Volume-based pulsed-dose-rate brachytherapy boosting concurrent chemoradiation as a definitive treatment modality in cervical cancer

PurposeTo report the treatment outcomes and treatment-induced adverse events (AEs) of concomitant chemoradiotherapy boosted with pulsed-dose-rate brachytherapy using volume-based two-dimensional planning in patients with cervical cancer.Patients and MethodsAfter obtaining the institutional review board approval, patients with FIGO Stages IB to IIIB cervical cancer, treated from January 2006 to December 2008 consecutively, were included. Volume-based planning was used and entailed defining an envelope around the tumor on a two-dimensional image and prescribing the dose to this envelope and reporting the dose of the isodose of 60 Gy. Patients and tumor characteristics, dosimetric parameters, AEs and treatment outcomes, local control rate, distant metastases rate, progression-free survival, and overall survival are reported.ResultsThe study included 95 patients; the median age is 50 years. The median tumor size is 50 cc (range, 25–78 cc). Median brachytherapy dose delivered to the envelope is 20 Gy (range, 15–35 Gy), and median volume encompassed by 60 Gy isodose curve is 137 cc (range, 26–365 cc). The 3-year overall survival, progression-free survival, local control rate, and distant metastases rate were 83.8%, 72.4%, 84.8%, and 15.4%, respectively. Gastrointestinal and genitourinary Grade 3 and 4 acute AEs were reported in 11.6% and 3.3% and chronic Grade 3 and 4 AEs were reported in 3.2% and 4.2% of all patients, respectively.ConclusionsChemoradiotherapy followed by pulsed-dose-rate brachytherapy boost is effective and tolerable treatment modality for locally confined cervical cancer.     

Proficiency-based cervical cancer brachytherapy training

PurposeAlthough brachytherapy increases the local control rate for cervical cancer, there has been a progressive decline in its use. Furthermore, the training among residency programs for gynecologic brachytherapy varies considerably, with some residents receiving little to no training. This trend is especially concerning given the association between poor applicator placement and decline in local control. Considering the success of proficiency-based training in other procedural specialties, we developed and implemented a proficiency-based cervical brachytherapy training curriculum for our residents.Methods and MaterialsEach resident placed tandem and ovoid applicators with attending guidance and again alone 2 weeks later using a pelvic model that was modified to allow for cervical brachytherapy. Plain films were taken of the pelvic model, and applicator placement quality was evaluated. Other evaluated metrics included retention of key procedural details, the time taken for each procedure and presession and postsession surveys to assess confidence.ResultsDuring the initial session, residents on average met 4.5 of 5 placement criteria, which improved to 5 the second session. On average, residents were able to remember 7.6 of the 8 key procedural steps. Execution time decreased by an average of 10.5%. Resident confidence with the procedure improved dramatically, from 2.6 to 4.6 of 5. Residents who had previously never performed a tandem and ovoid procedure showed greater improvements in these criteria than those who had. All residents strongly agreed that the training was helpful and wanted to participate again the following year.ConclusionsResidents participating in this simulation training had measurable improvements in the time to perform the procedure, applicator placement quality, and confidence. This curriculum is easy to implement and is of great value for training residents, and would be particularly beneficial in programs with low volume of cervical brachytherapy cases. Simulation programs could also be created for other technically challenging radiation oncology procedures.     

Comparative analysis of rectal dose parameters in image-guided high-dose-rate brachytherapy for cervical cancer with and without a rectal retractor

