The effect of catheter displacement and anatomical variations on the dose distribution in MRI-guided focal HDR brachytherapy for prostate cancer
| Autor: | Maurice A.A.J. van den Bosch, Jochem R.N. van der Voort van Zyp, Marinus A. Moerland, Max Peters, M Maenhout, Marco van Vulpen, Maxence Borot de Battisti |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Organs at Risk
Male medicine.medical_treatment Radiotherapy Planning Brachytherapy 030218 nuclear medicine & medical imaging Prostate cancer Computer-Assisted 0302 clinical medicine Foreign-Body Migration Prostate Catheter displacement Prospective Studies Radiation treatment planning Ultrasonography medicine.diagnostic_test Ultrasound Radiotherapy Dosage Organs at Risk/anatomy & histology Magnetic Resonance Imaging Catheter medicine.anatomical_structure Oncology Radiology Nuclear Medicine and imaging 030220 oncology & carcinogenesis Prostatic Neoplasms/diagnostic imaging Radiology High-dose-rate medicine.medical_specialty Catheters 03 medical and health sciences medicine Journal Article Humans Radiology Nuclear Medicine and imaging Displacement (orthopedic surgery) Aged business.industry Radiotherapy Planning Computer-Assisted Foreign-Body Migration/diagnostic imaging Prostatic Neoplasms Magnetic resonance imaging Prostate/diagnostic imaging medicine.disease MRI guided Brachytherapy/methods business |
| Zdroj: | Brachytherapy, 17(1), 68. Elsevier Inc. |
| ISSN: | 1538-4721 |
| Popis: | Purpose The aim of this study was to analyze the effect of catheter displacement and anatomical variations of prostate and organs at risk on dose distribution in MRI-guided 19 Gy single fraction focal high-dose-rate brachytherapy (HDR-BT) of the prostate. Methods and Materials Seventeen patients with localized prostate cancer were enrolled in a prospective trial investigating focal HDR-BT in a 1.5 T MRI-HDR-BT facility. The diagnostic MRI delineations were registered with intraoperative MR scan, and a single fraction of 19 Gy was applied to the visible tumor. Self-anchoring umbrella catheters were used for HDR-BT delivery. A 1.5 T MRI was performed directly after ultrasound (US)-guided catheter placement for treatment planning. After treatment and before removal of catheters, a posttreatment 1.5 T MRI was performed. Regions of interest were also delineated on the posttreatment MR images and the catheters of 17 patients were reconstructed. The dose plan was constructed for the posttreatment MRI scan to assess the influence of catheter migration and anatomical variation on the dose delivered to the target and the organs at risk. Also on the posttreatment MRI, the complete catheter reconstruction was reassessed, to correct for, for example, bending of the catheters. The displacement of catheters between the MRI scans was determined by comparing the catheter tip positions on the treatment planning and posttreatment 1.5 T MRI scans. Results The displacements of 241 catheters were investigated. Average (range) displacements of the umbrella catheters are 0.6 (0–2.9) mm in the x-direction, 0.5 (0–2.1) mm in the y-direction, and 0.9 (0–5.5) mm in the z-direction. In 3 patients, the displacement was >4 mm and up to 5.5 mm. This occurred in respectively 1/13, 1/16, and 1/18 catheters in these patients. The dosimetric differences between the intraoperative treatment and the posttreatment plans were in most patients less than 1.5 Gy. In 4 patients, a dose difference in clinical target volume D95 of >2 Gy up to 5.8 Gy was reported. No discrimination can be made between dose differences due to catheter displacement and/or organ movement/anatomy changes. Conclusions In general, catheter displacements were in the order of a mm and differences in dose to the clinical target volume and the organs at risk between the treatment and posttreatment plans smaller than 1.5 Gy. In some patients, dose differences up to 5.8 Gy were determined, due to either individual larger catheter displacement and/or anatomy changes. A longer followup is necessary to assess the clinical implications of individual large dose differences. |
| Databáze: | OpenAIRE |
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