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Title: SU-C-202-02: A Comprehensive Evaluation of Adaptive Daily Planning for Cervical Cancer HDR Brachytherapy

Abstract

Purpose: To evaluate adaptive daily planning for cervical cancer patients who underwent high-dose-rate intra-cavitary brachytherapy (HDR-ICBT). Methods: This study included 22 cervical cancer patients who underwent 5 fractions of HDR ICBT. Regions of interest (ROIs) including high-risk clinical tumor volume (HR-CTV) and organs-at-risk (OARs) were manually contoured on daily CT images. All patients were treated with adaptive daily plans, which involved ROI delineation and dose optimization at each treatment fraction. Single treatment plans were retrospectively generated by applying the first treatment fraction’s dwell times adjusted for decay and dwell positions of the applicator to subsequent treatment fractions. Various existing similarity metrics were calculated for the ROIs to quantify interfractional organ variations. A novel similarity score (JRARM) was established, which combined both volumetric overlap metrics (DSC, JSC, and RVD) and distance metrics (ASD, MSD, and RMSD). Linear regression was performed to determine a relationship between inter-fractional organ variations of various similarity metrics and D2cc variations from both plans. Wilcoxon Signed Rank Tests were used to assess adaptive daily plans and single plans by comparing EQD2 D2cc (α/β=3) for OARs. Results: For inter-fractional organ variations, the sigmoid demonstrated the greatest variations based on the JRARM and DSC similarity metrics. Comparisons between pairedmore » ROIs showed differences in JRARM scores and DSCs at each treatment fraction. RVD, MSD, and RMSD were found to be significantly correlated to D2cc variations for bladder and sigmoid. The comparison between plans found that adaptive daily planning provided lower EQD2 D2cc of OARs than single planning, specifically for the sigmoid (p=0.015). Conclusion: Substantial inter-fractional organ motion can occur during HDR-BT, which may significantly affect D2cc of OARs. Adaptive daily planning provides improved dose sparing for OARs compared to single planning.« less

Authors:
; ;  [1];  [2]; ;  [1];  [3]
  1. Department of Oncology, Radiation Oncology Division, Wayne State University School of Medicine, Detroit, MI (United States)
  2. Department of Oncology, Radiation Oncology Division, Karmanos Cancer Institute, Detroit, MI (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22624331
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; BIOMEDICAL RADIOGRAPHY; BLADDER; BRACHYTHERAPY; CALORIMETRY; COMPUTERIZED TOMOGRAPHY; DOSE RATES; HAZARDS; IMAGE PROCESSING; NEOPLASMS; OPTIMIZATION; PATIENTS; PLANNING; RADIATION DOSES

