Canadian Cancer Statistics 2013. Cancer in Canada.

Canadian Cancer Statistics 2013




Cancer in Canada

MONITORING ORGANS: Cancer

Why Use Imaging?• non-invasive way of:– Screening for cancer

• ex. mammograms for breast cancer– Diagnosing/staging

• ex. location in the body, spread, guiding a biopsy– Guiding cancer treatments

• ex. focus on the tumors and minimize damage to surrounding tissue

– Determining if a treatment is working

– Monitoring for cancer recurrence

1. Ultrasounds

• Use of sound above human hearing range to image body structures, including soft tissues

• Sounds waves are reflected (echo) off of different density tissues differently

2. X-Rays• Oldest form of imaging

• Found by German physicist Wilhelm Rontgen, 1895

• High-energy electromagnetic waves that pass through soft tissue (ex. muscle) but are absorbed by dense tissue (ex. bone)

• Can also be used to see soft tissues with the help of stains (ex. bismuth)

Most popular use:

• Dental x-rays

An aside...

Electromagnetic radiation- Forms of energy, some on the visible spectrum

(light)

• Some can be damaging to our DNA, in particular high-energy high-frequency waves (above colour spectrum)

3. CAT Scans: computerized axial tomography scan

• An X-ray machine rotates around the patient taking hundreds of individual pictures form many angles

• More sensitive than an X-ray alone

• Computer re-assembles the picture into a 3-D image, allowing for organs to be viewed section-by-section

• Full body scans are still not routinely done due to high incidence of “incidentalomas”, not real issues that show up as issues on the scan

• Known to increase chances of cancer in children…

4. MRI (Magnetic Resonance Imaging)• uses radio waves and a strong magnet

• different tissues (including tumors) emit a more or less intense signal based on their chemical makeup

• produces a three-dimensional images of sections of the body

• MRI is sometimes more sensitive than CT scans for distinguishing soft tissues.

• can use radioisotopes (unstable atoms) that are injected into the target organ for imaging

5. PET (Positron Emission Tomography)

• used to locate a tumor

• the patient is given an injection of regular sugar and a small amount of radioactively labeled sugar

• because cancer cells take up sugar more than other tissues in the body the tumor is easier to find

• large amounts of radiolabelled sugar collect at site of damage “lighting” it up

• PET scans are beginning to be used to check if a treatment is working - if tumor cells are dying they use less sugar

Canadian Cancer Statistics 2013. Cancer in Canada.

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