RE: incontinent patient dosed with ~100 mCi of I-131

["North, David" <DNorth@Lifespan.org>]

Just to update the discussion with some more recent information which could
make a difference.....

We have studied over 200 patients who have been treated with I-131 for
thyroid cancer. The average effective half-life of the "extrathyroidal"
iodine in the body which we've seen (estimated by external exposure rates)
is actually about 17 hours with wide variations among patients. Eight hours,
or 0.32 days from Reg Guide 8.39, is roughly the minimum. That 0.32 day
figure, or ones similar to it, can be found in the literature going back
fifty years, and do not really apply because they are derived from euthyroid
populations. The Ca patients are all severely hypothyroid at the time of
treatment (or they should be!) which retards excretion. So, it is probably a
good idea to rely on some measurements for determining when to remove any
Foley catheter and discharge the patient. She could be excreting that iodine
more slowly than one might think.

David L. North, Sc.M. DABR
Associate Physicist
Department of Medical Physics
Rhode Island Hospital
593 Eddy St.
Providence, RI 02903
ph: (401)444-5961
fax: (401)444-4446
dnorth@lifespan.org


> ----------
> From: 	Krueger, Mark D CPT EAMC
> Reply To: 	radsafe@romulus.ehs.uiuc.edu
> Sent: 	Tuesday, June 20, 2000 08:12
> To: 	Multiple recipients of list
> Subject: 	RE: incontinent patient dosed with ~100 mCi of I-131
> 
> This is a great topic.  I appreciate all the comments.  This case has many
> gray areas.
> 
> Important clinical questions:
> 1.  How incontinent is the patient?  Many older patients, especially
> females, wear Depends for occasional stress-induced (coughing, laughing,
> exertion) incontinence.  However, some patients rarely have an "accident".
> If they do have an accident, they often lose only a small amount of urine.
> 
> 
> 2.  What is the patient's assumed biological I-131 half-life?  NRC
> Regulatory Guide 8.39, Release of Patients Administered Radioactive
> Materials, Appendix B, provides very conservative sample calculations.
> The
> NRC's conservative estimate of the effective half-life of the
> extrathyroidal
> component is 0.32 days.
> 
> Based on this information, I recommend the following:
> 
> 1.  Definitely admit the patient for therapy.  No outpatient ablation in
> this case.
> 
> 2.  If the patient is moderately or severely incontinent (requires
> frequent
> diaper changes), place a foley bladder catheter.  Have nursing personnel
> instruct patient how to empty the collection bag.  This eliminates health
> physics personnel from repeatedly entering the room and risking spread of
> contamination in unrestricted areas.  If patient is mildly incontinent,
> have
> patient collect the pads/diapers for storage and decay.
> 
> 3.  As always, highly encourage drinking extra fluids and urinating
> frequently.  To eliminate the need for nursing personnel to enter the
> room,
> I recommend against starting an IV drip unless absolutely clinically
> warrented.  Discharge patient after 3 days.  This represents 9 biological
> half-lives using the extrathyroidal component.
> 
> 4.  Upon discharge, instruct patient to immediately change the
> pads/diapers
> should there be a wetting incident.  The patient is an adult, not a baby.
> Therefore, he/she will know if they're wet.  I recommend the patient
> dispose
> of this waste in his/her regular household waste.  At this point (4 days
> post-dosing), most of the extrathyroidal I-131 has been excreted. Urinary
> excretion after 9 effective half-lives have passed (3 days) will be
> relatively minimal (less than 1 mCi).
> 
> 5.  I would not recommend canceling the ablation since the benefits of the
> therapy far outweigh the potential complications.
> 
> Sincerely,
> Mark D. Krueger, RPh, BCNP
> CPT, MS
> United States Army
> Clinical Nuclear Pharmacist
> Dwight D. Eisenhower Army Medical Center
> Fort Gordon, GA  30905-5650
> phone: (706) 787-2196
> FAX: (706) 787-2181
> E-mail:  mark.krueger@se.amedd.army.mil
> 
> Disclaimer:
> The opinions or assertions contained herein are the private views of the
> author and are not to be construed as official or reflecting the views of
> the US Department of the Army or the Department of Defense.
> 
> -----Original Message-----
> From: David W Lee [mailto:lee_david_w@lanl.gov]
> Sent: Monday, June 19, 2000 4:42 PM
> To: Multiple recipients of list
> Subject: RE: incontinent patient dosed with ~100 mCi of I-131
> 
> RADSAFERS:
> 
> Stupid question #3 or #4 so far on this thread.  If this incontinent 
> patient's attending physicians already agree/know that the patient is 
> incontinent, what is so difficult about catheterizing the patient and 
> collecting the radioactive urine in a bag/bottle which could then be 
