Re: Anti - Restenosis Therapy

["Pete Myers" <Pete.Myers@tdh.state.tx.us>]

You may be aware that there are two approaches being developed to 
irradiate arteries (primarily coronary) to prevent restenosis.  Both 
approaches are designed to deliver somewhere around 20 Gray to some 
point within the arterial wall ... exact target tissue is being 
debated.

  1. The first approach carries with it very little radiation safety
     baggage, that being an arterial stent which is coated with around
     0.5-2.0 microcuries of P-32 -- left permanently in place it de-
     livers the desired 20 Gy over a period of weeks.  Although not
     final, we're considering treating this procedure, although thera-
     peutic, in a manner similar to the way we (and NRC) are treating
     the C-14 urea pyloric ulcer breath test; staying out of the way).

  2. The second approach, in essence, utilizes a high-dose rate, remote
     control brachytherapy device (HDR/RCB; maybe 100 mCi P-32), snaked
     into the area of stenosis by a physician qualified to perform
     cardiac catheterization -- the rub here, is that physicians quali-
     fied to use radioactive material usually aren't qualified to perform
     cardiac catheterization; and vice versa.  Therefore, it looks as
     though a cardiac cath doc will use an IntraVascular Brachytherapy
     (IVB) HDR/RCB to place the source within the area of stenosis for
     about 5 minutes (whatever is necessary to deliver the desired dose).
     
     The traditional team for HDR/RCBs is also going to have to be
     involved:  Physicists for dose planning; RSO for radiation safety;
     and an Authorized Physician User of HDR/RCB to (1) evaluate potential
     patient complications which may evolve from the combination of high
     dose rate radiation and other existing patient conditions (e.g.,
     previous radiation exposures); and (2) order and supervise the use
     of the radioactive material.

I, likewise, would be interested in any experiences from the real world.

Pete.

Date:          Wed, 11 Feb 1998 13:38:05 -0600 (CST)
Reply-to:      radsafe@romulus.ehs.uiuc.edu
From:          "Dale E. Boyce" <dale@radpro.uchicago.edu>
To:            Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Subject:       Anti - Restenosis Therapy

I am interested in hearing feedback from any of you  that have
folks doings interventional treatments employing radioactive material to
irradiate coronary arteries to prevent restenosis.  Our place is
thinking about doing it, and I'd like to hear how it's going from
a radiation safety standpoint elsewhere.  Especially if there are any 
problems.

Dale Boyce
dale@radpro.uchicago.edu

Pete Myers, Cf, Med & Acad Licensing
Bureau Rad Control, Texas Dept Hlth
Phone (512) 834-6688 (FAX 834-6690)
Pete.Myers@tdh.state.tx.us