PurposeThe objective of this study was to determine if use of a rectal retractor (RR) in high-dose-rate intracavitary brachytherapy for cervical cancer reduces rectal dose parameters.Methods and MaterialsWe reviewed data obtained from patients treated with intracavitary brachytherapy for cervical cancer with and without an RR. Treatment plans for each brachytherapy fraction were separated into two groups; R group with use of an RR and P group with use of vaginal packing. Dose–volume parameters for high-risk clinical target volume (HR-CTV), rectum, sigmoid, small bowel, and vaginal surface were collected for each fraction. Rectal D_2cc and International Commission on Radiation Units & Measurements (ICRU) rectal point doses were compared between groups using Student's t tests. Predictors of higher rectal D_2cc were determined by univariate and multivariate regression analyses.ResultsFour hundred sixty-three brachytherapy fractions from 114 patients were used for analysis, 377 fractions with a RR (R group) and 86 with vaginal packing only (P group). Both groups were similar except for slightly higher mean HR-CTV and mean bladder volume in P group. Both mean ICRU rectal point dose (241.1 vs. 269.9 cGy, p = 0.006) and rectal D_2cc (240.6 vs. 283.6 cGy, p < 0.001) were significantly higher in P group. Point A dose, HR-CTV, stage, and use of an RR were significant predictors of rectal D_2cc on multivariate analysis.ConclusionsOur data show that use of an RR leads to lower rectal dose parameters compared with vaginal packing. Further study is needed to determine if this will lead to less long-term toxicity.     

Vaginal cuff brachytherapy in the adjuvant setting for patients with high-risk early-stage cervical cancer

PurposeTo evaluate local control and survival of high-risk patients with early-stage cervical cancer submitted or not to vaginal cuff brachytherapy in the postoperative setting.Methods and MaterialsIn this retrospective cohort of patients treated from 2010 to 2017, patients were eligible if they had confirmed histological diagnosis of cervical cancer treated with surgery and adjuvant radiotherapy with or without chemotherapy. Vaginal cuff brachytherapy (VCB) was indicated according to the radiation oncologist discretion.ResultsSeventy-nine patients were selected, with a median age at diagnosis of 47.5 years (26–77). Brachytherapy was delivered to 59 patients (74.7%). There were no significant differences between the VCB and the no-VCB groups. A total of 13 (16.5%) patients presented one or more events, 5 (25%) and 8 (13.5%) events in the no-VCB and VCB group, respectively. Most recurrences were pelvic and/or vaginal: 7/20 (35%) in the no-VCB group and 9/59 (10.2%) in the VCB group. There were eight systemic relapses with eight deaths. With a median followup of 45 months, mean overall survival and disease-free survival were, respectively, 85.1 and 83.8 months. No variables were correlated with overall survival. The only factor positively correlated to disease-free survival was VCB, with a mean of 86.9 and 68.4 months for patients who did and did not receive brachytherapy, respectively (p = 0.043). Vaginal recurrence was lower in the brachytherapy group, but with no statistical significance (p = 0.065).ConclusionVCB was associated with a reduced recurrence rate in the postoperative setting of high-risk patients with early-stage cervical cancer.     

The 100 most cited articles in cervical cancer brachytherapy

PurposeThis study aimed to identify the 100 most cited research articles on cervical cancer brachytherapy.Methods and MaterialsThe Institute for Scientific Information Web of Science was used to identify the 100 most cited articles in cervical cancer brachytherapy as of July 5, 2019. The following important information was extracted: journal, year and month, country of region, author, type of article, type of dose rate, type of radionuclide, and image modality for brachytherapy planning.ResultsThe 100 most cited articles in cervical cancer brachytherapy were published between 1981 and 2016, and the citations ranged from 858 to 49, which collectively had been cited 11,372 times at the time of searching. The index of citations per year ranged from 63.56 to 1.43. These articles were from 16 countries or regions, with most publications being from the United States (n = 27), followed by Austria (n = 26), Japan (n = 10), France (n = 7), and the Netherlands (n = 7). The International Journal of Radiation Oncology, Biology, Physics produced the most articles (n = 46), followed by Radiotherapy and Oncology (n = 39) and Gynecologic Oncology (n = 5). These articles were categorized as original studies (n = 75), reviews (n = 2), editorials (n = 2), surveys (n = 2), guidelines (n = 3), and recommendations (n = 6). A high dose rate (n = 69) was the most widely used, dose rate followed by a low dose rate (n = 20) and pulsed dose rate (n = 16).ConclusionsThe bibliometric analysis presents a detailed list of the 100 most cited articles in cervical cancer brachytherapy. This analysis provides an insight into historical developments and enables the important advances in this field to be recognized.     

