Gold marker displacement due to needle insertion during HDR-brachytherapy for treatment of prostate cancer: a prospective cone beam computed tomography and kilovoltage on-board imaging (kV-OBI) study
- PMID: 22348595
- PMCID: PMC3307434
- DOI: 10.1186/1748-717X-7-24
Gold marker displacement due to needle insertion during HDR-brachytherapy for treatment of prostate cancer: a prospective cone beam computed tomography and kilovoltage on-board imaging (kV-OBI) study
Abstract
Purpose: To evaluate gold marker displacement due to needle insertion during HDR-brachytherapy for therapy of prostate cancer.
Patients and methods: 18 patients entered into this prospective evaluation. Three gold markers were implanted into the prostate during the first HDR-brachytherapy procedure after the irradiation was administered. Three days after marker implantation all patients had a CT-scan for planning purpose of the percutaneous irradiation. Marker localization was defined on the digitally-reconstructed-radiographs (DRR) for daily (VMAT technique) or weekly (IMRT) set-up error correction. Percutaneous therapy started one week after first HDR-brachytherapy. After the second HDR-brachytherapy, two weeks after first HDR-brachtherapy, a cone-beam CT-scan was done to evaluate marker displacement due to needle insertion. In case of marker displacement, the actual positions of the gold markers were adjusted on the DRR.
Results: The value of the gold marker displacement due to the second HDR-brachytherapy was analyzed in all patients and for each gold marker by comparison of the marker positions in the prostate after soft tissue registration of the prostate of the CT-scans prior the first and second HDR-brachytherapy. The maximum deviation was 5 mm, 7 mm and 12 mm for the anterior-posterior, lateral and superior-inferior direction. At least one marker in each patient showed a significant displacement and therefore new marker positions were adjusted on the DRRs for the ongoing percutaneous therapy.
Conclusions: Needle insertion in the prostate due to HDR-brachytherapy can lead to gold marker displacements. Therefore, it is necessary to verify the actual position of markers after the second HDR-brachytherapy. In case of significant deviations, a new DRR with the adjusted marker positions should be generated for precise positioning during the ongoing percutaneous irradiation.
References
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- Schiffner DC, Gottschalk AR, Lometti M, Aubin M, Pouliot J, Speight J. et al.Daily electronic portal imaging of implanted gold seed fiducials in patients undergoing radiotherapy after radical prostatectomy. Int J Radiat Oncol Biol Phys. 2007;67:610–619. doi: 10.1016/j.ijrobp.2006.09.042. - DOI - PubMed
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