High Dose Rate (HDR) Brachytherapy for Gynecological Malignancies
The
word “brachytherapy”comes from the Greek word brachy meaning “close
by”, referring in this case to a radioactive source applied in or near the
tumor.
High
Dose Rate (HDR) Brachytherapy is often used in the treatment of
gynecological malignancies such as Cervix and Endometrial cancers. When combined strategically with external radiation, there is
potential for improved local control and reduction in both cancer and
treatment related morbidity. External
beam radiation therapy (EBRT) is usually administered first to the whole
pelvis. Then series of
brachytherapy procedures is performed immediately after completion of
external beam radiotherapy, depending upon the stage of disease
High
Dose Rate (HDR) Brachytherapy for Gynecological treatment uses various
applicators that enter either a cavity or tissues, based on the patient’s
stage of disease. In HDR Brachytherapy, a much higher activity radioactive
source is used. Applicators are
placed into the appropriate location in the Radiation Oncology department or
at times under anesthesia in the operating room. After the applicators are
placed, X-rays are taken to verify the position of the applicators and their
relationship to the adjacent bladder and rectum. The X-rays also assist the
physician in defining precisely where the radiation will be delivered. A 3-Dimensional volume and individualized treatment plan is
then generated to deliver a precise dose of radiation to the target area and
programmed into the computer. When
the patient is brought to the Radiation Oncology department, the applicators
are connected to the HDR machine. This
high activity source is welded onto the end of a cable which is a component
of the HDR Remote Afterloading System.
Through a computerized system, the radioactive source is then
directed into each of the applicators.
The HDR source dwells in predetermined positions for predetermined
times to give the prescribed dose to the area of interest.
After the treatment, the system automatically returns the radioactive
source into the protective storage unit of the remote afterloading machine.
This process is normally performed as an outpatient procedure and is
repeated a number of times depending on the stage of disease and the dosage
prescribed. The applicators are
then removed and the patient may resume normal activities.
There is no residual radioactivity left in the patients when she goes
home. High Dose Rate
Brachytherapy has significantly reduced the treatment time to merely
minutes, and has the capability of sophisticated conformation of dose to the
area of interest while limiting the dose to the surrounding normal tissues.