Impact of CT-based brachytherapy in elderly patients with cervical cancer

PurposeThree-dimensional image-guided brachytherapy (3D-IGBT) has become the standard therapy for patients with cervical cancer. However, in this population, the impact of 3D-IGBT in elderly individuals remains unknown. This study assessed the efficacy of 3D-IGBT for elderly patients with cervical cancer.Methods and MaterialsWe performed a retrospective chart review of 105 consecutive patients with cervical squamous cell carcinoma aged ≥70 years who received radiotherapy alone between January 2001 and September 2014. All patients were treated with external beam radiotherapy and high-dose-rate intracavitary brachytherapy. We assessed the treatment outcomes in all patients. We then compared outcomes between two groups: patients treated by changing the Point A dose at brachytherapy (Group A, n = 71) and those treated with 3D-IGBT at least twice (Group B, n = 34).ResultsThe median followup period was 59 (range, 6–203) months; the median age was 77 years. The 5-year local control and cause-specific survival rates were 89% and 78%, respectively. The 5-year cumulative rates of late toxicities of the rectum and bladder of Grade ≥3 were 2.0% and 4.2%, respectively. No statistically significant differences were observed in the local control and cause-specific survival rates, or in the incidence of rectal toxicities between groups. The 3-year cumulative rates of urinary toxicity of Grade ≥1 were 20.4% and 6.9% in Group A and Group B, respectively (p = 0.035).ConclusionIn elderly patients with cervical cancer, 3D-IGBT could be performed safely and effectively and contributed to decreasing urinary toxicity incidence rates.     

Effect of brachytherapy technique and patient characteristics on cervical cancer implant dosimetry

Our purpose was to evaluate the relationship between brachytherapy technique and patient characteristics on dose to organs-at-risk (OARs) in patients undergoing high dose rate (HDR) brachytherapy for cervical cancer. From 1998 to 2008, 31 patients with cervical cancer with full dosimetric data were identified who received definitive external-beam radiation and HDR brachytherapy with tandem and ovoid applicators. Doses were recorded at point A, the International Commission on Radiation Units and Measurements (ICRU)-38 rectal point, the ICRU-38 bladder point, the vaginal surface, and the pelvic sidewall. Generalized estimating equations were used to determine the significance of changes in OAR to point A dose ratios with differences in brachytherapy technique or patient characteristics. Patients underwent a median of 5 brachytherapy procedures (range, 3 to 5), with a total of 179 procedures for 31 patients. For all brachytherapy treatments, the average ratios between the doses for the rectal, bladder, vaginal surface, and pelvic sidewall reference points to those at point A were 0.49, 0.59, 1.15, and 0.17, respectively. In general, decreased OAR dose was associated with a lower stage, younger age, increased ovoid size, increased tandem length, and earlier implant number. Increased tandem curvature significantly increased bladder dose and decreased rectal dose. Intravenous anesthesia usage was not correlated with improved dosimetry. This study allowed identification of patient and procedure characteristics influencing OAR dosing. Although the advent of 3-dimensional (3D) image-guided brachytherapy will bring new advances in treatment optimization, the actual technique involved at the time of the brachytherapy implant procedure will remain important.     

Simulation-based graduate medical education in MR-guided brachytherapy for cervical cancer

