ABSTRACT
Objective:Topredict the three-dimensional dose distribution of regions of interest (ROI) with brachytherapy for cervical cancer based on U-Net fully convolutional network, and evaluate the accuracy of prediction model.Methods:First, 100 cases of cervical cancer intracavity combined with interstitial implantation were selected as the entire research data set, and divided into the training set ( n=72), validation set ( n=8), and test set ( n=20). Then the U-Net was used to construct two models based on whether the uterine tandem and the implantation needles were included as the distinguishing factors. Finally, dose distribution of 20 cases in the test set were predicted using the trained model, and comparative analysis was performed. The performance of the model was jointly evaluated by , and the mean absolute deviation (MAD). Results:Compared with the model without the uterine tandem and the implantation needles, the of the rectum was increased by (16.83±1.82) cGy ( P<0.05), and the or of the other ROI were not different significantly (all P>0.05). The MAD of the high-risk clinical target volume, rectum, sigmoid, small bowel, and bladder was increased by (11.96±3.78) cGy, (11.43±0.54) cGy, (24.08±1.65) cGy, (17.04±7.17) cGy and (9.52±4.35) cGy, respectively (all P<0.05). The MAD of the intermediate-risk clinical target volume was decreased by (120.85±29.78) cGy ( P<0.05). The mean value of MAD for all ROI was decreased by (7.8±53) cGy ( P<0.05), which was closer to the actual plan. Conclusions:U-Net fully convolutional network can be used to predict three-dimensional dose distribution of patients with cervical cancer undergoing brachytherapy. Combining the uterine tube with the implantation needles as the input parameters yields more accurate predictions than a single use of the ROI structure as the input.
ABSTRACT
Objective:To assess the feasibility of deformable image registration (DIR) in evaluating cumulative dose distribution of bladder and rectum of cervical cancer patients during helical tomotherapy (HT)-based intensity-modulated radiotherapy (IMRT) and high-dose-rate(HDR) brachytherapy.Methods:Clinical data of 18 patients were retrospectively analyzed. Cumulative bladder/rectum D 2cm 3 and high-risk clinical target volume (HR-CTV) D 90% parameters were calculated and compared to two direct parameter-adding methods with two registration-adding methods. Equivalent uniform dose (EUD group) and overlapping high dose (OHD group) methods were employed as parameter-adding methods. The registration-adding methods including rigid image registration (RIR group) and deformable image registration (DIR group) were adopted based on a commercial image registration software (MIM Maestro ?). The dice similarity coefficient (DSC) and mean distance to agreement (MDA) were measured to assess the accuracy of RIR and DIR. Results:In the EUD, OHD, RIR and DIR groups, the cumulative doses of bladder/rectum D 2cm 3 and HR-CTV D 90% were (80.11±3.59) Gy (EQD 2Gy), (82.23±3.46) Gy (EQD 2Gy), (80.99±6.01) Gy (EQD 2Gy) and (81.19±3.11) Gy (EQD 2Gy)( P=0.516); (72.90±3.58) Gy (EQD 2Gy), (73.83±4.28) Gy (EQD 2Gy), (72.45±6.05) Gy (EQD 2Gy) and (71.98±2.89) Gy (EQD 2Gy)( P=0.625), and (85.51±2.91) Gy (EQD 2Gy), (87.65±3.46) Gy (EQD 2Gy), (81.53±3.63) Gy (EQD 2Gy) and (85.81±3.30) Gy (EQD 2Gy)( P<0.001), respectively. The mean DSC of the bladder, rectum and HR-CTV were 0.69, 0.65 and 0.63 with RIR; and 0.85, 0.81 and 0.78 with DIR ( P<0.001), respectively. In DIR, the average MDA of bladder, rectum, and HR-CTV were 2.88, 2.48 and 2.66 mm, respectively. Conclusions:The cumulative DVH parameters among 4 groups show no significant difference in the bladder/rectum D 2cm 3/D 0.2cm 3. Since the DIR group achieves satisfactory volume matching of greater than 0.8 with DSC analysis, it can yield acceptable results for clinical application between HT IMRT and HDR BT for cervical cancer.
