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Tommy Knöös

Sjukhusfysiker

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Limitations of a pencil beam approach to photon dose calculations in lung tissue

Författare

  • Tommy Knöös
  • Anders Ahnesjö
  • Per Nilsson
  • Lars Weber

Summary, in English

A common limitation in treatment planning systems for photon dose calculation is to ignore the impact on electron transport and photon scatter from patient heterogeneities. The heterogeneity correlation is often based on scaling operations along beam rays as for the method according to Batho or the more novel approach of 1D convolutions along beam paths applied in pencil-beam-based systems. The effects of the limitation have been studied in a mediastinum geometry for a wide range of beam qualities by comparing the results from a pencil-beam-based treatment planning system with the results from Monte Carlo calculations. As expected, the deviations within unit-density volumes are small while deviations in low-density volumes increase with increasing beam energy from approximately 3% for 4 MV to 14% for 18 MV x-rays as a result of increased electron disequilibrium.

Avdelning/ar

  • Medicinsk strålningsfysik, Lund

Publiceringsår

1995

Språk

Engelska

Sidor

1411-1420

Publikation/Tidskrift/Serie

Physics in Medicine and Biology

Volym

40

Issue

9

Dokumenttyp

Artikel i tidskrift

Förlag

IOP Publishing

Ämne

  • Radiology, Nuclear Medicine and Medical Imaging

Status

Published

ISBN/ISSN/Övrigt

  • ISSN: 1361-6560