PurposeBrachytherapy is critical for the curative treatment of locally advanced cervical cancer. Although brachytherapy use is declining in the United States (U.S.), novel interstitial or intracavitary applicators and advances in image guidance for applicator placement and treatment planning have allowed for tumor dose escalation while reducing normal tissue toxicity. Recent survey data have suggested insufficient brachytherapy training for radiation oncology trainees in the United States. This study aimed to address these gaps by developing and piloting a simulation-based education (SBE) workshop for MR-guided cervical cancer brachytherapy.Methods and MaterialsAn SBE workshop was developed for graduate medical education (GME) trainees focusing on MR-guided brachytherapy for cervical cancer. Four hands-on stations, simulating aspects of the procedure, were led by a team of gynecological brachytherapy experts. The learners were radiation oncology residents and fellows in a U.S. GME training program. The primary outcome was feasibility, assessed by completion of the workshop within the time constraints of the curriculum. Learners completed preworkshop and postworkshop surveys to provide information on efficacy.ResultsThe workshop was successfully completed in a 1-h block of GME didactic time. Ten trainees completed all four stations, and all completed preworkshop and postworkshop surveys, which showed improvements in knowledge and technical proficiency. Feedback was positive, and trainees requested additional learning opportunities.ConclusionsThis study showed that GME-focused SBE in MR-guided cervical cancer brachytherapy was feasible. SBE provided a nonclinical environment in which to practice aspects of MR-guided brachytherapy. Ongoing work includes collaboration with other U.S. institutions. Future studies should focus on international adaptation.     

宫颈癌近距离放射治疗阴道不良反应与剂量效应关系

近距离放射治疗是宫颈癌根治性放射治疗和术后放射治疗不可替代的重要组成部分。阴道与宫颈相邻的解剖位置关系以及阴道施源器放置于膀胱和直肠之间的阴道内,决定了阴道吸收剂量极度不均匀和难以评估。本文综述了宫颈癌近距离放射治疗中阴道不良反应发生情况、阴道剂量评估方法、剂量不良反应相关性和剂量限值,以期为宫颈癌近距离放射治疗的临床实践提供一定借鉴。     

Impact of suboptimal tandem implantation on local control and complications in intracavitary brachytherapy for cervix cancer

PURPOSECorrect tandem implantation for cervix cancer intracavitary brachytherapy may be challenging. We investigated whether suboptimal implantation can be related to patient and disease characteristics and may result in subsequent underutilization of brachytherapy in cervical cancer.METHODS AND MATERIALSConsecutive cervix cancer patients referred for intracavitary brachytherapy after external beam radiation therapy performed in several general hospitals from 2013 to 2017 were included.ResultsIn 172 patients having 301 procedures, 95 implantations were suboptimal (15% inadequate tandem insertions, 10% subserosal insertion, and 6% uterine perforation on postimplant CT scan). Risk factors were age, myometrium invasion, and uterine retroversion. Median followup was 21 months. Three-year local control and survival rates were 72% and 85%, respectively. Forty-seven patients (27%) failed to receive brachytherapy. Failure to perform brachytherapy was associated with poorer local control (OR = 0.34 [0.17–0.67], p = 0.001). By contrast, suboptimal implantation did not increase local failure or toxicity rates in patients undergoing brachytherapy. No peritoneal carcinomatosis occurred after uterine perforation in our cohort.CONCLUSIONSSuboptimal implantation was frequent. In the absence of image guidance during implantation, conversion to other treatment modalities (including external beam radiation therapy) due to insertion difficulties resulted in worse local control. With optimization, however, suboptimal brachytherapy implantation did not result in suboptimal dose coverage or poorer local control. Failure to perform a brachytherapy boost correlates with increased local failure risk in patients with cervix cancer, whereas tandem malposition does not. Real-time intraoperative ultrasound guidance may be useful to reduce uterine perforation rates and thus increase brachytherapy use.     

形变配准在宫颈癌近距离放疗分次间剂量评估中的可行性研究

目的:比较近距离放疗分次间靶区和正常组织在形变配准(DIR)和简单累加剂量体积直方图(DVH)情况下,累积剂量的剂量学差异,分析在宫颈癌三维近距离放疗计划中,形变配准技术应用于靶区和正常组织剂量评估的可行性。方法:回顾性选取13例宫颈癌近距离放疗病例,每个病例均进行了4次CT定位的近距离放疗。对每个病例的4次CT进行形...     

