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How to calibrate Grenz-beams in clinical practice?

Abstract

In recent years, considerable efforts have been spent improving the precision and consistency in the whole process of calibration of high energy photon and electron beams (national protocols, primary calibration facilities ....). The reading in air of 5 different ionisation chambers (NE2532, NE2536, NE2571, PTWM23342, Markus) in an X-ray beam (RT50, HVL=0.35 mm Al) has been compared. Ali NE chambers were provided with a calibration factor Nk, the PTW chamber was directly calibrated in dose water ND,W. The polarisation and recombination effects were measured. In our reference field (ssd=4cm, field diameter 40 mm), the readings in air for the dedicated plan parallel chambers deviated by not more than 8%. The measurements with the NE2571 chamber did not correspond very well with the other measurements. For the equipment in our hospital, the dose rate in air for the reference field was measured from 1971 on and found to be very stable: 17.36 Gy/min (0.48) (1sd). An attempt was made to measure the BSF for the field defining cones used in clinical practice using a Markus plane parallel chamber, but the resulting BSF did not correspond to those reported in BJR/suppl. 17. Special attention has been be paid to the calibration of  More>>
Authors:
Schaeken, B; [1]  Bressers, E [2] 
  1. Algemeen Ziekenhius Middelheim, Antwerp (Belgium)
  2. Virga jesse Ziekenhius, Hasselt (Belgium)
Publication Date:
Dec 01, 1995
Product Type:
Conference
Report Number:
INIS-BE-0001; CONF-951246-
Reference Number:
SCA: 550603; PA: AIX-28:034226; EDB-97:069781; SN: 97001774994
Resource Relation:
Conference: 11. annual symposium of the Belgian Association of Hospital Physicists: conformal radiotherapy - physics, treatment planning and verification, Ghent (Belgium), 8-9 Dec 1995; Other Information: PBD: Dec 1995; Related Information: Is Part Of Conformal Radiotherapy: Physics, Treatment Planning and Verification. Proceedings book; De Wagter, C. [ed.]; PB: 273 p.
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; PHOTON BEAMS; CALIBRATION; RADIOTHERAPY; BEAM OPTICS; COLLIMATORS; CONFORMAL MAPPING; DELAYED RADIATION EFFECTS; DOSIMETRY; ISODOSE CURVES; NEOPLASMS; QUALITY ASSURANCE; TOMOGRAPHY
OSTI ID:
464321
Research Organizations:
Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde
Country of Origin:
Belgium
Language:
English
Other Identifying Numbers:
Other: ON: DE97622340; TRN: BE9700025034226
Availability:
INIS; OSTI as DE97622340
Submitting Site:
BEN
Size:
pp. 12
Announcement Date:

Citation Formats

Schaeken, B, and Bressers, E. How to calibrate Grenz-beams in clinical practice?. Belgium: N. p., 1995. Web.
Schaeken, B, & Bressers, E. How to calibrate Grenz-beams in clinical practice?. Belgium.
Schaeken, B, and Bressers, E. 1995. "How to calibrate Grenz-beams in clinical practice?" Belgium.
@misc{etde_464321,
title = {How to calibrate Grenz-beams in clinical practice?}
author = {Schaeken, B, and Bressers, E}
abstractNote = {In recent years, considerable efforts have been spent improving the precision and consistency in the whole process of calibration of high energy photon and electron beams (national protocols, primary calibration facilities ....). The reading in air of 5 different ionisation chambers (NE2532, NE2536, NE2571, PTWM23342, Markus) in an X-ray beam (RT50, HVL=0.35 mm Al) has been compared. Ali NE chambers were provided with a calibration factor Nk, the PTW chamber was directly calibrated in dose water ND,W. The polarisation and recombination effects were measured. In our reference field (ssd=4cm, field diameter 40 mm), the readings in air for the dedicated plan parallel chambers deviated by not more than 8%. The measurements with the NE2571 chamber did not correspond very well with the other measurements. For the equipment in our hospital, the dose rate in air for the reference field was measured from 1971 on and found to be very stable: 17.36 Gy/min (0.48) (1sd). An attempt was made to measure the BSF for the field defining cones used in clinical practice using a Markus plane parallel chamber, but the resulting BSF did not correspond to those reported in BJR/suppl. 17. Special attention has been be paid to the calibration of beams with field size comparable to the dimension of the chamber window- chamber body.}
place = {Belgium}
year = {1995}
month = {Dec}
}