Therapy
for lung Cancer
Radiation
therapy
Radiation therapy is the delivery of focused high-energy x-rays,
gamma rays or atomic particles. It affects cells that are rapidly
dividing such as cancer cells much more than those that are not. Most
cancers, including lung tumors, are made of cells that divide more
rapidly than those in normal lung tissue, holding out the hope that the
tumor can be eliminated without damaging surrounding normal tissues.
Radiotherapy acts by attacking the genetic material or DNAwithin tumor
cells, making it impossible for them to grow and create more cancer
cells. Normal body cells may also be damaged though less markedly but
they are able to repair themselves and function properly once again.
The key strategy is to give daily doses of radiation large enough to
kill a high percentage of the rapidly dividing cancer cells, while at
the same time minimizing damage to the more slowly dividing normal
tissue cells in the same area.
Chest
radiography
The chest x-ray
is the most commonly performed diagnostic x-ray examination. Approximately
half of all x-rays performed in medical institutions are chest x-rays.
A chest x-ray is usually done for the evaluation of lungs, heart and chest
wall. Pneumonia,
heart failure, emphysema,
lung
cancer and other medical conditions can be diagnosed or suspected
on a chest x-ray. Traditionally, chest x-rays have been performed prior
to employment, prior to surgery or during immigration. The use of "routine"
chest x-rays is being reevaluated because there is a lack of evidence
for their usefulness, and many insurance companies no longer pay for these
"routine" x-rays performed in the absence of specific signs,
symptoms or medical conditions.
Chest
MRI
Magnetic
resonance imaging (MRI) is a non-invasive way of viewing organs, soft
tissues, bone and virtually all other internal body structures. MRI uses
radio waves passed through a powerful magnetic field to produce clear
and detailed pictures of the chest, providing information on the heart
and lungs that cannot be otherwise obtained from an x-ray,
ultrasound,
or computed
tomography (CT) scan.
Chest
CT Scan
Computed tomography (also known as CT or CAT scanning) of the chest uses
special equipment to obtain multiple cross-sectional images of the organs
and tissues of the chest. CT produces images that are far more detailed
than a conventional chest x-ray. CT is especially useful because it can
simultaneously show many different types of tissue, including the lungs,
heart, bones, soft tissues, muscle and blood vessels. Modern CT scans
utilize a method called spiral (or helical) CT that captures images of
the chest from many angles and, with the aid of a computer, processes
the images to create cross-sectional pictures or "slices" of
the area of interest. The images can then be printed out or examined on
a monitor.
CT scanning is considered to be a "patient-friendly" procedure
because it involves relatively low radiation
exposure and is not invasive. Contrast
material is sometimes injected through a vein to make the blood vessels
and soft-tissue masses stand out. During the CT examination patients usually
lie flat on their back, but occasionally they may be asked to lie on their
side or on their stomach. Patients are periodically asked to hold their
breath. No preparation is required prior to the exam. Patients generally
do not require a sedative to remain calm. Radiofrequency Ablation of Lung Tumors
One of the most promising alternatives to surgical removal of lung tumors
is eliminating the tumor cells using heat. The technique, called radiofrequency
ablation (RFA), is performed by interventional
radiologists and is much less invasive than open surgery. Guided primarily
by computed
tomography (CT) scanning, a small needle electrode is inserted through
the skin and directly into the tumor tissue. Radiofrequency energy consisting
of an alternating electrical current in the frequency of radio waves is
passed through the electrode. The energy causes the tissues around the
needle electrode to heat up, killing nearby cancer cells. At the same
time, heat from radiofrequency energy closes small blood vessels and lessens
the risk of bleeding. RFA usually causes little discomfort. It is usually
done as an outpatient procedure that does not call for general anesthesia.
Needle
Biopasy
A nodule is defined as a relatively round lesion that is less than three
centimeters in diameter. A lung nodule is located within the lung itself,
not in the airways. A patient with a lung nodule usually experiences no
symptoms; the nodule is most often detected on a chest x-ray.
More than half of solitary or single nodules within the chest are benign,
or non-cancerous, usually due to a previous infection. However, all solitary
chest nodules are considered potentially malignant
until proven otherwise, and for this a needle biopsy may be required.
A biopsy involves removing a small piece of tissue for examination by
a physician. A needle biopsy, sometimes called a needle
aspiration, is the easiest way that tissue can be safely removed from
the body. The procedure, which is most often performed by a radiologist
or interventional
radiologist, involves a needle that is inserted through the skin.
The needle biopsy may use a syringe or an automated
needle to obtain the tissue sample.
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