Week 1: Session 2 – Basics of Radiation and Image Production

Text Explanation for Session 2:

1. X-ray Production:

   • X-rays are produced in the X-ray tube, which is a critical part of the X-ray machine. Inside the tube, electrons are accelerated from the cathode (negatively charged) to the anode (positively charged). When these high-energy electrons hit the anode (usually made of tungsten), they slow down rapidly, resulting in the production of X-rays. There are two primary types of radiation produced in this process: Bremsstrahlung radiation (braking radiation) and characteristic radiation. The X-rays produced are then directed toward the patient, where they pass through the body and interact with tissues, forming an image on the detector.

2. Properties of X-rays:

   • X-rays have several unique properties that make them useful for medical imaging. They can penetrate various materials, including human tissues, to varying degrees. Bones, for example, absorb more X-rays than soft tissues, which is why they appear white on radiographs. This property of differential absorption, or attenuation, is what allows us to visualize internal structures. However, X-rays can also cause ionization, which means they have the potential to damage biological tissues, underscoring the importance of radiation protection.

3. Radiographic Image Formation:

   • The X-ray image is formed based on how different tissues absorb or transmit X-rays. The primary factors affecting the quality of the radiographic image are density (the overall blackness of the image), contrast (the difference between light and dark areas), and spatial resolution (the ability to see fine detail). The kilovoltage peak (kVp) controls the energy of the X-rays and their ability to penetrate tissues, while milliampere-seconds (mAs) controls the quantity of X-rays produced. By adjusting these settings, radiographers can optimize the image quality and minimize patient exposure.