3D-segmentation of the 18F-choline PET signal for target volume definition in radiation therapy of the prostate.

Full Abstract

Volumetric assessment of PET signals becomes increasingly relevant for radiotherapy (RT) planning. Here, we investigate the utility of 18F-choline PET signals to serve as a structure for semi-automatic segmentation for forward treatment planning of prostate cancer. 18F-choline PET and CT scans of ten patients with histologically proven prostate cancer without extracapsular growth were acquired using a combined PET/CT scanner. Target volumes were manually delineated on CT images using standard software. Volumes were also obtained from 18F-choline PET images using an asymmetrical segmentation algorithm. PTVs were derived from CT 18F-choline PET based clinical target volumes (CTVs) by automatic expansion and comparative planning was performed. As a read-out for dose given to non-target structures, dose to the rectal wall was assessed. Planning target volumes (PTVs) derived from CT and 18F-choline PET yielded comparable results. Optimal matching of CT and 18F-choline PET derived volumes in the lateral and cranial-caudal directions was obtained using a background-subtracted signal thresholds of 23.0+/-2.6%. In antero-posterior direction, where adaptation compensating for rectal signal overflow was required, optimal matching was achieved with a threshold of 49.5+/-4.6%. 3D-conformal planning with CT or 18F-choline PET resulted in comparable doses to the rectal wall. Choline PET signals of the prostate provide adequate spatial information amendable to standardized asymmetrical region growing algorithms for PET-based target volume definition for external beam RT.

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Author information

Author/s: Ciernik, I Frank (IF); Brown, Derek W (DW); Schmid, Daniel (D); Hany, Thomas (T); Egli, Peter (P); Davis, J Bernard (JB);

Affiliation: Center for Clinical Research, Zurich University Hospital, Zurich, Switzerland. ciernik(-atsign-)iosi.ch

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Technology in cancer research & treatment (Technol Cancer Res Treat), published in United States. (Language: eng)

Reference: 2007-Feb; vol 6 (issue 1) : pp 23-30

Dates: Created 2007/01/23; Completed 2007/05/21;

PMID: 17241097, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Choline - analogs & derivatives; diagnostic use
Humans
Imaging, Three-Dimensional
Male

Positron-Emission Tomography
Prostate - radionuclide imaging
Prostatic Neoplasms - radionuclide imaging; radiotherapy
Radiotherapy Planning, Computer-Assisted - methods

Associated Chemicals: fluoromethylcholine (0) ; Choline (62-49-7)

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