skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

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. 2016. "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 = 2016,
month = 7
}
  • Purpose: The inhomogeneity correction factor (ICF) method provides heterogeneity correction for the fast calculation TG43 formalism in seed brachytherapy. This study compared ICF-corrected plans to their standard TG43 counterparts, looking at their capacity to assess inadequate coverage and/or risk of any skin toxicities for patients who received permanent breast seed implant (PBSI). Methods and Materials: Two-month postimplant computed tomography scans and plans of 140 PBSI patients were used to calculate dose distributions by using the TG43 and the ICF methods. Multiple dose-volume histogram (DVH) parameters of clinical target volume (CTV) and skin were extracted and compared for both ICF and TG43more » dose distributions. Short-term (desquamation and erythema) and long-term (telangiectasia) skin toxicity data were available on 125 and 110 of the patients, respectively, at the time of the study. The predictive value of each DVH parameter of skin was evaluated using the area under the receiver operating characteristic (ROC) curve for each toxicity endpoint. Results: Dose-volume histogram parameters of CTV, calculated using the ICF method, showed an overall decrease compared to TG43, whereas those of skin showed an increase, confirming previously reported findings of the impact of heterogeneity with low-energy sources. The ICF methodology enabled us to distinguish patients for whom the CTV V{sub 100} and V{sub 90} are up to 19% lower compared to TG43, which could present a risk of recurrence not detected when heterogeneity are not accounted for. The ICF method also led to an increase in the prediction of desquamation, erythema, and telangiectasia for 91% of skin DVH parameters studied. Conclusions: The ICF methodology has the advantage of distinguishing any inadequate dose coverage of CTV due to breast heterogeneity, which can be missed by TG43. Use of ICF correction also led to an increase in prediction accuracy of skin toxicities in most cases.« less
  • Purpose: A permanent breast seed implant (PBSI) technique has been developed as a new form of partial adjuvant radiation therapy for early-stage breast cancer. This study compares iodine-125 ({sup 125}I) and palladium-103 ({sup 103}Pd) isotopes by examining the exposure and effective dose (ED) to a patient's partner.Methods and Materials: A low-energy survey meter was used to measure exposure rates as a function of bolus thickness placed over {sup 103}Pd or {sup 125}I seeds. A general mathematical expression for the initial exposure rate at 1 m (x{sub o,1m}) from the skin surface as a function of the implant size, R, andmore » the distance between the skin surface and the implant, d, was derived. Also, a second general equation is proposed to calculate the ED to the patient's partner.Results: The initial exposure rate at 1 meter and the ED are calculated as follows: x{sub o,1m} = (3{alpha})/2R{sup 3}{center_dot}{beta}{sup 3} [e{sup -{beta}}{sup (2R+d)}({beta}R + 1) + e{sup -{beta}}{sup {center_dot}}{sup d}({beta}R - 1)], and ED = aR{sup b} {center_dot} [e{sup -c(2R+d)} {center_dot} (cR + 1) + e{sup -cd} -bar (cR - 1)]. For {sup 125}I, the parameters are: {alpha} = 0.154409, {beta} = 0.388460, a = 197, b = -0.95, and c = 0.38846. For {sup 103}Pd, they are: {alpha} = 0.06877, {beta} = 0.421098, a = 18.6, b -0.78, and c = 0.421098. For implant diameters varying from 2 to 6 cm and skin-to-implant distances varying from 0.7 to 4 cm, the ED is consistently below 2.6 mSv using the {sup 103}Pd isotope, but more than 5 mSv in many instances and possibly up to 20 mSv using {sup 125}I.Conclusions: PBSI using {sup 103}Pd seeds appears safe because the patient's partner ED is consistently below 5 mSv. The{sup 125}I isotope is not recommended for PBSI.« less
