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Title: Seed Placement in Permanent Breast Seed Implant Brachytherapy: Are Concerns Over Accuracy Valid?

Abstract

Purpose: To evaluate seed placement accuracy in permanent breast seed implant brachytherapy (PBSI), to identify any systematic errors and evaluate their effect on dosimetry. Methods and Materials: Treatment plans and postimplant computed tomography scans for 20 PBSI patients were spatially registered and used to evaluate differences between planned and implanted seed positions, termed seed displacements. For each patient, the mean total and directional seed displacements were determined in both standard room coordinates and in needle coordinates relative to needle insertion angle. Seeds were labeled according to their proximity to the anatomy within the breast, to evaluate the influence of anatomic regions on seed placement. Dosimetry within an evaluative target volume (seroma + 5 mm), skin, breast, and ribs was evaluated to determine the impact of seed placement on the treatment. Results: The overall mean (±SD) difference between implanted and planned positions was 9 ± 5 mm for the aggregate seed population. No significant systematic directional displacements were observed for this whole population. However, for individual patients, systematic displacements were observed, implying that intrapatient offsets occur during the procedure. Mean displacements for seeds in the different anatomic areas were not found to be significantly different from the mean for the entire seed population. However, smallmore » directional trends were observed within the anatomy, potentially indicating some bias in the delivery. Despite observed differences between the planned and implanted seed positions, the median (range) V{sub 90} for the 20 patients was 97% (66%-100%), and acceptable dosimetry was achieved for critical structures. Conclusions: No significant trends or systematic errors were observed in the placement of seeds in PBSI, including seeds implanted directly into the seroma. Recorded seed displacements may be related to intrapatient setup adjustments. Despite observed seed displacements, acceptable postimplant dosimetry was achieved.« less

Authors:
 [1];  [2];  [1];  [2];  [1];  [3]
  1. Department of Medical Physics, BC Cancer Agency, Centre for the Southern Interior, Kelowna, British Columbia (Canada)
  2. (Canada)
  3. Department of Radiation Oncology, BC Cancer Agency, Centre for the Southern Interior, Kelowna, British Columbia (Canada)
Publication Date:
OSTI Identifier:
22648719
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 95; Journal Issue: 3; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; BRACHYTHERAPY; COMPUTERIZED TOMOGRAPHY; DOSIMETRY; MAMMARY GLANDS; PATIENTS; RADIATION SOURCE IMPLANTS

Citation Formats

Morton, Daniel, E-mail: dmorton@bccancer.bc.ca, Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Hilts, Michelle, Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Batchelar, Deidre, and Crook, Juanita. Seed Placement in Permanent Breast Seed Implant Brachytherapy: Are Concerns Over Accuracy Valid?. United States: N. p., 2016. Web. doi:10.1016/J.IJROBP.2016.01.049.
Morton, Daniel, E-mail: dmorton@bccancer.bc.ca, Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Hilts, Michelle, Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Batchelar, Deidre, & Crook, Juanita. Seed Placement in Permanent Breast Seed Implant Brachytherapy: Are Concerns Over Accuracy Valid?. United States. doi:10.1016/J.IJROBP.2016.01.049.
Morton, Daniel, E-mail: dmorton@bccancer.bc.ca, Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Hilts, Michelle, Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Batchelar, Deidre, and Crook, Juanita. Fri . "Seed Placement in Permanent Breast Seed Implant Brachytherapy: Are Concerns Over Accuracy Valid?". United States. doi:10.1016/J.IJROBP.2016.01.049.
@article{osti_22648719,
title = {Seed Placement in Permanent Breast Seed Implant Brachytherapy: Are Concerns Over Accuracy Valid?},
author = {Morton, Daniel, E-mail: dmorton@bccancer.bc.ca and Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia and Hilts, Michelle and Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia and Batchelar, Deidre and Crook, Juanita},
abstractNote = {Purpose: To evaluate seed placement accuracy in permanent breast seed implant brachytherapy (PBSI), to identify any systematic errors and evaluate their effect on dosimetry. Methods and Materials: Treatment plans and postimplant computed tomography scans for 20 PBSI patients were spatially registered and used to evaluate differences between planned and implanted seed positions, termed seed displacements. For each patient, the mean total and directional seed displacements were determined in both standard room coordinates and in needle coordinates relative to needle insertion angle. Seeds were labeled according to their proximity to the anatomy within the breast, to evaluate the influence of anatomic regions on seed placement. Dosimetry within an evaluative target volume (seroma + 5 mm), skin, breast, and ribs was evaluated to determine the impact of seed placement on the treatment. Results: The overall mean (±SD) difference between implanted and planned positions was 9 ± 5 mm for the aggregate seed population. No significant systematic directional displacements were observed for this whole population. However, for individual patients, systematic displacements were observed, implying that intrapatient offsets occur during the procedure. Mean displacements for seeds in the different anatomic areas were not found to be significantly different from the mean for the entire seed population. However, small directional trends were observed within the anatomy, potentially indicating some bias in the delivery. Despite observed differences between the planned and implanted seed positions, the median (range) V{sub 90} for the 20 patients was 97% (66%-100%), and acceptable dosimetry was achieved for critical structures. Conclusions: No significant trends or systematic errors were observed in the placement of seeds in PBSI, including seeds implanted directly into the seroma. Recorded seed displacements may be related to intrapatient setup adjustments. Despite observed seed displacements, acceptable postimplant dosimetry was achieved.},
doi = {10.1016/J.IJROBP.2016.01.049},
journal = {International Journal of Radiation Oncology, Biology and Physics},
number = 3,
volume = 95,
place = {United States},
year = {Fri Jul 01 00:00:00 EDT 2016},
month = {Fri Jul 01 00:00:00 EDT 2016}
}