Use of cone-beam imaging to correct for catheter displacement in high dose-rate prostate brachytherapy
| Autor: | D. Andrew Loblaw, Raxa Sankreacha, Gerard Morton, Rick Holly, Thomas Cisecki, Niki Law, Hans T. Chung |
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| Rok vydání: | 2010 |
| Předmět: |
Male
Cone beam computed tomography medicine.medical_specialty Catheters medicine.medical_treatment Brachytherapy Fiducial Markers Medicine Dosimetry Humans Radiology Nuclear Medicine and imaging Displacement (orthopedic surgery) business.industry Radiotherapy Planning Computer-Assisted Prostatic Neoplasms Reproducibility of Results Radiotherapy Dosage Cone-Beam Computed Tomography High-Dose Rate Brachytherapy Catheter Treatment Outcome Oncology Radiology Fiducial marker business Nuclear medicine Prostate brachytherapy Follow-Up Studies |
| Zdroj: | Brachytherapy. 10(4) |
| ISSN: | 1873-1449 |
| Popis: | To determine the magnitude of catheter displacement between time of planning and time of treatment delivery for patients undergoing high dose-rate (HDR) brachytherapy, the dosimetric impact of catheter displacement, and the ability to improve dosimetry by catheter readjustment.Twenty consecutive patients receiving single fraction HDR brachytherapy underwent kilovoltage cone-beam CT in the treatment room before treatment. If catheter displacement was apparent, catheters were adjusted and imaging repeated. Both sets of kilovoltage cone-beam CT image sets were coregistered off-line with the CT data set used for planning with rigid fusion of anatomy based on implanted fiducials. Catheter displacement was measured on both sets of images and dosimetry calculated.Mean internal displacement of catheters was 11mm. This would have resulted in a decrease in mean volume receiving 100% of prescription dose (V(100)) from the planned 97.6% to 77.3% (p0.001), a decrease of the mean dose to 90% of the prostate (D(90)) from 110.5% to 72.9% (p0.001), and increase in dose to 10% of urethra (urethra D(10)) from 118% to 125% (p=0.0094). Each 1cm of catheter displacement resulted in a 20% decrease in V(100) and 36% decrease in D(90). Catheter readjustment resulted in a final treated mean V(100) of 90.2% and D(90) of 97.4%, both less than planned. Mean urethra D(10) remained higher at126% (p=0.0324).Significantly, internal displacement of HDR catheters commonly occurs between time of CT planning and treatment delivery, even when only a single fraction is used. The adverse effects on dosimetry can be partly corrected by readjustment of catheter position. |
| Databáze: | OpenAIRE |
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