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A practical three-dimensional dosimetry system for radiation therapy.

Publication ,  Journal Article
Guo, P; Adamovics, J; Oldham, M
Published in: Med Phys
October 2006

There is a pressing need for a practical three-dimensional (3D) dosimetry system, convenient for clinical use, and with the accuracy and resolution to enable comprehensive verification of the complex dose distributions typical of modern radiation therapy. Here we introduce a dosimetry system that can achieve this challenge, consisting of a radiochromic dosimeter (PRESAGE) and a commercial optical computed tomography (CT) scanning system (OCTOPUS). PRESAGE is a transparent material with compelling properties for dosimetry, including insensitivity of the dose response to atmospheric exposure, a solid texture negating the need for an external container (reducing edge effects), and amenability to accurate optical CT scanning due to radiochromic optical contrast as opposed to light-scattering contrast. An evaluation of the performance and viability of the PRESAGE/OCTOPUS, combination for routine clinical 3D dosimetry is presented. The performance of the two components (scanner and dosimeter) was investigated separately prior to full system test. The optical CT scanner has a spatial resolution of < or = 1 mm, geometric accuracy within 1 mm, and high reconstruction linearity (with a R2 value of 0.9979 and a standard error of estimation of approximately 1%) relative to independent measurement. The overall performance of the PRESAGE/OCTOPUS system was evaluated with respect to a simple known 3D dose distribution, by comparison with GAFCHROMIC EBT film and the calculated dose from a commissioned planning system. The "measured" dose distribution in a cylindrical PRESAGE dosimeter (16 cm diameter and 11 cm height) was determined by optical-CT, using a filtered backprojection reconstruction algorithm. A three-way Gamma map comparison (4% dose difference and 4 mm distance to agreement), between the PRESAGE, EBT and calculated dose distributions, showed full agreement in measurable region of PRESAGE dosimeter (approximately 90% of radius). The EBT and PRESAGE distributions agreed more closely with each other than with the calculated plan, consistent with penumbral blurring in the planning data which was acquired with an ion chamber. In summary, our results support the conclusion that the PRESAGE optical-CT combination represents a significant step forward in 3D dosimetry, and provides a robust, clinically effective and viable high-resolution relative 3D dosimetry system for radiation therapy.

Duke Scholars

Published In

Med Phys

DOI

ISSN

0094-2405

Publication Date

October 2006

Volume

33

Issue

10

Start / End Page

3962 / 3972

Location

United States

Related Subject Headings

  • Tomography, X-Ray Computed
  • Tomography, Optical
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiotherapy
  • Radiometry
  • Phantoms, Imaging
  • Nuclear Medicine & Medical Imaging
  • Neon
  • Lasers
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Guo, P., Adamovics, J., & Oldham, M. (2006). A practical three-dimensional dosimetry system for radiation therapy. Med Phys, 33(10), 3962–3972. https://doi.org/10.1118/1.2349686
Guo, Pengyi, John Adamovics, and Mark Oldham. “A practical three-dimensional dosimetry system for radiation therapy.Med Phys 33, no. 10 (October 2006): 3962–72. https://doi.org/10.1118/1.2349686.
Guo P, Adamovics J, Oldham M. A practical three-dimensional dosimetry system for radiation therapy. Med Phys. 2006 Oct;33(10):3962–72.
Guo, Pengyi, et al. “A practical three-dimensional dosimetry system for radiation therapy.Med Phys, vol. 33, no. 10, Oct. 2006, pp. 3962–72. Pubmed, doi:10.1118/1.2349686.
Guo P, Adamovics J, Oldham M. A practical three-dimensional dosimetry system for radiation therapy. Med Phys. 2006 Oct;33(10):3962–3972.

Published In

Med Phys

DOI

ISSN

0094-2405

Publication Date

October 2006

Volume

33

Issue

10

Start / End Page

3962 / 3972

Location

United States

Related Subject Headings

  • Tomography, X-Ray Computed
  • Tomography, Optical
  • Radiotherapy Planning, Computer-Assisted
  • Radiotherapy Dosage
  • Radiotherapy
  • Radiometry
  • Phantoms, Imaging
  • Nuclear Medicine & Medical Imaging
  • Neon
  • Lasers