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Title: Absolute dose measurements by means of a small cylindrical ionization chamber for very high dose per pulse high energy electron beams

Very high dose per pulse (3-13 cGy/pulse) high energy electron beams are currently produced by special linear accelerators (linac) dedicated to Intra Operative Radiation Therapy (IORT). The electron beams produced by such linacs are collimated by special Perspex applicators of various size and cylindrically shaped. The biggest problems from the dosimetric point of view are caused by the high dose-per-pulse values and the use of inclined applicators. In this work measurements of absolute dose for the inclined applicators were done by using a small cylindrical ionization chamber, type CC01 (Wellhofer), a parallel plane ionization chamber type Markus (PTW 23343) and radiochromic films type EBT. We show a method which allows calculating the quality correction factors for CC01 chamber with an uncertainty of 1% and the absolute dose value for the inclined applicators using CC01 with an uncertainty of 3.1% for electron beams of energy of 6 and 7 MeV produced by the linac dedicated to IORT Novac7.
Authors:
; ;  [1]
  1. U.O. Fisica Sanitaria, Azienda Ospedaliero-Universitaria Pisana, via Roma 67, 56126 Pisa (Italy)
Publication Date:
OSTI Identifier:
20951108
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 34; Journal Issue: 3; Other Information: DOI: 10.1118/1.2436979; (c) 2007 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; CORRECTIONS; DOSIMETRY; ELECTRON BEAMS; IONIZATION CHAMBERS; LINEAR ACCELERATORS; PERSPEX; RADIATION DOSES; RADIOTHERAPY