18 Questions
Which imaging technique uses radiation for cancer and tumor treatment?
CT Scan
What type of waves are used in ultrasound for medical diagnosis?
Sound waves
Which imaging technique relies on the principle of detecting differences in tissue density?
X-ray
In medical physics, what branch deals with applying physics principles to diagnosing and treating abnormal tissues?
Medical Physics
What revolutionary discovery by Wilhelm Conrad Roentgen opened new avenues in science and medicine in 1895?
X-rays
How does CT scan differ from conventional X-ray in terms of imaging technique?
CT scan is based on tissue density variations, while conventional X-ray isn't
What happens to the small magnets in the patient's tissue when a current pulse is applied?
They are disturbed from their parallel arrangement.
How is the released energy from the small magnets detected in the patient's tissue?
As an electrical current
What does X-ray imaging rely on for visualizing the different parts of a patient's body?
Absorption of X-rays
How do differences in body tissue densities help in creating images with X-ray technology?
By blocking X-rays effectively
What transformation occurs to the electrical current detected from the patient's tissue during imaging?
It is transformed into an image via a computer.
Why do protons in different brain tissues give off different amounts of energy during imaging?
Due to variations in tissue type
What happens when an X-ray strikes calcium in cortical bone?
It is blocked, causing the bone to appear white on the radiographic image
What causes the lung to appear darker, almost black, on a radiographic image during an X-ray procedure?
The air-containing space allows X-rays to pass through easily
What makes a fracture line appear dark while the intact bone appears white on a radiographic image?
The intact bone blocks more X-rays
In a CT scan, what is the role of the rotating X-ray source and detectors?
They rotate simultaneously in opposite directions to create multiple detailed images
How does a CT scan differ from a regular X-ray procedure?
CT scans use computers and rotating X-ray machines to create successive images along different directions
Why do CT scan images provide more detailed information compared to normal X-ray images?
CT scans make many successive images along different directions using rotating X-ray machines and computers
Study Notes
Medical Physics and Imaging
- Medical physics is a branch of physics that deals with the applications of principles of physics to medical diagnosing and treating abnormal tissues.
- The discovery of X-rays by Wilhelm Conrad Roentgen in 1895 opened a path to a new interdisciplinary branch, medical physics.
Medical Imaging
- Medical imaging refers to several different technologies that are used to view the human body in order to diagnose, monitor, or treat medical conditions.
- Imaging techniques can be categorized into electromagnetic (optical, X-ray, magnetic resonance imaging (MRI), thermography), acoustic (ultrasound), chemical, and electrical.
MRI
- MRI uses the magnetic property of water to create an image.
- A current pulse is applied to the patient's tissue, disturbing the parallel arrangement of small magnets.
- When the current pulse is off, the small magnets return to their parallel arrangement, releasing energy that they absorbed from the pulse.
- Different tissues in the body give off different amounts of energy, which is detected by a special device and transformed into an image via a computer.
X-ray Imaging
- X-ray imaging is based on the absorption of X-rays as they pass through the different parts of a patient's body.
- Differences in the densities of body tissue allow us to see inside the body by creating a shadow gram.
- The higher the atomic number, the denser the element and the more effectively the X-ray is blocked.
- Examples of X-ray absorption include:
- Calcium in cortical bone, which appears white on the radiographic image
- Less dense elements like nitrogen, which appear darker on the radiographic image
CT Scan
- A CT scan uses computers and rotating X-ray machines to make many successive images (called tomograms) of the inside of the body along different directions.
- The X-ray source and the detectors rotate simultaneously in opposite directions.
- A motorized table moves the patient through a circular opening in the CT imaging system.
- The CT scan images provide more detailed information than normal X-ray.
Learn about how X-rays interact with different types of tissues in the human body on a radiographic image. Understand why bones appear white, while less dense elements like air appear dark or black.
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