Radiation Safety with Prostate Seed Implantation
Radioactive seeds remain in your prostate gland after your prostate seed implant. For this
reason there are certain safety measures you should take after your implant. These are
The number of prostate seeds used in a prostate seed implant varies with the size of the
gland. Each seed is about 1/8th inch long. The seeds are grayish silver in color. They
look like a piece of lead from a lead pencil.
Very rarely, a seed that is close to the urethra may come out in your urine or ejaculate.
Never touch prostate seeds with your fingers and ALWAYS flush down the toilet
bowl. If you pass a seed into clothing use a tweezers or spoon to pick it up. The
radiation in the seeds will not spread into the tweezers or spoon. If you pass a seed in a
condom, use a scissors to trim the condom and then flush the seed in the toilet. Passing a
few seeds will not affect your implant. If you pass more than a few seeds, call your
The radiation level in the seeds is strongest right after your implant. Over time, the
radiation levels lessens or “decays”. How long it takes for all the radiation in the seeds to
decay depends on the type seed used. The radiation doctor or nurse will talk to you about
this. The chart below may be helpful:
Percentage of Radioactivity in Seeds
Type of Seed Day of Implant 1 month after
3 months after
6 months after
12 months after
Iodine 125 100 71 35 12 2
You are not contagious. You will not spread radiation by sharing a toothbrush or shaking
hands. Little of the radiation from the seeds makes it out of your body. For this reason,
you will not pose much of a hazard to those around you.
You will have many seeds in your prostate gland. The radiation in your body will be
concentrated in your lower pelvis. For the most part, your body will act as a natural
shield. But there are some safety measures you should take in the first days to weeks after
your implant. These measures have to do with the amount of time you spend around
others. It also has to do with the distance you keep from others. These restrictions are
listed below. They apply if Iodine 125 seeds are used.
ξ Do not let infants or small children sit on your lap for more than 20 minutes per
hour during the first 3 months after the implant.
ξ Limit the time you spend close to pregnant women during the first 3 months after
the implant. You may hug and stand next to them for short periods of time, about
1 1/2 hours per day for the first 2 months, and 3 hours per day for the next month.
At distances greater than 2 feet, you may spend as much time with a pregnant
woman as you want.
ξ Do not “spoon” with your sleeping partner for several weeks after your implant.
You may want to sleep by yourself if there is any question of maintaining a safe
distance between you and your partner.
ξ Although there are no formal restrictions on your pets, you may want to use
similar precautions with them.
If other types of seeds are used, we will give you other instructions.
You will be given a card with information about the date and type of your implant. You
should keep this card in your wallet. The card will also include the name of your
radiation doctor. Keep this card and letter with you in the event of an emergency. Show
it to any doctor you consult over the coming months. You should also carry the card if
you will be in airports or traveling to Canada or Mexico.
If you should unexpectedly die before the radiation in the seeds is completely gone, your
family should contact the Radiation Oncology Department at (608) 263-8500. Special
handling of your body will be required.
Please call if you have any questions or concerns. The phone number for the Radiation
Oncology Clinic is (608) 263-8500. If you live outside of the Madison area, call
1-800-323-8942. If the clinic is closed, your call will be transferred to our answering
service. Ask to speak to the radiation doctor on call. The doctor will call you back.
Your health care team may have given you this information as part of your care. If so, please use it and call
if you have any questions. If this information was not given to you as part of your care, please check with
your doctor. This is not medical advice. This is not to be used for diagnosis or treatment of any medical
condition. Because each person’s health needs are different, you should talk with your doctor or others on
your health care team when using this information. If you have an emergency, please call 911.
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by the Department of Nursing. HF#6567.