A Prospective Comparison of Computed Tomography with Transrectal Ultrasonography Assistance and Magnetic Resonance ImagingeBased Target-Volume Definition During Image Guided Adaptive Brachytherapy for Cervical Cancers (original) (raw)
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Radiation Oncology, 2020
Purpose To compare CTVHR and OAR dimensions and inter-rater agreement between magnetic resonance (MR) and trans-rectal ultrasound (TRUS) images in IB cervical cancer patients. Methods IB cervical cancer patients treated with (chemo)radiotherapy plus MR-guided brachytherapy (BT) were prospectively enrolled in this study. Radiation oncologists contoured CTVHR and OARs in pre-BT MR images (MRI) and intra-operative TRUS images. These contours were subsequently compared in regard to volume and dimension. Contour inter-rater agreement analysis was also investigated using kappa index (KI). Stata 15.0 was used for statistical analysis and a p-value < 0.05 was considered statistically significant. Results TRUS CTVHR volumes were statistically smaller than the respective MRI contoured volumes. TRUS CTVHR thickness was found to be consistently smaller than MRI contours in all patients. No statistical difference was seen in width and height between the two different imaging modalities. MRI c...
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.
International journal of radiation oncology, biology, physics, 2016
To define, in the setting of cervical cancer, to what extent information from additional pretreatment magnetic resonance imaging (MRI) without the brachytherapy applicator improves conformity of CT-based high-risk clinical target volume (CTVHR) contours, compared with the MRI for various tumor stages (International Federation of Gynecology and Obstetrics [FIGO] stages I-IVA). The CTVHR was contoured in 39 patients with cervical cancer (FIGO stages I-IVA) (1) on CT images based on clinical information (CTVHR-CTClinical) alone; and (2) using an additional MRI before brachytherapy, without the applicator (CTVHR-CTpre-BT MRI). The CT contours were compared with reference contours on MRI with the applicator in place (CTVHR-MRIref). Width, height, thickness, volumes, and topography were analyzed. The CT-MRIref differences hardly varied in stage I tumors (n=8). In limited-volume stage IIB and IIIB tumors (n=19), CTVHR-CTpre-BT MRI-MRIref volume differences (2.6 cm(3) [IIB], 7.3 cm(3) [IIIB...
Acta Oncologica, 2013
Purpose. The aim of the study was to improve computed tomography (CT)-based high-risk clinical target volume (HR CTV) delineation protocols for cervix cancer patients, in settings without any access to magnetic resonance imaging (MRI) at the time of brachytherapy. Therefore the value of a systematic integration of comprehensive three-dimensional (3D) documentation of repetitive gynecological examination for CT-based HR CTV delineation protocols, in addition to information from FIGO staging, was investigated. In addition to a comparison between reference MRI contours and two different CT-based contouring methods (using complementary information from FIGO staging with or without additional 3D clinical drawings), the use of standardized uterine heights was also investigated. Material and methods. Thirty-fi ve cervix cancer patients with CT-and MR-images and 3D clinical drawings at time of diagnosis and brachytherapy were included. HR CTV stage was based on CT information and FIGO stage. HR CTV stage ϩ 3Dclin was contoured on CT using FIGO stage and 3D clinical drawing. Standardized HR CTV heights were: 1/1, 2/3 and 1/2 of uterine height. MRI-based HR CTV was delineated independently. Resulting widths, thicknesses, heights, and volumes of HR CTV stage , HR CTV stage ϩ 3Dclin and MRI-based HR CTV contours were compared. Results. The overall normalized volume ratios (mean Ϯ SD of CT/MRI ref volume) of HR CTV stage and HR stage ϩ 3Dclin were 2.6 ( Ϯ 0.6) and 2.1 ( Ϯ 0.4) for 1/1 and 2.3 ( Ϯ 0.5) and 1.8 ( Ϯ 0.4), for 2/3, and 1.9 ( Ϯ 0.5) and 1.5 ( Ϯ 0.3), for 1/2 of uterine height. The mean normalized widths were 1.5 Ϯ 0.2 and 1.2 Ϯ 0.2 for HR CTV stage and HR CTV stage ϩ 3Dclin , respectively (p Ͻ 0.05). The mean normalized heights for HR CTV stage and HR CTV stage ϩ 3Dclin were both 1.7 Ϯ 0.4 for 1/1 (p Ͻ 0.05.), 1.3 Ϯ 0.3 for 2/3 (p Ͻ 0.05) and 1.1 Ϯ 0.3 for 1/2 of uterine height. Conclusion. CT-based HR CTV contouring based on FIGO stage alone leads to large overestimation of width and volume. Target delineation accuracy can systematically improve through incorporation of additional information from comprehensive 3D documentation of repetitive gynecological examination in the contouring protocol, and thus help to improve the accuracy of dose optimization in settings with limited access to imaging facilities at the time of brachytherapy. If CT information is only available, minimum 2/3 of uterine height may be a good surrogate for the height of HR CTV.
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.
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.
MRI Assessment of Cervical Cancer for Adaptive Radiotherapy
Strahlentherapie und Onkologie, 2009
To assess the importance of the information obtained from MRI for adaptive cervix cancer radiotherapy. Patients and Methods: 49 patients with cervix cancer, treated by external-beam radiotherapy (EBRT) and MRI-assisted high-dose-rate brachytherapy ± concomitant cisplatin, underwent MRI at diagnosis and at the time of brachytherapy fractions. 190 MRI examinations were performed. Pretreatment scans were correlated with clinical examination (CE) findings. Measurements in 3-D of the tumor extension and also of the distance from the tumor to the pelvic side wall were performed using both MRI and CE. The tumor volume regression induced initially by EBRT and the subsequent regression after each brachytherapy fraction were assessed. Results: MRI and CE showed 92% agreement in overall parametrial staging and 73% agreement in terms of vaginal involvement. There was, however, disagreement in parametrial side (right/left) classification in 25% of the parametria examined. These were patients with unilateral displacement of the cervix and contralateral invasion of the parametrium. The mean tumor volume on the pretreatment MRI scan (GTVD) was 61 cm 3 . At the time of the four brachytherapy fractions the mean was 16 cm 3 , 10 cm 3 , 9 cm 3 , and 8 cm 3 , defined as the GTVBT plus the gray zones in the parametria. Conclusion: CE and MRI findings agree well in terms of overall staging. The clinical assessment of side-specific parametrial invasion improved when having access to the additional knowledge obtained from MRI. The greatest decrease in tumor volume occurs during EBRT, whereas tumor regression between the first and subsequent brachytherapy fractions is minor.