What is the purpose of the collimator in an X-ray machine?

The collimator is a beam-limiting device placed between the X-ray tube and the patient. It shapes the X-ray beam to focus it on the area of the body being examined.

What are low-energy X-rays and why are they removed from the X-ray beam?

Low-energy X-rays are less effective at creating clear images and can be absorbed by the patient's soft tissue. Removing them improves image contrast and reduces unnecessary radiation exposure.

How does the X-ray imaging device create an image?

After the X-ray beam passes through the patient, it strikes a fluorescent screen. The material in the screen emits visible light when hit by the X-rays, which then creates the visible image for diagnosis.

What happens if the X-ray beam is not properly collimated?

If the X-ray beam is not properly collimated, it may irradiate unnecessary areas of the patient’s body, leading to increased radiation exposure and reduced image clarity.

Why is it important to have high DC voltage at the anode in the X-ray tube?

High DC voltage at the anode is necessary to accelerate the electrons that generate X-rays when they collide with the anode, which is a key process in X-ray production.

How does the X-ray machine minimize radiation exposure to the patient?

The X-ray machine minimizes radiation exposure through the use of aluminum filters to block low-energy X-rays, collimation to limit the area exposed, and by generating only the necessary amount of X-rays for imaging.