Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Absorption and X-ray Spectrum

Description

This lecture covers the fundamentals of biomedical imaging, including the invention of computed tomography, CT imaging of animal models, and the concept of absorption in the real world. It also explores the energy spectrum of an x-ray tube and the consequences of energy-dependent absorption.

In MOOC

Fundamentals of Biomedical Imaging: Ultrasounds, X-ray, positron emission tomography (PET) and applications

Official source

Quiz

Ontological neighbourhood

Health sciences

Radiology: Topics in radiology

Related concepts (26)

CT scan

A computed tomography scan (usually abbreviated to CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or radiology technologists. CT scanners use a rotating X-ray tube and a row of detectors placed in a gantry to measure X-ray attenuations by different tissues inside the body.

X-ray

X-ray radiation, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 nanometers to 10 picometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3e16Hz to 3e19Hz) and energies in the range 124 keV to 145 eV, respectively. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays.

Medical imaging

Medical imaging is the technique and process of imaging the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). Medical imaging seeks to reveal internal structures hidden by the skin and bones, as well as to diagnose and treat disease. Medical imaging also establishes a database of normal anatomy and physiology to make it possible to identify abnormalities.

X-ray spectroscopy

X-ray spectroscopy is a general term for several spectroscopic techniques for characterization of materials by using x-ray radiation. When an electron from the inner shell of an atom is excited by the energy of a photon, it moves to a higher energy level. When it returns to the low energy level, the energy which it previously gained by the excitation is emitted as a photon which has a wavelength that is characteristic for the element (there could be several characteristic wavelengths per element).

Positron emission tomography

Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, regional chemical composition, and absorption. Different tracers are used for various imaging purposes, depending on the target process within the body. For example, -FDG is commonly used to detect cancer, NaF is widely used for detecting bone formation, and oxygen-15 is sometimes used to measure blood flow.

Related lectures (32)

Gamma and Neutron Radiography

Explores the historical development and industrial applications of radiography and computerized tomography with X-rays, gammas, and neutrons.

Attenuation Correction MOOC: Fundamentals of Biomedical Imaging: Ultrasounds, X-ray, positron emission tomography (PET) and applications

Explores the fundamentals of attenuation correction in biomedical imaging and simplifies the process using the geometric mean at 180°.

Attenuation Correction in PET MOOC: Fundamentals of Biomedical Imaging: Ultrasounds, X-ray, positron emission tomography (PET) and applications

Covers the fundamentals of attenuation correction in PET imaging and why PET/CT is the industry standard.

Overview and comparison: Imaging Modalities MOOC: Fundamentals of Biomedical Imaging: Magnetic Resonance Imaging (MRI)

Covers the comparison of bio-imaging modalities, discussing contrast mechanisms, limitations, SNR, and reconstruction techniques.

Medical Imaging: Techniques and Applications