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An investigation of a PRESAGE® in vivo dosimeter for brachytherapy.

Publication ,  Journal Article
Vidovic, AK; Juang, T; Meltsner, S; Adamovics, J; Chino, J; Steffey, B; Craciunescu, O; Oldham, M
Published in: Phys Med Biol
July 21, 2014

Determining accurate in vivo dosimetry in brachytherapy treatment with high dose gradients is challenging. Here we introduce, investigate, and characterize a novel in vivo dosimeter and readout technique with the potential to address this problem. A cylindrical (4 mm × 20 mm) tissue equivalent radiochromic dosimeter PRESAGE® in vivo (PRESAGE®-IV) is investigated. Two readout methods of the radiation induced change in optical density (OD) were investigated: (i) volume-averaged readout by spectrophotometer, and (ii) a line profile readout by 2D projection imaging utilizing a high-resolution (50 micron) telecentric optical system. Method (i) is considered the gold standard when applied to PRESAGE® in optical cuvettes. The feasibility of both methods was evaluated by comparison to standard measurements on PRESAGE® in optical cuvettes via spectrophotometer. An end-to-end feasibility study was performed by a side-by-side comparison with TLDs in an (192)Ir HDR delivery. 7 and 8 Gy was delivered to PRESAGE®-IV and TLDs attached to the surface of a vaginal cylinder. Known geometry enabled direct comparison of measured dose with a commissioned treatment planning system. A high-resolution readout study under a steep dose gradient region showed 98.9% (5%/1 mm) agreement between PRESAGE®-IV and Gafchromic® EBT2 Film. Spectrometer measurements exhibited a linear dose response between 0-15 Gy with sensitivity of 0.0133 ± 0.0007 ΔOD/(Gy ⋅ cm) at the 95% confidence interval. Method (ii) yielded a linear response with sensitivity of 0.0132 ± 0.0006 (ΔOD/Gy), within 2% of method (i). Method (i) has poor spatial resolution due to volume averaging. Method (ii) has higher resolution (∼1 mm) without loss of sensitivity or increased noise. Both readout methods are shown to be feasible. The end-to-end comparison revealed a 2.5% agreement between PRESAGE®-IV and treatment plan in regions of uniform high dose. PRESAGE®-IV shows promise for in vivo dose verification, although improved sensitivity would be desirable. Advantages include high-resolution, convenience and fast, low-cost readout.

Duke Scholars

Published In

Phys Med Biol

DOI

EISSN

1361-6560

Publication Date

July 21, 2014

Volume

59

Issue

14

Start / End Page

3893 / 3905

Location

England

Related Subject Headings

  • Tomography, X-Ray Computed
  • Radiometry
  • Nuclear Medicine & Medical Imaging
  • Iridium Radioisotopes
  • Humans
  • Feasibility Studies
  • Brachytherapy
  • 5105 Medical and biological physics
  • 1103 Clinical Sciences
  • 0903 Biomedical Engineering
 

Citation

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Vidovic, A. K., Juang, T., Meltsner, S., Adamovics, J., Chino, J., Steffey, B., … Oldham, M. (2014). An investigation of a PRESAGE® in vivo dosimeter for brachytherapy. Phys Med Biol, 59(14), 3893–3905. https://doi.org/10.1088/0031-9155/59/14/3893
Vidovic, A. K., T. Juang, S. Meltsner, J. Adamovics, J. Chino, B. Steffey, O. Craciunescu, and M. Oldham. “An investigation of a PRESAGE® in vivo dosimeter for brachytherapy.Phys Med Biol 59, no. 14 (July 21, 2014): 3893–3905. https://doi.org/10.1088/0031-9155/59/14/3893.
Vidovic AK, Juang T, Meltsner S, Adamovics J, Chino J, Steffey B, et al. An investigation of a PRESAGE® in vivo dosimeter for brachytherapy. Phys Med Biol. 2014 Jul 21;59(14):3893–905.
Vidovic, A. K., et al. “An investigation of a PRESAGE® in vivo dosimeter for brachytherapy.Phys Med Biol, vol. 59, no. 14, July 2014, pp. 3893–905. Pubmed, doi:10.1088/0031-9155/59/14/3893.
Vidovic AK, Juang T, Meltsner S, Adamovics J, Chino J, Steffey B, Craciunescu O, Oldham M. An investigation of a PRESAGE® in vivo dosimeter for brachytherapy. Phys Med Biol. 2014 Jul 21;59(14):3893–3905.
Journal cover image

Published In

Phys Med Biol

DOI

EISSN

1361-6560

Publication Date

July 21, 2014

Volume

59

Issue

14

Start / End Page

3893 / 3905

Location

England

Related Subject Headings

  • Tomography, X-Ray Computed
  • Radiometry
  • Nuclear Medicine & Medical Imaging
  • Iridium Radioisotopes
  • Humans
  • Feasibility Studies
  • Brachytherapy
  • 5105 Medical and biological physics
  • 1103 Clinical Sciences
  • 0903 Biomedical Engineering