Impact of setup uncertainty in the dosimetry of prostate and surrounding tissues in prostate cancer patients treated with Peacock/IMRT

Salahuddin Ahmad, Maria T. Vlachaki, Terrance N. Teslow, Chad M. Amosson, John McGary, Bin S. Teh, Shiao Y. Woo, Edward Brian Butler, Walter H. Grant

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

The purpose of this paper was to assess the effect of setup uncertainty on dosimetry of prostate, seminal vesicles, bladder, rectum, and colon in prostate cancer patients treated with Peacock intensity-modulated radiation therapy (IMRT). Ten patients underwent computed tomography (CT) scans using the "prostate box" for external, and an "endorectal balloon" for target immobilization devices, and treatment plans were generated (T1). A maximum of ± 5-mm setup error was chosen to model dosimetric effects. Isodose lines from the T1 treatment plan were then superimposed on each patient's CT anatomy shifted by 5 mm toward the cephalad and caudal direction, generating 2 more dosimetric plans (H1 and H2, respectively). Average mean doses ranged from 74.5 to 74.92 Gy for prostate and 73.65 to 74.94 Gy for seminal vesicles. Average percent target volume below 70 Gy increased significantly for seminal vesicles, from 0.53% to 6.26%, but minimally for prostate, from 2.08% to 4.4%. Dose statistics adhered to prescription limits for normal tissues. Setup uncertainty had minimum impact on target dose escalation and normal tissue dosing. The impact of target dose inhomogeneity is currently evaluated in clinical studies.

Original languageEnglish (US)
Pages (from-to)1-7
Number of pages7
JournalMedical Dosimetry
Volume30
Issue number1
DOIs
StatePublished - 2005

Keywords

  • IMRT
  • Prostate cancer
  • Setup error

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Health Professions(all)
  • Radiation

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