A study to assess the feasibility of using CT (±diagnostic MRI) instead of MRI at brachytherapy in image guided brachytherapy in cervical cancer (original) (raw)
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CT or MRI for Image-based Brachytherapy in Cervical Cancer
Japanese Journal of Clinical Oncology, 2012
To compare volumes and doses of tumour and organs at risk with computed tomography vs. magnetic resonance imaging in cervical cancer brachytherapy. Methods: Seventeen previously untreated patients with cervical cancer suitable for radical treatment were included. All patients underwent brachytherapy using a magnetic resonance imaging-compatible applicator followed by both computed tomography and magnetic resonance imaging. The tumour and organs at risk (bladder, rectum, sigmoid and intestines) were contoured on computed tomography using only clinical findings and on magnetic resonance imaging using GEC-ESTRO guidelines. The volume and doses for tumour and organs at risk were evaluated using two-sided t-test. Results: When magnetic resonance imaging information is not included in contouring on computed tomography images, there is significant underestimation of tumour height and overestimation of the width (P , 0.05). However, there was no significant difference in V 100 , D 90 and D 100 for high-and intermediate-risk clinical target volume in computed tomography and magnetic resonance imaging. The volumes and doses to 0.1, 1 and 2 cc for organs at risk were also similar. Conclusions: Magnetic resonance imaging remains the gold standard for tumour delineation, but computed tomography with clinical information can give comparable results, which need to be studied further. Computed tomography-based contouring can be used comfortably for delineation of organs at risk.
International Journal of Radiation Oncology*Biology*Physics, 2014
Purpose/Objective-To create and compare consensus clinical target volume (CTV) contours for computed tomography (CT) and 3 Tesla (3T) magnetic resonance (MR) image-based cervicalcancer brachytherapy Materials/Methods-Twenty-three gynecologic radiation oncology experts contoured the same 3 cervical-cancer brachytherapy cases: one Stage IIB near-complete response (CR) case with a tandem and ovoid, one Stage IIB partial response (PR) case with ovoid with needles and one Stage IB2 CR case with a ring applicator. CT contours were completed before MRI contours. These were analyzed for consistency and clarity of target delineation using an expectation maximization algorithm for simultaneous truth and performance level estimation (STAPLE), with kappa statistics as a measure of agreement between participants. The conformity index (CI) was calculated for each of the six data sets. Dice coefficients were generated to compare CT and MR contours of the same case. Results-For all 3 cases, the mean tumor volume was smaller on MR than on CT (p<0.001). Kappa and CI estimates were slightly higher for CT, indicating a higher level of agreement on CT. DICE coefficients were 89% for the Stage IB2 case with a CR, 74% for the Stage IIB case with a PR, and 57% for the Stage IIB case with a CR. Conclusion-When comparing MR-to CT-contoured CTV volumes, the higher level of agreement on CT may be due to the more distinct contrast visible on the images at the time of brachytherapy. The largest difference at the time of brachytherapy was in the case with parametrial extension at diagnosis that had a near-complete response, due to the appearance of the parametria on CT but not on MR. Based on these results, a 95% consensus volume was generated for CT and for MR.
Journal of Contemporary Brachytherapy
Purpose: The dose distributions obtained from three imaging approaches for target delineation in cervical cancer using high-dose-rate (HDR) brachytherapy were investigated. Material and methods: Ten cervical cancer patients receiving four fractions of HDR brachytherapy were enrolled. Based on different imaging approaches, three brachytherapy plans were developed for each patient: with the high-risk clinical target volume (HRCTV) delineated on magnetic resonance (MRI) images for every fraction (approach A; MRIonly); on MRI for the first fraction and computed tomography (CT) images for the subsequent fractions (approach B; MRI 1st /CT); and on CT images for all fractions (approach C; CT-only). The volume, height, width at point A, width at maximum level, and dosimetric parameters (D 100 , D 98 , D 95 , and D 90 of the HRCTV; and D 0.1cc , D 1cc , and D 2cc of all organs at risk, or organ at risk-OAR: bladder, rectum, sigmoid colon, and bowel) provided by each approach were compared. Results: The mean HRCTV volume, width, and height obtained from approach C (CT-only) were overestimated compared to those from approaches A (MRI-only) and B (MRI 1st /CT). The doses to the HRCTV for approaches A and B were similar. However, the HRCTV doses for approach C were significantly lower than those for approaches A and B for all parameters (D 95-D 100). As to the OAR, the three approaches showed no differences. Conclusions: A combination of MRI and CT is a safe alternative approach for cervical cancer HDR brachytherapy. The technique provides comparable dosimetric outcomes to MRI-based planning, while being more cost-effective.
