The physics behind medical imaging

Physics gave rise to technologies that allow us to see inside the human body without surgery. Developed during the 20th century, these techniques rely on X-rays, particle emissions, ultrasound detection, or magnetic fields.

Written by

Cassiopée Cunibil

PublishedFebruary 18, 2021UpdatedMay 16, 20261 min read

Radiography, the first medical imaging technique (see above), is the most widely used method for examining the skeleton. To visualize blood vessels, doctors perform angiography. This requires the injection of a contrast agent (usually iodine), which absorbs X-rays.

Scintigraphy is a nuclear-medicine technique: it uses radioactivity for imaging and for treating patients. Patients are given a radioactive tracer that binds to an organ or whose components are carried along by a flow. The tracer emits photons, which a camera detects. This makes it possible to track flows or observe an organ's function in real time.

Ultrasound is used in ultrasound imaging. The echo reflected by the organ is used to reconstruct an image in real time. Easy to use, ultrasound is increasingly being used for 4D imaging (3D representations of organs in motion), mainly to visualize heart motion and fetuses. As with MRI, neither a radioactive tracer nor a contrast agent needs to be injected into the patient.

The first radiograph ------------------------

Discussion

Comments

Join the discussion

No comments yet. Be the first to respond.

On the same theme

Articles recommended for you.

Knowledge

The mathematics of medical imaging

Medical imaging is an indispensable tool for physicians, whether for diagnosis, prognosis, or surgery. It provides anatomical or functional information about an organ or part of the human body while being either noninvasive or only minimally invasive.

Vincent BarraFeb 18, 2021

Knowledge

Medical imaging: picturing disease

The spectacular advances in medical imaging in recent years have come from combining mathematical ingenuity with computing power, drawing on theories devised long before they found practical applications.

FRANCOIS LAVALLOUFeb 23, 2016

Tomographic reconstruction

How can we use computed tomography or magnetic resonance imaging (MRI) to see inside the human body without opening it up or cutting into it? That is the true mathematical challenge of tomographic reconstruction!

CHRISTOPHE TILMANTFeb 18, 2021

“A better understanding of how the brain works”

Dr Christophe Habas is a neuroradiologist. He heads the medical imaging department at the Quinze-Vingts Hospital in Paris. His work combines hospital practice, research and university teaching. He has an in-depth understanding of the role mathematics plays in medical techniques, which he kindly agreed to share with us.

BERTRAND HAUCHECORNEFeb 18, 2021