Comparison of clinical outcomes achieved with image-guided adaptive brachytherapy for cervix cancer using CT or transabdominal ultrasound

PurposeThis study aimed to evaluate retrospectively the treatment results when using various image-guided adaptive brachytherapy treatments for cervical cancer treated by radical radiotherapy.Methods and MaterialsFrom 2014 to 2017, 188 patients with cervical carcinoma were treated by whole pelvic radiotherapy plus four fractions of image-guided brachytherapy. Eight patients were excluded because of missing data. Consequently, 180 patients were analyzed. Of 180 patients, 92 were treated by CT-based brachytherapy (CT-BT), and transabdominal ultrasound–based brachytherapy (TAUS-BT) was used to treat another group. The treatment results and toxicity outcomes were evaluated by comparing the image-guidance techniques.ResultsThe mean follow-up time was 32 months (interquartile range 29.5–42 months). The mean age was 57 years (interquartile range from 50 to 65 years). In the CT-BT group, the mean cumulative doses to high-risk clinical target volume, bladder, rectum, and sigmoid were 87.2 Gy, 84.0 Gy, 68.8 Gy, and 69.8 Gy, respectively. In the TAUS-BT group, the mean cumulative doses to the cervix reference, bladder, and rectum points were 84.0 Gy, 65.5 Gy, and 74.0 Gy, respectively. There were no differences in the 2-year local control rate (p = 0.88) and disease-free survival rate (p = 0.34) in both groups. No difference in gastrointestinal and genitourinary toxicity was observed in both groups, but there was higher vaginal toxicity in the TAUS-BT group compared with the CT-BT group (p = 0.03).ConclusionsNo difference in treatment results was observed between CT-based and TAUS-based approaches. However, TAUS-BT had higher vaginal toxicity in our retrospective analysis.     

Implant time and process efficiency for CT-guided high-dose-rate brachytherapy for cervical cancer

PurposeThis investigation details the time and teamwork required for CT-guided tandem and ring high-dose-rate brachytherapy.Methods and MaterialsFrom 2010 to 2012, 217 consecutive implantations were identified on 52 patients. We gathered key workflow times: preoperative, applicator insertion, CT image, treatment planning, treatment, patient recovery, and total time in clinic. Linear fixed-effects models were used, and key workflow times were the outcome variables and factors including age, body mass index, stage, outside referral, number of implant per patient, number of implants per day, and year of implantation were examined as fixed effects.ResultsOf the 52 patients, 62% of the patients were Fédération Internationale de Gynécologie et d'Obstétrique Stage 2B, 88% were treated with concurrent chemotherapy, and 23% were treated at an outside facility and referred for the procedure. The mean times (minutes) for each step were as follows: preoperative evaluation, 93; insertion, 23; imaging, 45; treatment planning, 137; treatment, removal, and recovery, 115; total clinic time, 401. For the insertion time, the greater implant number per patient was significantly associated with a decreased total insertion time, with and without adjusting for other covariates, p = 0.002 and p = 0.0005, respectively. Treatment planning time was expedited with increasing number of implant per patient and comparing treatment times in 2012 with those in 2010, p = 0.01 and p < 0.0001, respectively.ConclusionsGynecologic brachytherapy requires a skillfully coordinated and efficient team approach. Identifying critical components and the time required for each step in the process is needed to improve the safety and efficiency of brachytherapy. Continuous efforts should be made to enhance the optimal treatment delivery in high-dose-rate gynecologic brachytherapy.     

Impact of marital status on receipt of brachytherapy and survival outcomes in locally advanced cervical cancer

