X rays are traditional imaging and may be the first
type of imaging performed. Mammography is a form
of x ray; it is the screening and diagnostic examination
used to detect breast cancer. Chest x rays may be used
to detect lung cancer. Other types of x rays may be
used in cancer diagnosis.
Computed tomography (CT) scanning. Because the
use of the computer can generate finer, cross-sectional
detail in combination with x rays, CT scans often are
used to image a particular area. And CT scans have been
used to screen for lung cancer, though the practice still is
in debate. CT colonography can screen for polyps and
other lesions in the large intestine, much like a colono-
scopy. But CT is noninvasive, meaning it does not pen-
etrate the skin or enter the body. CT may involve use of
contrast that is injected tohelp make certain fluids or
tissues more visible on the image for the radiologist.
Nuclear medicine or radionuclide scans involve
injection of a small amount of a radiopharmaceutical
into a vein. The agent flows through the bloodstream
and collects in certain areas or organs. When a special
camera is used to take images, the agent will show in
‘‘hot spots,’’ which the radiologist will use to interpret
the results. Often, nuclear medicine scans will be used
to check for spread of cancer to bone, but they also
have other uses. Most of the radiopharmaceutical
passes out of the body in urine or stool and the rest
disappears through natural loss of radioactivity over
time. Reaction to the agent is rare.
Ultrasound is an imaging examination that does
not use radiation. Instead, high-frequency sound waves
are used to produce images. Ultraound often is used to
follow up in suspicious mammogram findings. Ultra-
sound images show fluids and soft tissues very well and
often help radiologists determine if a mass is most likely
a benign cyst or a malignant (cancerous) solid mass.
Other common areas that ultrasound is used to image
when diagnosing cancer are the thyroid, the abdomen,
the pelvic area (ovaries, uterus), and the prostate.
Magnetic resonance imaging (MRI) also does not
require use of radiation. Instead, a strong magnetic
field and radio waves provide clear and detailed pic-
tures through a computer display. MRI has proven to
be the most sensitive examination for brain tumors.
MRI also has become increasingly useful in breast
cancer imaging in recent years, as well as for many
other suspected cancers.
Positron emission tomography, or PET, scanning
is a nuclear medicine procedure that acquires images
based on detection of radiation, as in a radionuclide
scan, but through emission of positrons. Positrons are
tiny particles emitted from a radioactive substance
administered to the patient. Cancer cells sometimes
show up as areas of high activity. In recent years,
physicians have been able to combine these images
with CT images, fusing them with one another to
show superb detail of the anatomy from CT scans
along with the functional details gained from PET.
These images improve diagnosis, staging, and tracking
of treatment progress for cancer patients.
In most cases, at least for cancers that are solid
tumors, a biopsy is the only definite method for con-
firming cancer diagnosis. Before many of the imaging
methods discussed above were developed, a biopsy only
could be performed through surgery, where a small
sample of the tissue was cut out and sent to a laboratory
for evaluation by a pathologist. Today, these samples
can be extracted using small needles. The physician can
be guided to the site of the suspected cancer by use of
ultrasound, CT, MRI, or other imaging methods. The
biopsy method often is called fine needle aspiration
biopsy or core needle biopsy. Biopsies also may be
performed during surgery, particularly to verify and
stage cancer when a mass is removed as part of treat-
ment. Removal and biopsy of the entire tumor is called
excisional biopsy, while removal of only a portion of
the tumor is called incisional biopsy.Treatment
Planning treatment for cancer first involves stag-
ing of the cancer. Once the physician has gathered the
information needed to determine the cancer’s stage,
the physician will communicate with the patient about
treatment options. The most common treatments for
cancer are chemotherapy, radiation, and surgery. A
cancer patient may receive one or all of these treat-
ments or a combination of them in any order. The
particular use and details of each treatment depend
on the type of cancer, the stage, and many other
factors individual to each patient.Staging
Cancer staging determines the extent of the cancer
in the body. It usually is based on the size of the original
tumor, whether the cancer has spread to the lymph
nodes, and whether the cancer has spread to organs of
the body that are distant from the original site. Each
cancer has its own staging system using letters and
numbers. The T in cancer staging describes the original
tumor and the N stands for whether the cancer has
spread to nearby lymph nodes. The M stands for meta-
stases, or distant spread of the cancer. Numbers area
assigned along with the letters. Stage I cancers are the
least advanced and have the best outlook for survival.
Stage IV is the most advanced level. A cancer’s stageCancer