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Image guided RT allow reduced margins & low collateraldamage

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Reduction of dose delivered to organs at risk in prostate cancer patients via image-guided radiation therapy - Abstract Show Comments PDF Print E-mail


Wednesday, 06 January 2010

Vanderbilt-Ingram Cancer Center, Department of Radiation Oncology, Vanderbilt University School of Medicine, Nashville, Tennessee; Department of Physics and Astronomy, Vanderbilt University College of Art and Sciences, B-902, TVC, 1301 Medical Center Drive, Nashville, Tennessee.

To determine whether image guidance can improve the dose delivered to target organs and organs at risk (OARs) for prostate cancer patients treated with intensity-modulated radiotherapy (IMRT).

Eight prostate cancer patients were treated with IMRT to 76 Gy at 2 Gy per fraction. Daily target localization was performed via alignment of three intraprostatic fiducials and weekly kV-cone beam computed tomography (CBCT) scans. The prostate and OARs were manually contoured on each CBCT by a single physician. Daily patient setup shifts were obtained by comparing alignment of skin tattoos with the treatment position based on fiducials. Treatment fields were retrospectively applied to CBCT scans. The dose distributions were calculated using actual treatment plans (an 8-mm PTV margin everywhere except for 6-mm posteriorly) with and without image guidance shifts. Furthermore, the feasibility of margin reduction was evaluated by reducing planning margins to 4 mm everywhere except for 3 mm posteriorly.

For the eight treatment plans on the 56 CBCT scans, the average doses to 98% of the prostate (D98) were 102% (range, 99-104%) and 99% (range, 45-104%) with and without image guidance, respectively. Using margin reduction, the average D98s were 100% (range, 84-104%) and 92% (range, 40-104%) with and without image guidance, respectively.

Currently, margins used in IMRT plans are adequate to deliver a dose to the prostate with conventional patient positioning using skin tattoos or bony anatomy. The use of image guidance may facilitate significant reduction of planning margins. Future studies to assess the efficacy of decreasing margins and improvement of treatment-related toxicities are warranted.

Written by:

Pawlowski JM, Yang ES, Malcolm AW, Coffey CW, Ding GX. Are you the author?


Int J Radiat Oncol Biol Phys.. Epub ahead of print.


PubMed Abstract

PMID:20004528 Forum: Other prostate cancer topics including radiation Title: Image guided RT may allow reduced margins and lower collateral damage.

This extract can be found on http://PubMed.com, and is in the public domain.

On PubMed.com there will be a link to the full paper (often $30, sometimes free).

Any highlighting (except the title) is not by the author, but by Jim Marshall.

Jim is not a doctor.

This page was found on the Advanced Prostate Cancer Community for Australian men at http://advancedprost...lia.ipbhost.com.

The link is hard to remember.

An easier way to find it is to go to JimJimJimJim.com and click on Prostate.

That's the word Jim four times, no spaces, followed by .com.

If you need other help - to perhaps find someone to talk to or a local support group:

Click on the Contact Jim button at http://JimJimJimJim.com.

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