Citation Formats

Meerschaert, R, Paul, A, Zhuang, L, Nalichowski, A, Burmeister, J, Miller, A, and Department of Oncology, Radiation Oncology Division, Karmanos Cancer Institute, Detroit, MI. SU-C-202-02: A Comprehensive Evaluation of Adaptive Daily Planning for Cervical Cancer HDR Brachytherapy. United States: N. p., 2016. Web. doi:10.1118/1.4955570.
Meerschaert, R, Paul, A, Zhuang, L, Nalichowski, A, Burmeister, J, Miller, A, & Department of Oncology, Radiation Oncology Division, Karmanos Cancer Institute, Detroit, MI. SU-C-202-02: A Comprehensive Evaluation of Adaptive Daily Planning for Cervical Cancer HDR Brachytherapy. United States. doi:10.1118/1.4955570.
Meerschaert, R, Paul, A, Zhuang, L, Nalichowski, A, Burmeister, J, Miller, A, and Department of Oncology, Radiation Oncology Division, Karmanos Cancer Institute, Detroit, MI. 2016. "SU-C-202-02: A Comprehensive Evaluation of Adaptive Daily Planning for Cervical Cancer HDR Brachytherapy". United States. doi:10.1118/1.4955570.
@article{osti_22624331,
title = {SU-C-202-02: A Comprehensive Evaluation of Adaptive Daily Planning for Cervical Cancer HDR Brachytherapy},
author = {Meerschaert, R and Paul, A and Zhuang, L and Nalichowski, A and Burmeister, J and Miller, A and Department of Oncology, Radiation Oncology Division, Karmanos Cancer Institute, Detroit, MI},
abstractNote = {Purpose: To evaluate adaptive daily planning for cervical cancer patients who underwent high-dose-rate intra-cavitary brachytherapy (HDR-ICBT). Methods: This study included 22 cervical cancer patients who underwent 5 fractions of HDR ICBT. Regions of interest (ROIs) including high-risk clinical tumor volume (HR-CTV) and organs-at-risk (OARs) were manually contoured on daily CT images. All patients were treated with adaptive daily plans, which involved ROI delineation and dose optimization at each treatment fraction. Single treatment plans were retrospectively generated by applying the first treatment fraction’s dwell times adjusted for decay and dwell positions of the applicator to subsequent treatment fractions. Various existing similarity metrics were calculated for the ROIs to quantify interfractional organ variations. A novel similarity score (JRARM) was established, which combined both volumetric overlap metrics (DSC, JSC, and RVD) and distance metrics (ASD, MSD, and RMSD). Linear regression was performed to determine a relationship between inter-fractional organ variations of various similarity metrics and D2cc variations from both plans. Wilcoxon Signed Rank Tests were used to assess adaptive daily plans and single plans by comparing EQD2 D2cc (α/β=3) for OARs. Results: For inter-fractional organ variations, the sigmoid demonstrated the greatest variations based on the JRARM and DSC similarity metrics. Comparisons between paired ROIs showed differences in JRARM scores and DSCs at each treatment fraction. RVD, MSD, and RMSD were found to be significantly correlated to D2cc variations for bladder and sigmoid. The comparison between plans found that adaptive daily planning provided lower EQD2 D2cc of OARs than single planning, specifically for the sigmoid (p=0.015). Conclusion: Substantial inter-fractional organ motion can occur during HDR-BT, which may significantly affect D2cc of OARs. Adaptive daily planning provides improved dose sparing for OARs compared to single planning.},
doi = {10.1118/1.4955570},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = 2016,
month = 6
}
  • Purpose: To demonstrate that utilization of a novel, intensity modulation capable, direction modulated brachytherapy (DMBT) tandem applicator can improve plan quality compared with conventional T&R applicator during an image guided cervical cancer brachytherapy. Methods: 45 cervical cancer patients treated with PDR brachytherapy were reviewed. Of them, a) 27 were treated using T&R only, b) 9 were treated using T&R with needles attached to the ring, and c) the remaining 9 were treated using T&R with needles attached to the ring (AN) as well as additional free-hand-loaded needles (FN). The DMBT tandem design has 6 peripheral holes of 1.3-mm diameter, groovedmore » along a nonmagnetic tungsten alloy rod, enclosed in a plastic sheath with total 6.0-mm diameter. An in-house-coded inverse planning system was used for planning DMBT and T&R cases. All typical clinical constraints including OAR dose limits, dwell times, and loading patterns were respected. For the DMBT and T&R applicators, the plans were optimized with the same conventional ring in place, but repeatedly planned with and without AN/FN needles. All generated plans were normalized to the same D90 of the clinically treated plans. Results: For the plans in category a), DMBT generally outperformed T&R with average reduction in D2cc of −2.39%, −5.21%, and −2.69% for bladder, rectum, and sigmoid, respectively. For the plans in category b) and c), DMBT generally outperformed T&R if the same needles in AN/FN were utilized in both cases with average reduction in D2cc of −1.82%, −3.40%, and −6.04%, respectively. For the cases where the needles were not utilized for both applicators, an average D2cc reduction of −7.45%, −7.61%, and 17.47% were observed, respectively. Conclusions: Under the same clinical conditions, with/without needles, the DMBT applicator tends to generate more favorable plans compared with the conventional T&R applicator, and hence, is a promising technology.« less
  • Purpose: A dosimetric study was conducted to compare intracavitary brachytherapy using both a conventional and a custom loading intended to cover a positron emission tomography (PET)-defined tumor volume in patients with cervix cancer. Methods and Materials: Eleven patients who underwent an [{sup 18}F]-fluoro-deoxy-D-glucose (FDG)-PET in conjunction with their first, middle, or last brachytherapy treatment were included in this prospective study. A standard plan that delivers 6.5 Gy to point A under ideal conditions was compared with an optimized plan designed to conform the 6.5-Gy isodose surface to the PET defined volume. Results: A total of 31 intracavitary brachytherapy treatments inmore » conjunction with an FDG-PET were performed. The percent coverage of the target isodose surface for the first implant with and without optimization was 73% and 68% (p = 0.21). The percent coverage of the target isodose surface for the mid/final implant was 83% and 70% (p = 0.02), respectively. The dose to point A was higher with the optimized plans for both the first implant (p = 0.02) and the mid/last implants (p = 0.008). The dose to 2 cm{sup 3} and 5 cm{sup 3} of both the bladder and rectum were not significantly different. Conclusions: FDG-PET based treatment planning allowed for improved dose coverage of the tumor without significantly increasing the dose to the bladder and rectum.« less