PurposeMarriage has been associated with enhanced survival among cancer patients, but conflicting correlations have been suggested in cervical cancer. We assessed the impact of marital status on receipt of brachytherapy and survival in women with locally advanced cervical cancer.Methods and MaterialsThree thousand, eight hundred and twelve patients with Stage IB2–IVA cervical cancer diagnosed from 2006 to 2015 treated with external beam radiotherapy were identified from the California Cancer Registry. Chi-square tests were used to compare patient characteristics by marital status and boost type. The association of marital status with brachytherapy (BT) receipt was assessed using multiple logistic regression. Fine and Gray competing risks and Cox proportional hazards regressions were used to estimate cervical cancer–specific survival (CCSS) and overall survival (OS), respectively.ResultsMost women were unmarried (58.8%). Half (50.4%) received BT, while 33.1% received no boost; most (86.3%) received chemotherapy. Unmarried women had similar odds of receiving BT as married women (OR = 1.07, 95% CI: 0.90-1.28, p = 0.4370) but were less likely to receive chemotherapy (84.3% vs. 89.1%, p < 0.0001). Singlehood was significantly associated with worse CCSS (subdistribution hazard ratio = 1.21, 95% CI: 1.03-1.42, p < 0.0174) and OS (hazard ratio = 1.18, 95% CI: 1.03-1.36, p < 0.0153). Not receiving a radiation boost was also significantly associated with worse CCSS (subdistribution hazard ratio = 1.21, 95% CI: 1.02-1.43, p = 0.0317) and OS (hazard ratio = 1.21, 95% CI: 1.05-1.40, p = 0.0100).ConclusionsThere were no differences in BT receipt in married vs. unmarried patients. However, unmarried patients had worse CCSS and OS and were less likely to receive chemotherapy. Interventions targeting social factors are needed to improve outcomes in this vulnerable population.     

局部晚期宫颈癌腔内放疗联合组织间插植的剂量学研究

目的 比较局部晚期宫颈癌单纯腔内放疗与腔内联合组织间插植放疗的剂量学差异。方法 2016年5月—2017年3月局部晚期宫颈癌患者共35例,均行根治性放疗,治疗方法为外照射+腔内联合组织间插植放疗。调强放射治疗处方剂量为46.8~50.4 Gy/26~28次,1.8 Gy/次。腔内联合组织间插植放疗剂量为7 Gy/次,1次/周,共4次。同一患者首先置入三管式后装放疗施源器,采集CT图像制定治疗计划,取出三管式施源器后,置入宫腔管并植入插植针,再次采集图像制定放疗计划。分别评价比较两组计划中靶区及危及器官的受照剂量差别。结果 共制定212次后装放疗计划,其中单纯腔内治疗计划106例,腔内联合组织间插植治疗计划106例。腔内联合组织间插植放疗组计划较单纯腔内放疗组的靶区剂量明显升高,高危临床靶区（CTV）的D₉₀、中危CTV的D₉₀均显著增高（t=-6.01、-2.73,P<0.05）,膀胱、直肠、乙状结肠的D_{2 cm³}显著降低（t=3.07、4.52、2.91,P<0.05）。结论 局部晚期宫颈癌应用腔内联合插植放疗可以明显提高靶区剂量,并降低危及器官膀胱、直肠和乙状结肠的受照剂量。     

Comparison of spinal and general anesthesia approaches for MRI-guided brachytherapy for cervical cancer

PurposeTo evaluate the impact of general versus spinal anesthesia on postprocedure narcotic use and of extradepartmental planning MRI on treatment time in high-dose-rate brachytherapy for cervical cancer.Methods and MaterialsTwenty-five patients (10 general anesthesia and 15 spinal anesthesia) who collectively received 96 brachytherapy fractions (39 general and 57 spinal) for cervical cancer between February 2015 and April 2017 were retrospectively reviewed. Over this time, institutional practice shifted from operating room–based general anesthesia to intradepartmental spinal anesthesia for tandem and ring placement. In some cases, extradepartmental planning MRI was performed. Administrations of narcotics after tandem and ring placement were recorded, and dosages were converted to intravenous (IV) morphine equivalents. Total treatment times for fractions using spinal anesthesia were documented.ResultsThe general anesthesia group included a significantly higher proportion of fractions using postprocedure narcotics (100.0% vs. 31.6%, p < 0.0001). The general and spinal anesthesia groups required an average of 16.9 mg (range: 2.0–59.2) and 1.4 mg (range: 0.0–17.5) IV morphine equivalents per fraction, respectively (p < 0.0001). When using spinal anesthesia, the average total treatment time with MRI was 311.0 min (range: 218–379) versus 306.6 min (range: 177–429) without MRI (p = 0.810).ConclusionIntradepartmental spinal anesthesia results in significant decreases in postprocedure narcotic usage compared with operating room–based general anesthesia. When using spinal anesthesia, addition of extradepartmental MRI does not increase treatment time. This workflow avoids transporting patients under general anesthesia, minimizes the need for MRI-compatible monitoring, allows treatment of multiple patients per day, and provides adequate analgesia.     