> periodically poured down the hospital commode by a hospital radiological 
> control technician supporting this operation?
> 
> Best regards  David W. Lee, Radiological Engineering Team Leader, Los 
> Alamos National Laboratory (lee_david_w@lanl.gov), PH: (505) 667-8085; 
> FAX:  (505) 667-9726
> 
> >  I assume your patient has thyroid cancer, has undergone a sub-total
> >thyroidectomy and you are treating her with 100 mCi (2.7 GBq or 2700 MBq)
> of
> >I-131 to ablate post-surgical  thyroid tissue remnants, or you are
> treating
> >post-thyroidectomy metastatic disease.  In this case, you would expect
> the
> >patient to excrete >95% of the administered activity, primarily through
> the
> >urine.   I would have a great deal of concern about potential
> deterministic
> >radiation effects to the skin of the buttocks and genitals of this
> patient.
> >NCRP Report #111 "Developing Radiation Emergency Plans for Academic,
> Medical
> >or Industrial Facilities"  table 4.3 gives a skin contamination dose
> >equivalent  for I-131 of 1694 mSv per square centimetre per MBq per hour.
> >
> >During the first night after oral administration of the radioactivity, it
> >would not be unusual for the patient to void 10%  of the activity, which
> >would be trapped over a surface area in her diaper of about 100 cm^2.
> >Assuming the patient sleeps 8 hours with 10 mCi (370  MBq) or more of
> >excreted I-131 in her diaper (direct contact with her skin), she could
> >theoretically receive a skin dose of 50 Sv per cm^2 - which  could lead
> to
> a
> >spectrum of nasty skin effects, including erythema, moist desquamation,
> >total breakdown. The threshold dose for moist desquamation is 15 Sv.  And
> >that's just the skin dose for the first night.  The skin in that area is
> >already fragile and vulnerable to breakdown because of constant exposure
> to
> >ammonia in the urine - have you ever seen a baby with diaper rash??  Very
> >nasty and long-term effects for the patient, plus high potential for a
> >successful medical malpractice suit against the physican and medical
> >institution.
> >
> >If this were our patient, I would strongly recommend hospitalizing the
> >patient for at least 48 hours so that she could be catheterised with the
> >shielded "hot" urine collection bag emptied to the toilet every few hours
> by
> >trained nursing staff.  I would make sure the patient is very
> well-hydrated
> >(I.V. drip) and/or lots of liquid orally to flush out of her system the
> >radioactivity not taken up by the target tissue As a matter of fact, I
> have
> >done this for an incontinent patient in diapers being treated for Graves
> >disease with much less activity - when we expected only about 5 mCi
> excreted
> >via the urine.
> >
> >Regards,
> >
> >Karin
> >Gordon*******************************************************************
> **
> *
> 
> >Karin Gordon RTR, RTNM, RTT
> >Radiation Safety Coordinator
> >Winnipeg Regional Health Authority
> >Health Sciences Centre
> >GC-214, 820 Sherbrook Street
> >Winnipeg, Manitoba
> >CANADA, R3A 1R9
> >
> >phone   (204) 787-2903
> >fax        (204) 787-1313
> >e-mail    kgordon@hsc.mb.ca
> >************************************************************************
> >Message-----
> >From: Douglas Simpkin [mailto:dsimpkin@execpc.com]
> >Sent: Monday, June 19, 2000 12:37 PM
> >To: Multiple recipients of list
> >Subject: incontinent patient dosed with ~100 mCi of I-131
> >
> >Folks:
> >
> >Ignorant question time!
> >
> >Our nuclear medicine physicians are talking about treating an incontinent
> >patient with ~100 mCi of I-131. Even if we hold her (and her diapers) in
> >the hospital for a few days, she'll still be generating I-131 waste once
> >she gets home.
> >
> >How would others handling this?
> >1. Ignore waste she generates at home, and hope the landfill doesn't
> >monitor.
> >2. Have her collect her own waste for decay in her basement?
> >3. Have her collect her own waste, and we then pick up the trash for
> >decay-in-storage here. What are the DOT repercussions of me having a
> >trunk-full of hot Depends?
> >
> >Any comments?
> >Thanks,
> >Doug
> >Douglas J. Simpkin, Ph.D., D.A.B.R.
> >St. Luke's Medical Center
> >2900 West Oklahoma Avenue
> >Milwaukee, WI 53215
> >phone: (414)649-6457
> >fax: (414)649-5118
> >email: dsimpkin@execpc.com
> >
> >************************************************************************
> >The RADSAFE Frequently Asked Questions list, archives and subscription
> >information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
> >
> DAVID W. LEE, CHP
> Los Alamos National Laboratory
> Radiation Protection Services
> Radiological Engineering Team Leader
> ESH-12, MS K483
> Los Alamos, NM  87545
> PH:   (505) 667-8085
> FAX:  (505) 667-9726
> lee_david_w@lanl.gov
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
> 
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