Brachytherapy, 2017
To evaluate the long-term disease control and toxicity to the organs at risk after dose-escalated image-based adaptive brachytherapy (BT) in cervical cancer. Sixty patients of cervical cancer were treated with external radiotherapy 46 Gy in 23 fractions with weekly cisplatin and MRI-guided BT 7 Gy × 4 fractions with a minimum dose of 85.7 Gy (EQD2) to the high-risk clinical target volume (HRCTV). The BT dose was initially prescribed to point A and plans were optimized to ensure coverage of both point A and HRCTV while maintaining doses to the organs at risk within the recommended constraints. Patients were followed up clinically every three months for the first two years and six months thereafter. Toxicity scoring for urinary and bowel symptoms was done using CTCAE version 3.0. The mean doses to the point A and D90 HRCTV were 85.5 (±2.75) Gy and 98.4 (±9.6) Gy EQD2 respectively. The mean 2 cc EQD2, the bladder, rectum, and sigmoid were 90.6 Gy, 70.2 Gy, and 74.2 Gy respectively. The...
Toxicities and dose-volume histogram parameters of MRI-based brachytherapy for cervical cancer
Brachytherapy
To analyze the toxicities and dose-volume histogram parameters of external-beam and magnetic resonance imaging-based intracavitary brachytherapy in cervical cancer patients. Acute and late toxicities were assessed in 135 patients divided into four groups: group 1, grade 0; group 2, grades 1-4; group 3, grades 0-1; and group 4, grades 2-4. The doses at the International Commission on Radiation Units and Measurements (DICRU) and minimum doses to the most exposed 0.1, 1, 2, and 5 cc (D0.1cc, D1cc, D2cc, and D5cc) of normal organs were calculated as equivalent doses in 2 Gy (α/β = 3). The median follow-up was 35.2 months. For rectum, DICRU, D0.1cc, D1cc, and D2cc were significantly different between groups 1 and 2 and DICRU, D0.1cc, and D1cc between groups 3 and 4. For bladder, D0.1cc, D1cc, and D2cc were significantly different between groups 1 and 2 and DICRU, D1cc, D2cc, and D5cc between groups 3 and 4. Grade 2-4 bladder toxicity occurred in fewer patients with D2cc ≤ 95 Gy than thos...
International Journal of Radiation Oncology Biology Physics, 2004
Society for Therapeutic Radiology and Oncology (ASTRO), proposed guidelines for image-based brachytherapy for cervical cancer. This report was based on their aggregate clinical experience and a review of the literature. It reflects only the personal opinions of the authors and is not meant to be an endorsement from any of the above organizations. Results: The Group recommended T 2 -weighted MRI using a pelvic surface coil with MRI-compatible brachytherapy applicators in place for image-based intracavitary brachytherapy for cervical cancer. Imaging must be performed with the patient in the treatment position, with all other treatment conditions duplicated as closely as possible. Future use of positron emission tomography or positron emission tomography/CT may obviate the need for special applicators. The group proposed the following terminology for image-based brachytherapy. The GTV (I) is defined as the gross tumor volume as defined through imaging, GTV is defined as the GTV (I) plus any clinically visualized or palpable tumor extensions, and GTV ؉ cx is defined as the GTV plus the entire cervix. The dose-volume histograms (DVH) of the GTV, GTV (I) , GTV ؉ cx should be performed, and the dose to 100%, 95%, or 90% of the GTV (D 100 , D 95 , and D 90 , respectively) and the percentage of the GTV covered by Point A dose (V 100 ) should be reported. Similarly, the DVH of the bladder and rectum wall should be performed, and the maximal dose at any point within the bladder and rectal wall should be reported, along with the maximal dose to a contiguous 1, 2, and 5 cm 3 volume of the bladder and rectum, respectively. In addition, the dose at the International Commission on Radiation Units and Measurements reference point for the bladder and rectum should be reported. The Group thought that the current dose prescription method in use for cervical cancer brachytherapy (i.e., to prescribe to Point A in most institutions) should not be changed as yet, because image-based dosimetry is not ready for routine practice. The Group proposes that for research purposes, individual centers and cooperative groups (e.g., GOG, RTOG, ACRIN) collect image-based dosimetry information and perform DVHs and correlate these data with the clinical outcome to determine which of the above parameters are relevant. The Group encourages external funding for image-based dosimetry and recommends that brachytherapy manufacturers develop image-compatible applicators. Conclusion: Although current institutional brachytherapy prescription for cervical cancer should continue, image-based data collection and analysis are needed to optimize cervical cancer brachytherapy. Proposals are made for research in image-based brachytherapy for cervical cancer.