  • Purpose: A new technique of adjuvant partial breast irradiation using {sup 103}Pd permanent breast seed implants (PBSI) is presented. The procedure is performed in a single 1-hour session under local anesthesia. Methods and Materials: Patients referred to a single institution for adjuvant radiotherapy after lumpectomy for an infiltrating ductal carcinoma {<=}3 cm in diameter, surgical margin {>=}2 mm, no extensive in situ carcinoma, no lymphovascular invasion, and minimal or negative lymph node involvement were offered a PBSI. Results: Between May and December 2004, 31 eligible patients underwent CT scan and ultrasound simulations assessing PBSI feasibility. Fifteen were excluded because ofmore » feasibility issues, and 16 received PBSI. A minimal peripheral dose of 90 Gy was prescribed to the planning target volume corresponding to the clinical target volume identified on the CT scan plus a margin of 1 cm. The procedure was well tolerated; 56% of the patients reported no pain during the procedure, and 46% of the patients developed National Cancer Institute Common Toxicity Criteria Grade 1 acute reaction. None experienced toxicity Grade 2 or 3. Conclusions: Permanent breast seed implantation seems feasible and well tolerated on these preliminary clinical data and represents an ultimate step in the reduction of treatment fraction for partial breast irradiation.« less
  • Purpose: The aim of this study was to use permanent seed implants in the breast and describe our experience with 15 cases, using iodine seed implants as a tumor bed boost. Methods and Materials: Breasts were fixed with a thermoplastic sheet, a template bridge applied, the thorax scanned and the images rotated to be perpendicular to the implant axis. Skin, heart, and lung were delineated. A preplan was made, prescribing 50 Gy to the clinical target volume (CTV), consisting in this boost series of nearly a quadrant. Iodine (125) seeds were stereotactically implanted through the template, and results were checkedmore » with a postplan computed tomographic (CT) scan. Results: The breast was immobilized reproducibly. Simulation, scanning, and implant were performed without difficulties. Preplan CTV D90% (the dose delivered to 90% of the CTV) was 66 Gy, and postoperative fluoroscopic or CT scan checks were satisfactory. Pre- and postplan dose-volume histogram showed good organ sparing: mean postplan skin, heart, and lung V30 Gy (the organ volume receiving a dose of 30 Gy) of 2 {+-} 2.2 mL, 0.24 {+-} 0.34 mL, and 3.5 {+-} 5 mL, respectively. No short-term toxicity above Grade 1 was noted, except for transient Grade 3 neuropathy in 1 patient. Conclusions: Seeds remained in the right place, as assessed by fluoroscopy, absence of significant pre- to postplan dose-volume histogram change for critical organs, and total irradiated breast volume. The method could be proposed as a boost when high dosimetric selectivity is required (young patients after cardiotoxic chemotherapy for left-sided cancer). This boost series was a preliminary step before testing partial breast irradiation by permanent seed implant in a prospective trial.« less
  • Purpose: Permanent breast seed implant is an accelerated partial breast irradiation technique realizing the insertion of {sup 103}Pd seeds in the seroma after lumpectomy. We report the 5-year efficacy and tolerance for a cohort, pooling patients from 3 clinical trials. Methods and Materials: The trials accrued postmenopausal patients with infiltrating ductal carcinoma or ductal carcinoma in situ ≤3 cm and clear surgical margins, who were node negative, and had a planning target volume <120 cm{sup 3}. The outcomes included overall and disease-free survival and local and contralateral recurrence at 5 years. The true local recurrence rate was compared using 2-tailed paired t testsmore » for estimates calculated using the Tufts University ipsilateral breast tumor recurrence and Memorial Sloan Kettering ductal carcinoma in situ nomograms. Results: The cohort included 134 patients, and the observed local recurrence rate at a median follow-up period of 63 months was 1.2% ± 1.2%, similar to the estimate for whole breast irradiation (P=.23), significantly better than for surgery alone (relative risk 0.27; P<.001), and significantly lower than contralateral recurrence (relative risk 0.33; P<.001). The 5-year overall survival rate was 97.4% ± 1.9%, and the disease-free survival rate was 96.4% ± 2.1%. At 2 months, 42% of the patients had erythema, 20% induration, and 16% moist desquamation. The rate of mainly grade 1 telangiectasia was 22.4% at 2 years and 24% at 5 years. The rate of asymptomatic induration was 23% at 2 years and 40% at 5 years. Conclusions: The 5-year data suggest that permanent breast seed implantation is a safe accelerated partial breast irradiation option after lumpectomy for early-stage breast cancer with a tolerance profile similar to that of whole breast irradiation.« less