Over the years, medical imaging has
become a vital part in the early detection, diagnosis and treatment of cancer. In some
cases medical imaging is the first step in preventing the spread of cancer through early
detection and in many cases makes it possible to cure or eliminate the cancer altogether. Computed Tomography (CT) imaging, Magnetic
Resonance (MR) imaging, Mammography, Nuclear Medicine (NM) imaging and Ultrasound
(US) imaging and X-ray imaging are all very important tools in the
fight against cancer.
After cancer has been diagnosed,
imaging is often used to follow the course of cancer treatment and to monitor the growth
or remission (disappearance of the signs of cancer). Medical imaging is being used
more frequently to build precise computer models which allow doctors to guide exact
radiation treatment of cancer (click here to go to the section
on radiation treatment planning using CT and MR data).
CT and MR are both exceptionally good
at imaging soft tissue structures, and thus are excellent for detecting and diagnosing
tumors and to differentiate if they are benign or malignant.
CT imaging is typically the
method of choice for imaging tumors of the lungs, abdomen, liver, kidneys, pancreas and
pelvis. This is due to its fast speed of data acquisition and thus its ability to minimize
disturbances (artifacts) in an image which may be caused by patient motion, breathing or
peristalsis (involuntary wavelike contraction of gastro-intestinal organs). CT can also be
used to look for tumors in the brain and spine. CT scanning is also being used more and
more to guide biopsy (sampling) of tumors in order to test if the tumor is benign or
malignant. Newer spiral CT scanners are being equipped with so called "Interventional
CT" packages to allow real time CT imaging for the guidance of biopsy.
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|
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| The
radiologist uses "real-time CT guidance" to guide biopsy of a tumor,he can watch
on the progress of the needle placement on the monitor as he approaches the lung tumor. |
|
Axial CT
image of the liver and kidneys shows a benign (non-cancerous) cyst (arrow) |
MR imaging has excellent contrast resolution, meaning it can
show a subtle tumor or soft-tissue growth with exceptional clarity. Thus, MR is often the
method of choice for diagnosing brain tumors and for searching for metastases (cancers
which have spread from another organ) of the spine. MR is also an excellent method for
imaging tumors in joints and bones. New, faster MR acquisition techniques are also
allowing MR to be used more often to image cancer of the liver and abdomen.
 |
This axial MR image of the brain
shows a large tumor in upper left corner of image (arrow) |
Nuclear Medicine imaging (including Positron
Emission Tomography, PET) is often used to search for cancer in the organs and the
skeletal system. The nuclear medicine "bone scan" is a routine examination for
this purpose.
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| This nuclear
medicine bone scan is normal and shows no cancer |
Ultrasound imaging is a versatile technique for searching
for abdominal tissue masses if a patient has symptoms of abdominal pain. Ultrasound can
also be used to guide biopsy (sampling) of tumors to test if they
are benign or malignant.
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| This digital x-ray image shows a
normal stomach |
Various types of x-ray
imaging are central to diagnosis of many types of cancer. Fluoroscopy is useful
for detecting disorders and tumors in the upper gastro-intestinal (GI) system (for
example, the stomach and intestines). Chest x-ray is often the first step in detecting
lung cancer and mammography is the primary
means for detecting and diagnosing breast cancer.
Updated: June 9, 2008
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