Point A vs. HR-CTV D90 in MRI-based cervical brachytherapy of small and large lesions
Brachytherapy, 2016
To evaluate the dosimetric benefits of MRI-based brachytherapy in small and large high-risk clinical target volume (HR-CTV) in cervical cancer. Twenty-eight fractions obtained from sixteen cervical cancer patients treated with MRI-based high-dose-rate brachytherapy with standard tandem and ovoid applicators were used; original fractions were optimized to HR-CTV D90. Fractions were separated based on the median volume into small and large (HR-CTV <25 cm(3) or >25 cm(3)) lesion groups. Retrospective plans prescribed to Point A were created for each fraction. D0.1 cc, D2 cc, and International Commission of Radiation Unit and Measurements (ICRU) points were used to compare Point A vs. HR-CTV D90 plans for bladder, rectum, and sigmoid. In the small lesion group, Point A plans vs. HR-CTV D90 plans had significantly higher D0.1 cc, D2 cc, and ICRU points for bladder, rectum, and sigmoid (p < 0.05). In the large lesion group, there was no significant difference between Point A and ...
Journal of Radiation Research, 2012
This study was performed to evaluate the feasibility of magnetic resonance imaging (MRI) in the treatment planning of image-guided brachytherapy for cervical carcinoma. Seventeen consecutive patients with locally advanced cervical cancer were enrolled in the study. Fifteen patients could be evaluated. When comparing the tumor at diagnosis (GTV-Dx) and the tumor at the first brachytherapy (GTV-BT), 11 of 15 patients showed a tumor regression of more than 80% while only four patients had less than 80% tumor regression. The mean D90 of HR-CTV and the calculated D2cc of the bladder, rectum, and sigmoid were 99.2 ± 11 Gy, 87.7 ± 5.7 Gy, 68.4 ± 5.4 Gy and 70.3 ± 6.8 Gy, respectively. No grade 3-4 acute toxicity was observed. The MRI can be a valuable tool for evaluating tumor response after external beam radiotherapy (EBRT) and is very helpful for prognosis prediction by residual GTV evaluation. Furthermore, MRI-guided brachytherapy allowed us to optimize the dose for both the target volumes and the OARs.
Int J Radiation Oncol Biol Phys, 2018
Target-volume definition and delineation (high risk) at the time of brachytherapy (BT) is an important step in image guided adaptive BT for cer-vical cancer. We present the first prospective study comparing computed tomographyebased target Purpose: Although magnetic resonance imaging (MRI) represents the gold standard for image guided adaptive brachytherapy (IGABT) for cervical cancer, the majority of brachytherapy (BT) continues to be guided by computed tomography (CT). However, CT seems to overestimate the target-volume definition, and the potential of transrectal ul-trasonography (TRUS) needs further evaluation. This prospective, comparative study aimed to evaluate CT-based target contouring with the incorporation of TRUS during BT. Methods and Materials: Patients with locally advanced cervical cancer undergoing magnetic resonance IGABT between January 2013 and March 2014 were included. During the BT procedure, TRUS imaging with central tandem in situ was acquired at 3 representative levels. Reference points/dimensions (D1-D4) of the hypoechoic region on TRUS images with respect to the central tandem were recorded. CT and magnetic resonance BT planning imaging was performed after BT application. The high-risk clinical target vol- ume (HR-CTV) was contoured on CT scans with incorporation of clinical and TRUS im- aging findings and was compared with the gold standard MRI-based target approach. Results: The image sets of 25 patients (International Federation of Gynecology and Obstet- rics clinical stage IIB [11; 44%] and IIIB [14; 56%]) were evaluable. The mean (`standard deviation) volumes of HR-CTVon CT and MRI imaging were 39.1 (`20) cm3 and 39 (`19) cm3, respectively (r Z 0.92; P <.001). A significant correlation was found between the HR- CTV dimensions (width and thickness) of CT and MRI scans at various levels (r Z 0.70- 0.80; P < .001). In addition, the absolute differences in target dimensions between CT and MRI were <0.5 cm. A strong correlation was seen between CT and MRI for patients with medial and lateral parametrial invasion (P < .05) compared with no parametrial disease at BT. Furthermore, the mean differences in HR-CTV width between CT and MRI contours at various levels, irrespective of parametrial involvement, was only 0.1 to 0.4 cm. Conclusions: This study suggests that a CT-based target and organ-at-risk delineation using MRI at diagnosis and real-time TRUS information during BT seems comparable with the gold standard MRI-based approach in IGABT for cervical cancer. ! 2018 Elsevier Inc. All rights reserved.