NCCHPS 27 March Meeting

["Jack H. Elliott" <elliottj@pacbell.net>]

****** March 27th Dinner Meeting *******
     
     The NCCHPS is pleased to announce its March 1997 dinner meeting.  
     Arthur L. Boyer, Ph.D. of the Stanford University Department of 
     Radiation Oncology will offer a presentation entitled 
     "Heath Physics Implications of Intensity Modulated Radiotherapy."
     
     Please join us for an evening of dinner and professional enrichment 
     at Spenger's Fish Grotto in Berkeley.
     
     Date:      Thursday, March 27, 1997
     
     Directions: Take I-80 to University Avenue heading East.  Spenger's 
     is   at 919 4th Street, Berkeley, north of the overpass. Ample
on-site free
     parking

          Schedule:  6:00 - Cocktails (no host bar)
                7:00 - Dinner
                8:00 - Presentation by Dr. Boyer
    
     Menu:      Please indicate your meal choice when responding:
    
                A      Roast Beef
                B      Fillet of sole or snapper
                C      Seafood fettuccine

     Price of the meal including sales tax and service charge is $19.00. 
     Reservations (mailed, phoned or e-mailed) must be made with the 
     Treasurer Radoslav Radev 48 hours prior to the meeting.
           Mailto:rado@uclink2.berkeley.edu

     ** PREVIEW OF DR. BOYER'S PRESENTATION **
   
The purpose of the work that Dr. Boyer will describe is to estimate
the dose delivered to patients by photons and neutrons outside the 
radiation fields when beam intensity modulated conformal radiotherapy 
(IMCRT) is given. These estimates are then used to compute the risk of 
induction of secondary cancers as a result of the radiation therapy.
 
The x-ray and neutron leakage accompanying two beam-intensity 
modulation techniques deliverable by currently available linear 
accelerators were estimated for 6 MV, 18 MV, and 25 MV x-ray energies. 
Estimates of whole-body dose equivalents were determined using
leakage measurements reported in the literature and treatment 
parameters derived for two modulated beam-intensity conformal therapy 
techniques.  Risk values recommended by the  NCRP were used to 
estimate the resulting risk of fatal radiation-induced cancer for7000
cGy
prescribed tumor doses. The computed  worst-case risks of 
secondary cancers increased in the range from 0.8% for 6-MV x-rays to
19.5% for 25-MV x-rays.  The investigators conclude that careful 
consideration should be made of the implications associated with 
secondary whole body radiation before implementation of beam intensity
modulated conformal therapy using x-ray energies greater than 10 MV.
-- 
Jack H. Elliott