Dosimetric Consequences of Intrafraction Prostate Motion

Haisen S. Li, Indrin J. Chetty, Charles Arthur Enke, Ryan D. Foster, Twyla R. Willoughby, Patrick A. Kupellian, Timothy D. Solberg

Research output: Contribution to journalArticle

86 Citations (Scopus)

Abstract

Purpose: To analyze characteristics of intrafraction prostate motion, monitored using the Calypso system, and investigate dosimetric consequences of the motion for different clinical target volume (CTV) to planning target volume (PTV) margins. Methods and Materials: Motion characteristics were analyzed for 1,267 tracking sessions and 35 patients. Using prostate-PTV margins of 0, 1, 2, 3, and 5 mm, dose metrics for the prostate gland, bladder, and rectum were evaluated for scenarios including patient population, individual patients showing the greatest motion during the course of treatment, and the individual session with the largest overall movement. Composite dose distributions incorporating motion blurring were calculated by convolving static intensity-modulated radiotherapy plans with corresponding motion probability functions. Results: For prostate-PTV margins of 2 mm or greater, intrafraction motion did not compromise prostate dose coverage for either the patient population or individual patients. For the patient showing the largest overall movement, the prostate equivalent uniform dose was reduced by only 17.4 cGy (0.23%), and the minimum prostate dose remained greater than 95% of the nominal dose. For margins less than 2 mm, the prostate dose-volume histogram in the same patient was slightly compromised, and the equivalent uniform dose was reduced by 38.5 cGy (0.51%). Sparing of the bladder and rectum was improved substantially by reducing margins. Conclusions: Although significant motion can be observed during individual fractions, the dosimetric consequences are insignificant during a typical course of radiotherapy (30-40 fractions) with CTV-PTV margins of 2 mm or greater provided that the Calypso system is applied for pretreatment localization. Further reduction of the margin is possible if intrafraction realignment is performed.

Original languageEnglish (US)
Pages (from-to)801-812
Number of pages12
JournalInternational Journal of Radiation Oncology Biology Physics
Volume71
Issue number3
DOIs
StatePublished - Jul 1 2008

Fingerprint

Prostate
margins
dosage
planning
Calypso
rectum
Rectum
bladder
Urinary Bladder
radiation therapy
Intensity-Modulated Radiotherapy
prostate gland
blurring
Population
Radiotherapy
histograms
pretreatment
composite materials

Keywords

  • Calypso system
  • Dose blurring
  • Intrafraction prostate motion
  • Prostate-to-PTV margin
  • Real-time tracking

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

Cite this

Li, H. S., Chetty, I. J., Enke, C. A., Foster, R. D., Willoughby, T. R., Kupellian, P. A., & Solberg, T. D. (2008). Dosimetric Consequences of Intrafraction Prostate Motion. International Journal of Radiation Oncology Biology Physics, 71(3), 801-812. https://doi.org/10.1016/j.ijrobp.2007.10.049

Dosimetric Consequences of Intrafraction Prostate Motion. / Li, Haisen S.; Chetty, Indrin J.; Enke, Charles Arthur; Foster, Ryan D.; Willoughby, Twyla R.; Kupellian, Patrick A.; Solberg, Timothy D.

In: International Journal of Radiation Oncology Biology Physics, Vol. 71, No. 3, 01.07.2008, p. 801-812.

Research output: Contribution to journalArticle

Li, HS, Chetty, IJ, Enke, CA, Foster, RD, Willoughby, TR, Kupellian, PA & Solberg, TD 2008, 'Dosimetric Consequences of Intrafraction Prostate Motion', International Journal of Radiation Oncology Biology Physics, vol. 71, no. 3, pp. 801-812. https://doi.org/10.1016/j.ijrobp.2007.10.049
Li, Haisen S. ; Chetty, Indrin J. ; Enke, Charles Arthur ; Foster, Ryan D. ; Willoughby, Twyla R. ; Kupellian, Patrick A. ; Solberg, Timothy D. / Dosimetric Consequences of Intrafraction Prostate Motion. In: International Journal of Radiation Oncology Biology Physics. 2008 ; Vol. 71, No. 3. pp. 801-812.
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