The Treatment Process
create a three- dimensional image of the prostate to help guide seed
placement. In this image, the prostate
gland is in red, the urethra in green, and the rectum in orange. Blue
area shows where high-dose radiation will be delivered.
Unlike external beam radiation therapy, which delivers a high dose of radiation from outside the body,
brachytherapy is a low energy type of radiation therapy in which small radioactive
sources, commonly called seeds, are permanently implanted inside the tumor.
On average 60 to 120 seeds are placed in a pattern specific to each patient's prostate
gland, and remain there as a permanent implant. The seeds are smaller than a grain
of rice, measuring only 4.5 mm in length and 0.8 mm thick. The seeds deliver
most of their dose in about 4-6 months and the remainder of the dose by the end of
the first year. The seeds contain temporarily radioactive material inside titanium
shells. Titanium is well tolerated by the body and is used for many other procedures
such as joint replacements. The seeds are permanent and cause no discomfort.
The first step in the process is an outpatient consultation with a radiation
oncologist, who will work closely with the patient and his multidisciplinary team.
The consultation will include a review of the medical history, imaging, and a
physical examination. The radiation oncologist will then discuss the suitability
of implant therapy based on PSA, Gleason score, tumor stage and other factors.
The pale purple circle on the left side of the prostate outlines the exact location
of the tumor. The green circle around it shows the area of higher-dose radiation
from the seeds delivered to the tumor.
Patients also undergo blood work and other preoperative studies before the day of
the implant in order to be approved for anesthesia.
At the University of Maryland Medical Center, all prostate brachytherapy patients
undergo blood work and other preoperative studies before the day of the implant
in order to be approved for anesthesia. On the morning of the procedure, patients
receive an enema to help maximize the quality of the ultrasound images. Blood
thinners are discontinued prior to the procedure date to help diminish bleeding.
Day of the Procedure
On the morning of the procedure, patients may receive an enema to clear out
the lower part of the bowel. Patients are asked to arrive about two hours before
the scheduled prostate implant. Typically the patient receives general or spinal
After the patient is anesthetized, an ultrasound probe is carefully placed
and positioned to view the entire prostate. Axial images of the prostate, the
urethra and the rectum are taken and transferred to the treatment planning computer.
The computer evaluates the exact position of the prostate and generates a three-dimensional
plan that dictates the precise placement of the needles and seeds to provide
exactly the amount of radiation needed to cover 100 percent of the prostate
gland while limiting the amount of radiation to the normal structures (such
as the urethra and the rectum).
The Implant Process
the day after the seed implant, doctors take a CT scan of the prostate to
ensure that the seeds are properly placed. The image shows the cancerous
area targeted by a higher dose of the radioactive seeds.
Using the plan, the radiation oncologist places the seeds inside the prostate. There
is no surgical incision; instead, the seeds are loaded within fine needles which are
inserted through the perineum (the area between the scrotum and the anus) into
the prostate gland. The needle can be seen on the ultrasound image and is guided
to the planned position within the prostate. It is then withdrawn, leaving the seeds
at the exact locations. After the seed placement, the urologist performs a cystoscopy
(a test that allows the urologists to look at the interior lining of the bladder and
the urethra) to look for and remove any seeds in the bladder or the urethra and to
assess whether a catheter is temporarily needed. The placement of a catheter is rare.
The patient is then transferred to the recovery room. The entire procedure takes
about two hours.
After the Procedure
After the procedure, the patient will spend several hours in the recovery room.
Patients generally are able to return to work within two days of discharge.
Radiation exposure to other people is minimal; restrictions are recommended if the
patient is returning to a setting where a newborn child, pregnant woman or young
people are present.