open access

Vol 15, No 6 (2010)
Published online: 2010-11-01
Submitted: 2010-07-06
Get Citation

Air kerma strength characterization of a GZP6 Cobalt-60 brachytherapy source

Mohammad Taghi Toossi, Mahdi Ghorbani, Ali Asghar Mowlavi, Mojtaba Taheri, Mohsen Layegh, Yasha Makhdoumi, Ali Soleimani Meigooni
DOI: 10.1016/j.rpor.2010.10.002
·
Rep Pract Oncol Radiother 2010;15(6):190-194.

open access

Vol 15, No 6 (2010)
Published online: 2010-11-01
Submitted: 2010-07-06

Abstract

Background

Task group number 40 (TG-40) of the American Association of Physicists in Medicine (AAPM) has recommended calibration of any brachytherapy source before its clinical use. GZP6 afterloading brachytherapy unit is a 60Co high dose rate (HDR) system recently being used in some of the Iranian radiotherapy centers.

Aim

In this study air kerma strength (AKS) of 60Co source number three of this unit was estimated by Monte Carlo simulation and in air measurements.

Materials and methods

Simulation was performed by employing the MCNP-4C Monte Carlo code. Self-absorption of the source core and its capsule were taken into account when calculating air kerma strength. In-air measurements were performed according to the multiple distance method; where a specially designed jig and a 0.6[[ce:hsp sp="0.25"/]]cm3 Farmer type ionization chamber were used for the measurements. Monte Carlo simulation, in air measurement and GZP6 treatment planning results were compared for primary air kerma strength (as for November 8th 2005).

Results

Monte Carlo calculated and in air measured air kerma strength were respectively equal to 17240.01[[ce:hsp sp="0.25"/]]μGym2[[ce:hsp sp="0.25"/]]h−1 and 16991.83[[ce:hsp sp="0.25"/]]μGym2[[ce:hsp sp="0.25"/]]h−1. The value provided by the GZP6 treatment planning system (TPS) was “15355[[ce:hsp sp="0.25"/]]μGym2[[ce:hsp sp="0.25"/]]h−1”.

Conclusion

The calculated and measured AKS values are in good agreement. Calculated-TPS and measured-TPS AKS values are also in agreement within the uncertainties related to our calculation, measurements and those certified by the GZP6 manufacturer. Considering the uncertainties, the TPS value for AKS is validated by our calculations and measurements, however, it is incorporated with a large uncertainty.

Abstract

Background

Task group number 40 (TG-40) of the American Association of Physicists in Medicine (AAPM) has recommended calibration of any brachytherapy source before its clinical use. GZP6 afterloading brachytherapy unit is a 60Co high dose rate (HDR) system recently being used in some of the Iranian radiotherapy centers.

Aim

In this study air kerma strength (AKS) of 60Co source number three of this unit was estimated by Monte Carlo simulation and in air measurements.

Materials and methods

Simulation was performed by employing the MCNP-4C Monte Carlo code. Self-absorption of the source core and its capsule were taken into account when calculating air kerma strength. In-air measurements were performed according to the multiple distance method; where a specially designed jig and a 0.6[[ce:hsp sp="0.25"/]]cm3 Farmer type ionization chamber were used for the measurements. Monte Carlo simulation, in air measurement and GZP6 treatment planning results were compared for primary air kerma strength (as for November 8th 2005).

Results

Monte Carlo calculated and in air measured air kerma strength were respectively equal to 17240.01[[ce:hsp sp="0.25"/]]μGym2[[ce:hsp sp="0.25"/]]h−1 and 16991.83[[ce:hsp sp="0.25"/]]μGym2[[ce:hsp sp="0.25"/]]h−1. The value provided by the GZP6 treatment planning system (TPS) was “15355[[ce:hsp sp="0.25"/]]μGym2[[ce:hsp sp="0.25"/]]h−1”.

Conclusion

The calculated and measured AKS values are in good agreement. Calculated-TPS and measured-TPS AKS values are also in agreement within the uncertainties related to our calculation, measurements and those certified by the GZP6 manufacturer. Considering the uncertainties, the TPS value for AKS is validated by our calculations and measurements, however, it is incorporated with a large uncertainty.

Get Citation

Keywords

GZP6 HDR system; Air kerma strength; MCNP 4C Monte Carlo code; In air measurement

About this article
Title

Air kerma strength characterization of a GZP6 Cobalt-60 brachytherapy source

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 15, No 6 (2010)

Pages

190-194

Published online

2010-11-01

DOI

10.1016/j.rpor.2010.10.002

Bibliographic record

Rep Pract Oncol Radiother 2010;15(6):190-194.

Keywords

GZP6 HDR system
Air kerma strength
MCNP 4C Monte Carlo code
In air measurement

Authors

Mohammad Taghi Toossi
Mahdi Ghorbani
Ali Asghar Mowlavi
Mojtaba Taheri
Mohsen Layegh
Yasha Makhdoumi
Ali Soleimani Meigooni

Important: This website uses cookies. More >>

The cookies allow us to identify your computer and find out details about your last visit. They remembering whether you've visited the site before, so that you remain logged in - or to help us work out how many new website visitors we get each month. Most internet browsers accept cookies automatically, but you can change the settings of your browser to erase cookies or prevent automatic acceptance if you prefer.

By "Via Medica sp. z o.o." sp.k., ul. Świętokrzyska 73, 80–180 Gdańsk, Poland
tel.:+48 58 320 94 94, fax:+48 58 320 94 60, e-mail: journals@viamedica.pl