open access

Vol 9, No 6 (2004)
Published online: 2004-01-01
Submitted: 2004-04-30
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Experimental evaluation of ALFARD treatment planning system for 6 MV photon irradiation: a lung case study

Asghar Mesbahi, Mahmoud Allahverdi, Hossein Gheraati, Ehsan Mohammadi
DOI: 10.1016/S1507-1367(04)71030-5
·
Rep Pract Oncol Radiother 2004;9(6):217-221.

open access

Vol 9, No 6 (2004)
Published online: 2004-01-01
Submitted: 2004-04-30

Abstract

Purpose

Simple inhomogeneity correction methods available in a number of currently applied treatment planning systems are not accurate enough for dose calculations in lung irradiations. The purpose of this study was to evaluate the accuracy of the ALFARD treatment planning system in dose calculations for lung irradiation.

Material and methods

An anatomic thorax phantom and a 6 MV photon beam were used for our irradiation. Our set-up consisted of an an-terior single field for the left lung of a thorax phantom with field sizes of 5 × 5 cm2 and 10×10 cm2. The percentage depth doses for each point in the lung were measured by a Pinpoint ionization chamber and calculated by the ALFARD treatment planning system. The results of calculations and measurements were compared.

Results

The ALFARD calculations overestimated measurements at all points and field sizes. The magnitude of error increased with depth of the calculation point from 2.7% to 17.3% for the field size of 5 × 5 cm2. The error for 5 × 5 cm2 was approximately twice as high as that for10×10 cm2.

Conclusions

The ALFARD treatment planning system cannot calculate the dose in the lung accurately. This may be due to inherent deficiencies of the effective path length method, which is implemented in the ALFARD treatment planning system.

Abstract

Purpose

Simple inhomogeneity correction methods available in a number of currently applied treatment planning systems are not accurate enough for dose calculations in lung irradiations. The purpose of this study was to evaluate the accuracy of the ALFARD treatment planning system in dose calculations for lung irradiation.

Material and methods

An anatomic thorax phantom and a 6 MV photon beam were used for our irradiation. Our set-up consisted of an an-terior single field for the left lung of a thorax phantom with field sizes of 5 × 5 cm2 and 10×10 cm2. The percentage depth doses for each point in the lung were measured by a Pinpoint ionization chamber and calculated by the ALFARD treatment planning system. The results of calculations and measurements were compared.

Results

The ALFARD calculations overestimated measurements at all points and field sizes. The magnitude of error increased with depth of the calculation point from 2.7% to 17.3% for the field size of 5 × 5 cm2. The error for 5 × 5 cm2 was approximately twice as high as that for10×10 cm2.

Conclusions

The ALFARD treatment planning system cannot calculate the dose in the lung accurately. This may be due to inherent deficiencies of the effective path length method, which is implemented in the ALFARD treatment planning system.

Get Citation

Keywords

treatment planning systems; ALFARD; effective path length method; lung irradiation; accuracy

About this article
Title

Experimental evaluation of ALFARD treatment planning system for 6 MV photon irradiation: a lung case study

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 9, No 6 (2004)

Pages

217-221

Published online

2004-01-01

DOI

10.1016/S1507-1367(04)71030-5

Bibliographic record

Rep Pract Oncol Radiother 2004;9(6):217-221.

Keywords

treatment planning systems
ALFARD
effective path length method
lung irradiation
accuracy

Authors

Asghar Mesbahi
Mahmoud Allahverdi
Hossein Gheraati
Ehsan Mohammadi

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