Radioactive after FDG injection????

SoCalGal · 03-14-2010, 04:06 PM

Is is true that once you've had the petCT FDG injection, during that "hour, sit still and wait" period you are radio-active and should NOT have a friend sitting with you?

And if this is true why wouldn't you be radioactive for 24 hours? Or some other arbitrary time frame?

This was never mentioned in the (8) years of prior scans at the hospital. Now I'm at my oncologist's facility and the woman in charge there is adamant that I must sit alone.

Does anyone know any FACTS on this? My scan is at 7:30 tomorrow morning, which would have been barely tolerable before the time change. In Flori time 7:30 AM is the same as 4:00AM...

Colleen007 · 03-14-2010, 06:14 PM

I can only share what I have experienced...my husband comes with me to every scan and for the PET w/ FDG, he has to wait in another room. In fact, the tech who injects the FDG leaves me alone it the room (with a big "radioactive" sticker on the door) and comes back to get me when it is time to go in the machine. I suggest you bring a book, iPod or something to kill the time for the hour.

I also question the timeframe because nobody has ever said my husband couldn't be in the confined space of our car to drive me home afterwards...but, it is what it is. Since you have to fast prior to the scan, maybe a lunch date with your friend would be in order afterwards :-)

Good Luck!

Jackie07 · 03-14-2010, 06:17 PM

Flori,

I have not checked on any studies. But I can share what I've experienced so far in our facility.

Once we have checked in at the desk of the PET scan office in the Nuclear Medicine department, we are led to a waiting room with a changing area and lockers to put our clothing/purse.

Everyone in the waiting room are in their hospital gowns. It probably would be awkward for others to be encountering someone else's friend in 'plain' clothes and listening to their conversation as the room is indeed small.

I know the funny feelings when we are forced to be sitting next to strangers in a confined environment. I usually just read magazines. Sometimes I was able to start a conversation if there happened to be an eye contact. Often time I could help relieve/add to the fear of one of the patients because I am a multiple cancer survivor who has experienced recurrences.

I honestly doubt (I will check it out and then report back) that being radioactive is the main issue here. I've read that for a day or two, there could be color change in the urine - proof that there is still someting in our system after our scan.

Nobody has ever ask us not to get a ride/not to go to public bathroom/not to take the hospital elevator after our scan, so I think the issue rests in the area while we are waiting. But if there's really an issue of being 'radioactive', all the patients probably are not supposed to be sitting together compounding the radioactivity.

What an interesting question! I'd like to know the answer, too.

Jackie07 · 03-14-2010, 06:32 PM

http://www.epa.gov/radiation/understand/pathways.html

Darlene Denise · 03-14-2010, 06:43 PM

Flori: Does this info below help? I read a few things and it appears it can be in your bodily fluids a few hours after?! I guess you shouldn't pee on yourself or your companion! I always take my mother and she sits with me. They only seemed concerned that we will talk which is a no, no.

Interesting, just one more damn thing to worry about, like we don't have enough. I will hope for good PET results for you. I'm having my noggin scanned on the 22nd and scanxiety has the best of me!

Patients who have PET scans do become radioactive for a short period of time. For most PET studies, radioactive material is injected into the patients an hour or two before the procedure. After patients have had the scan, they may still contain some of the radioactive material. The remaining radioactive material does not stay in them very long. Based on some information from a National Council on Radiation Protection and Measurements Report (Report No. 124), if you're about three feet from the patient an hour after the PET scan, you receive 0.004 rad/hour. This means if you stood at three feet from the patient for one hour, you would receive 0.004 rad (a rad is a unit of radiation dose).

naturaleigh · 03-14-2010, 07:18 PM

Hey Flori,

Everytime I have a Pet they tell me I am radioactive for 24 hours and should not be around woman who are pregnant, small children or the elderly. I am also told to drink alot of water and flush twice everytime I use the restroom.

Henny · 03-14-2010, 09:11 PM

Well speaking as a Nuc Med Tech..the Fluorine-18 in the sugar has a half life of 2 hours-so every 2 hours half of it is gone. It is considered completely gone after 10 half lives or 20 hours.
I would have the patients (including myself when I had my scans) rest in a lead lined room. This was only to keep the radiation exposure down for the techs who worked with it every day.
I also let family members who were adults and not pregnant in the resting room for the 1-2 hour uptake time. If there was a pregnant family member or children I had them wait in the regular waiting room. My physicist calculated that the person in the resting room with the patient would not have any measurable exposure.
And like everything in life we have to measure risks vs benefits. Sometimes a person would be so freaked out by having a scan they couldn't do it without their support person
Hope this helps

Henny

Henny · 03-14-2010, 09:16 PM

PS- the water thing isn't necessary since the sugar is already taken up in the cells and doesn't leave through unine-and while I'm at it, the only thing you really need to take in fluids after is a contrast CT scan. No more drinking and peeing for bone scans. The literature says it doesn't help the scan.
H

04-15-2010, 04:20 PM

You are right to be concerned. However, If your friend sits 2 meters away from you after the injection of FDG, their dose will be greatly reduced. The FDG does have a half life of 2 hours (well, 110 minutes) and the dose will be half decayed after 2 hours. But-- you also excrete the FDG in your urine. So more than half of it is gone from your body after 2 hours, if you urinate. I just checked a patient last week 2 hours after her FDG injection, and she was giving off a little radiation, but not a lot more than background. You do want to be careful around pregnant women, because it's always better to be safe than sorry. Children and fetal tissue are more sensitive to radiation (because their cells are dividing faster than older people's.)

Do you know how much FDG you are getting? The dose can range from 10-20 millicuries, which gives a bystander a much different dose.

