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Purpose: High-dose-rate (HDR) prostate brachytherapy uses volumetric imaging for treatment planning. Our institution transitioned from computed tomography (CT)-based planning to MRI-based planning with the hypothesis that improved visualization could reduce treatment-related toxicity. This study aimed to compare the patient-reported health-related quality of life (hrQOL) and physician-graded toxicity outcomes of CT-based and MRI-based HDR prostate brachytherapy., Methods: From 2016 to 2019, 122 patients with low- or intermediate-risk prostate cancer were treated with HDR brachytherapy as monotherapy. Patients underwent CT only or CT and MRI imaging for treatment planning and were grouped per treatment planning imaging modality. Patient-reported hrQOL in the genitourinary (GU), gastrointestinal (GI), and sexual domains was assessed using International Prostate Symptom Score and Expanded Prostate Cancer Index Composite Short Form-26 questionnaires. Baseline characteristics, changes in hrQOL scores, and physician-graded toxicities were compared between groups., Results: The median follow-up was 18 months. Patient-reported GU, GI, and sexual scores worsened after treatment but returned toward baseline over time. The CT cohort had a lower baseline mean International Prostate Symptom Score (5.8 vs. 7.8, p = 0.03). The other patient-reported GU and GI scores did not differ between groups. Overall, sexual scores were similar between the CT and MRI cohorts (p = 0.08) but favored the MRI cohort at later follow-up with a smaller decrease in Expanded Prostate Cancer Index Composite Short Form-26 sexual score from baseline at 18 months (4.9 vs. 19.8, p = 0.05). Maximum physician-graded GU, GI, and sexual toxicity rates of grade ≥2 were 68%, 3%, and 53%, respectively, with no difference between the cohorts (p = 0.31)., Conclusion: Our study shows that CT- and MRI-based HDR brachytherapy results in similar rates of GU and GI toxicity. MRI-based planning may result in improved erectile function recovery compared with CT-based planning., (Published by Elsevier Inc.)

Purpose/objective(s): To evaluate dosimetric differences between MRI-only and MRI-CT planning with a titanium tandem and ovoid applicator to determine if all imaging and planning goals can be achieved with MRI only., Materials/methods: We evaluated 10 patients who underwent MRI-CT-based cervical brachytherapy with a titanium tandem and ovoid applicator. High-risk clinical target volume and organs at risk were contoured on the 3D T2 MRI, which were transferred to the co-registered CT, where the applicator was identified. Retrospectively, three planners independently delineated the applicator on the axial 3D T2 MRI while blinded to the CT. Identical dwell position times in the delivered plan were loaded. Dose-volume histogram parameters were compared to the previously delivered MRI-CT plan., Results: There were no significant differences in dose to D 90 or D 98 of the high-risk clinical target volume with MRI vs. MRI-CT planning. MRI vs. MRI-CT planning resulted in mean D 0.1cc bladder of 8.8 ± 3.4 Gy vs. 8.5 ± 3.2 Gy (p = 0.29) and D 2cc bladder of 6.2 ± 1.4 Gy vs. 6.0 ± 1.4 Gy (p = 0.33), respectively. Mean D 0.1cc rectum was 5.7 ± 1.2 Gy vs. 5.3 ± 1.2 Gy (p = 0.03) and D 2cc rectum 4.0 ± 0.8 Gy vs. 4.2 ± 1.0 Gy (p = 0.18), respectively. Mean D 0.1cc sigmoid was 5.2 ± 1.3 Gy vs. 5.4 ± 1.6 Gy (p = 0.23) and D 2cc sigmoid 3.9 ± 1.0 Gy vs. 4.0 ± 1.1 Gy (p = 0.18), respectively., Conclusion: There were no clinically significant dosimetric differences between the MRI and MRI-CT plans. This study demonstrates that cervical brachytherapy with a titanium applicator can be planned with MRI alone, which is now our clinical standard., (Published by Elsevier Inc.)