Inverse planning simulated annealing for magnetic resonance imaging-based intracavitary high-dose-rate brachytherapy for cervical cancer

PURPOSE: To develop a technique using exclusively magnetic resonance imaging (MRI) to perform dwell position identification, targets and organs at risk delineation, and to apply inverse planning dose optimization to high-dose-rate brachytherapy for cervical cancer. METHODS AND MATERIALS: We included 15 consecutive women treated with high-dose-rate (HDR) brachytherapy for cervical cancer. All patients underwent MRI after placement of tandem and ring applicator containing a gadodiamide-filled dummy marker. This technique allowed direct visualization of the source pathway and precise definition of the intra-applicator source positions. For each patient, we delineated gross target volume (GTV), high-risk clinical target volume (HR-CTV), and organs at risk on MRI, according to the European Gynecological GEC-ESTRO Working Group definitions. We performed inverse planning simulated annealing (IPSA) and analyzed the dose-volume histograms with the following endpoints: D(90), D(100), and V(100) for GTV and HR-CTV; D0.1 cc, D1 cc, D2 cc for bladder, rectum, and bowel; and dose at Point A. RESULTS: The intra-applicator source pathway was easily visualized on MRI using the gadodiamide-filled marker. IPSA provided excellent target coverage. The mean D(90) and V(100) for HR-CTV were 103+/-5% and 92+/-3%, respectively. IPSA provided excellent bladder sparing. D1 cc and D2 cc of bladder were 73+/-10% and 67+/-10%, respectively. CONCLUSIONS: We developed a novel technique that allows direct visualization of the intra-applicator source pathway on MRI. Using this technique, we successfully performed inverse planning directly from MRI.     

Patient-reported sexual adjustment after definitive chemoradiation and MR-guided brachytherapy for cervical cancer

Purpose

The treatment of locally advanced cervical cancer with definitive chemoradiation (CRT) is associated with vaginal toxicity and altered sexual satisfaction. This prospective study assessed patient-reported sexual adjustment, vaginal dosimetry, and physician-reported vaginal toxicity in patients with cervical cancer treated with CRT and MR-guided brachytherapy (BT).

基于3D U-net的宫颈癌近距离治疗剂量分布预测

目的 基于三维（3D） U-net深度学习模型,建立预测CT引导下宫颈癌近距离治疗计划的3D空间剂量分布。方法 2021年4-9月收集114例宫颈癌患者三维近距离放疗计划（处方剂量6 Gy）组成数据集,按84 ∶11 ∶19划分为训练集、验证集、测试集。利用3D U-net模型进行500次（epoch）训练,分别评估测试集病例体素级的平均剂量偏差（MDD）与绝对剂量偏差（MADD）、等剂量面包围体积的戴斯系数（DSC）、处方剂量适形度指数（CI）、高危临床靶区（HRCTV）的D₉₀和平均剂量D_mean、膀胱、直肠、小肠、结肠的D_{1 cm³}与D_{2 cm³}剂量学参数。结果 测试集中19例患者的3D剂量矩阵MDD与MADD分别为-0.01±0.03和（0.04±0.01） Gy。50%到150%处方剂量的DSC在0.89到0.94之间,处方剂量CI为0.70±0.04。HRCTV的D₉₀的平均偏差为2.22%,D_mean的偏差为-4.30%。膀胱、直肠、小肠、结肠的D_{1 cm³}与D_{2 cm³}最大偏差分别为2.46%和2.58%。模型预测平均耗时2.5 s。结论 本研究实现了一种基于3D U-net的预测宫颈癌3D剂量分布的深度学习模型,为宫颈癌近距离治疗自动化设计奠定基础。