Hope this helps.

04-15-2010, 04:41 PM

Please do drink a lot of water after your scan. FDG is taken up by your cells, but it is then metabolized and excreted. If you ask to look at your scan after it is taken, you will see a "hot spot" where the bladder is, if urine has collected there.

The woman who was adamant about not letting another person in with you was probably being overzealous. Like the person earlier said, you must weigh the risk against the benefit.

Good luck! Ask your facility; they probably have a radiation safety officer (as I am) who can help answer your questions.

Chelee · 04-15-2010, 05:33 PM

When I have a PET/CT I'm told nobody is allowed back there with me and they are adamant about it! No talking, reading, nothing. I really put some pressure on them to see if I could at least read a book if I didn't move? The answer was no. I thought they were kidding but they weren't.

So after I change clothes & get comfy in my chair they will give me a blanket to stay warm. Then once I get the injection they turn off the lights in this room and tell me they will be back to get me in about 1 hr. So I usually nod off since I'm not allowed to anything. Once the PET/CT is done they have never told me to stay away from kids or adults. The only thing they have told me each and every time is to drink plenty of water as they are handing me a bottle. It's interesting how these places are so different.

Chelee

hutchibk · 04-15-2010, 05:46 PM

Twinky - I have always been seated in a single chaired 'resting' room with a "radioactive" sticker on the outside of the door. Companions are always directed to sit out in the waiting room... my scan clinic has always just handled it so low key and matter of policy, that I never stopped to think that I might be radioactive, and that part of the reason that the techs leave me alone 'to rest' is not only so that the FDG does it's work most efficiently in a resting body, but so that they are exposed to the most minimal amount of radioactivity. But it makes perfect sense now.

Also, I just learned in a thread a couple of weeks ago that some scan clinics give PET recipients a card to carry if they need/plan to travel on an airplane within 24 hours of having the injection... so that if they show up at security as being 'radioactive' ~ they have their doctor's note explaining why...

ElaineM · 04-15-2010, 09:17 PM

What an interesting discussion !!
When I had a pet/ct scan the technicians allowed me to use the public restrooms whenever I wanted. However they took me to a small room for about an hour and half after the injection and before the scan. They asked me not to move around, talk, read, eat, do needlework or any other activity. I was allowed to drink water though. I use prescription eye drops, so when it was time to use the drops the technicians came into the room and put the drops in my eyes and wiped the excess drops in the area around my eyes for me.
A technician took me out to the front lobby of the hospital for me to meet my ride after the scan. She asked me to stay away from pregnant women for 24 hours. I guess she wasn't thinking. All kinds of people including pregnant women walk around hospital lobbies.
The technicians told me moving around too much after the injection and before the scan allows the radioactive contrast to get stuck in the muscles and they don't get accurate results.
The injection for bone scans is radioactive too, but the guidelines are not nearly as strict. However once after a bone scan injection the technician thought he gave me too much and came running out to the waiting room to find me. He told me he had to check my radiation levels, because he tought he gave me too much. You should have seen all the other people in the small waiting room scatter !!!!!!!!!! The waiting room quickly turned into a private waiting room just for me. I was okay and the levels were within the proper range.

naturaleigh · 04-16-2010, 06:04 AM

This is so mind boggling how things differ so much with these scans. I have always gone alone to all my treatments so I guess the isolated part was never an issue with me. But, every time I go to a PET scan I have always been given magazine to read if I don't have a book. Next time, if there is a next time, I might try to take some cross stitch just to see what they tell me.

I have never been asked if I were traveling any where, so I wonder if my facility has these tags I have been reading about on this site.

naturaleigh · 04-16-2010, 06:08 AM

OH, another thing I am told to do is to get as much exercise as possible afterwards. They say it is supposed to help with the half life. After my treatment, I usually go outside and rake to avoid being indoors. I guess that is my train of thought with them telling me to avoid people especially the elderly. Since I live with my elderly father, I don't want to be indoors with him and have the radation trapped inside. Should I not be raking after having radioactive scans done?

StephN · 04-16-2010, 11:51 AM

From my first PET scan in 2000 (BTW it was in "investigative mode" those days - new software or something) I have always had to stay in a small room ALONE with the lights down. With my head and neck supported and relaxed. I wanted to read and had a book, but the tech said I could only read for the first 20 minutes then came and made sure I put the book away the lights were even lower. They say it is OK to nap or drift off.

Reasoning is, like someone else mentioned, they want the contrast to distribute evenly in your tissues and holding a book will interrupt up take into the chest wall if those muscles are in use.

I am always asked to empty my bladder on the way to the scanner so that I DO NOT have so much of a hot spot in that area of my scan. (The same was asked of me for my recent bone scan.)

Sort of surprising that there is not a more standard protocol on this scan...

hutchibk · 04-16-2010, 06:26 PM

Steph - your experience sounds exactly like mine... and many on this thread seem to have a commonality to them, so maybe it is fairly standard procedure. I did have one once (in a horrible mobile truck) that when they booked it told me that the fasting diet was overly trumped and really not necessary. That was just hogwash.

12-17-2010, 02:24 PM

Since 2005 my wife has had 9 PET Scans. During the first scan I was told that I had to wait in the waiting room. After that I had a meeting with one of the hospital administrators and insisted that I be allowed to stay and they were ok with it. I have been with her for each one since then. Keep in mind that if you have a child that is being scanned, they expect a parent to stay with them so haw dangerous can it be? Also, they do try to limit activity particularly if they are scanning for brain cancer because if the brain is "working or active" it will increase the FDG uptake in the same manner as cancer.