Purpose: To demonstrate that optimized pulse sequence parameters for a T2-weighted (T2w) fast spin echo acquisition reduced artifacts from a titanium brachytherapy applicator compared to conventional sequence parameters., Methods and Materials: Following Institutional Review Board approval and informed consent, seven patients were successfully imaged with both standard sagittal T2w fast spin echo parameters (voxel size of 0.98 × 0.78 × 4.0 mm 3 ; readout bandwidth of 200 Hz/px; repetition time of 2800 ms; echo time of 91 ms; echo train length of 15; 36 slices; and imaging time of 3:16 min) and an additional optimized T2w sequence (voxel size of 0.98 × 0.98 × 4.0 mm 3 ; readout bandwidth of 500 Hz/px; repetition time of 3610 ms; echo time of 91 ms; echo train length of 25; 18-36 slices; and imaging time of 1:15-2:30 min), which had demonstrated artifact reduction in prior phantom work. Visualized intracavitary tandem was hand-segmented by two of the authors. Three body imaging radiologists assessed image quality and intraobserver agreement scores were analyzed., Results: The average segmented volume of the intracavitary applicator significantly (p < 0.05) decreased with the experimental pulse sequence parameters as compared to the standard pulse sequence. Comparison of experimental and standard T2w sequence qualitative scores for each reviewer showed no significant differences between the two techniques., Conclusions: This study demonstrated that pulse sequence parameter optimization can significantly reduce distortion artifact from titanium applicators while maintaining image quality and reasonable imaging times., (Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.)

Purpose: The purpose of this study was to report early outcomes and assess the learning curve in a new MRI-based cervical brachytherapy program., Methods: We accrued 33 patients prospectively, and only patients with ≥3 months' followup (n = 27) were assessed for disease control and toxicity. Eras were defined as first half and second half for the intracavitary (IC)-only era (n = 13 each), and the intracavitary/interstitial (IC/IS) era was separated by difference in applicator availability (n = 7). Dose to 90% of the high-risk clinical target volume (D 90 HR-CTV) and minimum dose to the maximally irradiated 2 cubic centimeters (D 2cc ) to organs at risk were used to assess dosimetry. Statistics were performed with t tests and Kaplan-Meier method., Results: Median followup was 14.7 months. Median treatment duration was 50.5 vs. 57 days for patients treated with external beam radiation therapy at our institution vs. an outside institution (p = 0.03). One-year local control, noncervical pelvic control, distant metastasis-free rate, and overall survival were 84.0%, 96.0%, 78.5%, and 91.3%, respectively. When comparing the first half and second half eras of IC only, there were no differences in median D 90 HR-CTV or D 2cc of the bladder, rectum, or sigmoid. Comparing the entire IC era to the IC/IS era, median D 90 HR-CTV trended higher from 88.0 Gy to 92.9 Gy (p = 0.11). D 2cc rectum decreased from 69.3 Gy to 62.6 Gy (p = 0.01), and D 2cc bladder trended lower from 87.5 Gy to 83.6 Gy (p = 0.09)., Conclusions: There was no significant difference between the first half and second half eras with IC-only MRI-based brachytherapy. Incorporation of an IC/IS applicator generated the greatest dosimetric improvement. Early results of the MRI-based brachytherapy program are favorable., (Published by Elsevier Inc.)

Purpose: To evaluate the dosimetric benefits of MRI-based brachytherapy in small and large high-risk clinical target volume (HR-CTV) in cervical cancer., Methods and Materials: 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 D 90 . 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. D 0.1 cc , D 2 cc , and International Commission of Radiation Unit and Measurements (ICRU) points were used to compare Point A vs. HR-CTV D 90 plans for bladder, rectum, and sigmoid., Results: In the small lesion group, Point A plans vs. HR-CTV D 90 plans had significantly higher D 0.1 cc , D 2 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 HR-CTV D 90 plans for D 0.1 cc , D 2 cc , and ICRU points to the organs at risk (OARs)., Conclusions: The dosimetric advantages to OARs offered by MRI-based brachytherapy with prescription to HR-CTV D 90 compared to Point A is most distinct for patients with smaller HR-CTV (<25 cm 3 ). This study demonstrates sufficient tumor coverage with lower doses to OARs in HR-CTV D 90 vs. Point A plans in the small lesion group. These improvements were not seen in the large lesion group, indicating a lesser dosimetric advantage of HR-CTV D 90 compared to Point A planning when the cervical lesion is >25 cm 3 . Incorporation of interstitial needles for patients with larger HR-CTV is likely the best method to decrease dose to OARs and improve tumor coverage., (Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.)