  • Purpose: To estimate and compare the doses received by the obturator, external and internal iliac lymph nodes and point Methods: CT-MR fused image sets of 15 patients obtained for each of 5 fractions of HDR brachytherapy using tandem and ring applicator, were used to generate treatment plans optimized to deliver a prescription dose to HRCTV-D90 and to minimize the doses to organs at risk (OARs). For each set of image, target volume (GTV, HRCTV) OARs (Bladder, Rectum, Sigmoid), and both left and right pelvic lymph nodes (obturator, external and internal iliac lymph nodes) were delineated. Dose-volume histograms (DVH) were generatedmore » for pelvic nodal groups (left and right obturator group, internal and external iliac chains) Per fraction DVH parameters used for dose comparison included dose to 100% volume (D100), and dose received by 2cc (D2cc), 1cc (D1cc) and 0.1 cc (D0.1cc) of nodal volume. Dose to point B was compared with each DVH parameter using 2 sided t-test. Pearson correlation were determined to examine relationship of point B dose with nodal DVH parameters. Results: FIGO clinical stage varied from 1B1 to IIIB. The median pretreatment tumor diameter measured on MRI was 4.5 cm (2.7– 6.4cm).The median dose to bilateral point B was 1.20 Gy ± 0.12 or 20% of the prescription dose. The correlation coefficients were all <0.60 for all nodal DVH parameters indicating low degree of correlation. Only 2 cc of obturator nodes was not significantly different from point B dose on t-test. Conclusion: Dose to point B does not adequately represent the dose to any specific pelvic nodal group. When using image guided 3D dose-volume optimized treatment nodal groups should be individually identified and delineated to obtain the doses received by pelvic nodes.« less
  • The purpose of this study was to analyze the dosimetric outcome of 3D image-guided high-dose-rate (HDR) brachytherapy planning for cervical cancer treatment and compare dose coverage of high-risk clinical target volume (HRCTV) to traditional Point A dose. Thirty-two patients with stage IA2-IIIB cervical cancer were treated using computed tomography/magnetic resonance imaging-based image-guided HDR brachytherapy (IGBT). Brachytherapy dose prescription was 5.0-6.0 Gy per fraction for a total 5 fractions. The HRCTV and organs at risk (OARs) were delineated following the GYN GEC/ESTRO guidelines. Total doses for HRCTV, OARs, Point A, and Point T from external beam radiotherapy and brachytherapy were summatedmore » and normalized to a biologically equivalent dose of 2 Gy per fraction (EQD2). The total planned D90 for HRCTV was 80-85 Gy, whereas the dose to 2 mL of bladder, rectum, and sigmoid was limited to 85 Gy, 75 Gy, and 75 Gy, respectively. The mean D90 and its standard deviation for HRCTV was 83.2 {+-} 4.3 Gy. This is significantly higher (p < 0.0001) than the mean value of the dose to Point A (78.6 {+-} 4.4 Gy). The dose levels of the OARs were within acceptable limits for most patients. The mean dose to 2 mL of bladder was 78.0 {+-} 6.2 Gy, whereas the mean dose to rectum and sigmoid were 57.2 {+-} 4.4 Gy and 66.9 {+-} 6.1 Gy, respectively. Image-based 3D brachytherapy provides adequate dose coverage to HRCTV, with acceptable dose to OARs in most patients. Dose to Point A was found to be significantly lower than the D90 for HRCTV calculated using the image-based technique. Paradigm shift from 2D point dose dosimetry to IGBT in HDR cervical cancer treatment needs advanced concept of evaluation in dosimetry with clinical outcome data about whether this approach improves local control and/or decreases toxicities.« less
  • Purpose: To evaluate the predictive value of dose-volume histogram (DVH) parameters for late side effects of the rectum, sigmoid colon, and bladder in image-guided brachytherapy for cervix cancer patients. Methods and Materials: A total of 141 patients received external-beam radiotherapy and image-guided brachytherapy with or without chemotherapy. The DVH parameters for the most exposed 2, 1, and 0.1 cm{sup 3} (D{sub 2cc}, D{sub 1cc}, and D{sub 0.1cc}) of the rectum, sigmoid, and bladder, as well as International Commission on Radiation Units and Measurements point doses (D{sub ICRU}) were computed. Total doses were converted to equivalent doses in 2 Gy bymore » applying the linear-quadratic model ({alpha}/{beta} = 3 Gy). Late side effects were prospectively assessed using the Late Effects in Normal Tissues-Subjective, Objective, Management and Analytic score. The following patient groups were defined: Group 1: no side effects (Grade 0); Group 2: side effects (Grade 1-4); Group 3: minor side effects (Grade 0-1); and Group 4: major side effects (Grade 2-4). Results: The median follow-up was 51 months. The overall 5-year actuarial side effect rates were 12% for rectum, 3% for sigmoid, and 23% for bladder. The mean total D{sub 2cc} were 65 {+-} 12 Gy for rectum, 62 {+-} 12 Gy for sigmoid, and 95 {+-} 22 Gy for bladder. For rectum, statistically significant differences were observed between Groups 1 and 2 in all DVH parameters and D{sub ICRU}. Between Groups 3 and 4, no difference was observed for D{sub 0.1cc.} For sigmoid, significant differences were observed for D{sub 2cc} and D{sub 1cc}, but not for D{sub 0.1cc} in all groups. For bladder, significant differences were observed for all DVH parameters only comparing Groups 3 and 4. No differences were observed for D{sub ICRU}. Conclusions: The parameters D{sub 2cc} and D{sub 1cc} have a good predictive value for rectal toxicity. For sigmoid, no prediction could be postulated because of limited data. In bladder, DVH parameters were predictive only for major toxicity.« less