ABSTRACT
Objective:To evaluate the difference of dosimetry between three-dimensional and two-dimensional plans based on CT images of occult perforation in brachytherapy of cervical cancer, aiming to provide clinical reference.Methods:A total of 817 patients with cervical cancer received simple intrauterine (intrauterine tandem plus vaginal colpostats) three-dimensional brachytherapy in Chongqing University Cancer Hospital from January 2019 to December 2020 were retrospectively reviewed. Among them, 16 patients had occul uterine perforation. Based on Oncentra Brachy Therapy plan system, the single prescription dose was 6Gy. Three-dimensional (3D group) and two-dimensional (2D group) plans were designed on the perforated CT images The target volume, conformal index (CI), conformal index coformity index (COIN) and organs-at-risk (OAR) D 2cm 3 parameters were used to assess the plans between two groups. Results:The incidence of pccult uterine perforation was 1.96%(16/817) during brachytherapy for cervical cancer. The volume of prescription dose curve in the 3D group was (40.74±14.98) cm 3, significantly smaller compared with (91.46±19.71) cm 3 in the 2D group ( P<0.05), whereas the volume of the high-risk clinical target area wrapped by prescription dose curve did not significantly differ between two groups ( P>0.05). The CI and COIN in the 3D group were 0.79±0.10 and 0.72±0.96, significantly higher compared with 0.38±0.09 and 0.37±0.18 in the 2D group (both P<0.05). The D 2cm 3 of bladder, rectum, sigmoid colon, small intestine in the 3D group were (306.06±77.57) cGy, (252.27±72.60) cGy, (127.25±62.84) cGy and (228.79±94.90) cGy, significantly lower than (548.03±164.21) cGy, (411.16±118.74) cGy, (227.45±94.48) cGy and (450.95±157.96) cGy in the 2D group (all P<0.05). Conclusions:Application of image guidance in brachytherapy of cervical cancer is helpful to detect occult uterine perforation. When occult uterine perforation occurs, the use of three-dimensional plan can basically meet the clinical needs, which is significantly better than the two-dimensional plan.
ABSTRACT
Brachytherapy is an integral part of radiotherapy treatment for cervical cancer. With the rapid development of medical imaging technology, three-dimensional (3D) imaging modality has been applied in the brachytherapy for cervical cancer. After computed tomography (CT) and magnetic resonance imaging (MRI), 3D ultrasound has been gradually applied to guide the brachytherapy for cervical cancer due to its superior soft tissue imaging characteristics, economy, high efficiency and convenience. In this article, the research progress on the application of ultrasonography in brachytherapy was summarized according to literature review, aiming to provide reference for subsequent research.
ABSTRACT
Objective To compare the dosimetric differences between free-hand method and virtually optimized method for implanting needles in intracavitary and interstitial combined brachytherapy (IC/IS BT) of cervical cancer,and to explore the improvement space of the existing interstitial brahcytherapy plan.Methods High-dose-rate cervical cancer IC/IS BT plans (short for Treatment-Plan) of 18 cases were retrospectively analyzed.For each treatment plan,Nucletron Oncentra 3D brachytherapy planning system was utilized to redesign the virtually optimized insertion method IC/IS BT plan (short for Optimized-Plan).Dose volume histogram was adopted to evaluate the dose distribution in high-risk clinical target areas and exposure dose to organ at risk (OAR).The plan execution efficiency between two plans was also assessed.Results Comparing these two plans,the differences in conformity and uniformity of dose distribution of the target area were statistically significant (P=0.000,0.008).The differences of D0.01 cm3,D1 cm3,D2 cm3 and D5 cm3 in bladder,rectum,sigmoid and small bowel were all statistically significant (all P＜0.05).Optimized-Plan could reduce the D2 cm3 of bladder,rectum,sigmoid and small bowel by 60.41,36.43,27.53 and 12.43 cGy,respectively.The execution time for the Treatment-Plan and Optimized-Plan were (857.92±243.39) s and (804.53±239.13) s with statistical significance (P＜0.001).Conclusions Compared with the free-hand method,virtually optimized method yields more conformable coverage of the target area and more uniform dose distribution.At the same time,the doses of each OAR are reduced to different degrees and the execution time of the plan is also shortened.
ABSTRACT
Brachytherapy is an integral part of radiotherapy treatment for cervical cancer.With the rapid development of medical imaging technology,three-dimensional (3D) imaging modality has been applied in the brachytherapy for cervical cancer.After computed tomography (CT) and magnetic resonance imaging (MRI),3D ultrasound has been gradually applied to guide the brachytherapy for cervical cancer due to its superior soft tissue imaging characteristics,economy,high efficiency and convenience.In this article,the research progress on the application of ultrasonography in brachytherapy was summarized according to literature review,aiming to provide reference for subsequent research.
ABSTRACT
Brachytherapy plays a key role in the radical radiotherapy of cervical cancer.The time concept was introduced in the 3D brachytherapy according to ICRU report No.89 for cervical cancer treatment.4D brachtherapy,as an adaptive brachytherapy,was formally proposed in this report.In this article,relevant data were searched based on ICRU report No.89 combined with the experience in our center to analyze,summarize and conclude the chapters related to target contouring,aiming to provide evidence for the colleagues who perform the brachytherapy in patients with cervical cancer.
ABSTRACT
Radiotherapy is an important part of the postoperative adjuvant therapy of cervical cancer. Along with the persistent development of radiotherapy techniques, the application of brachytherapy has been more and more used as a boost to external beam radiotherapy. In this artical, the indications of postoperative radiotherapy and the application of brachytherapy were reviewed.
ABSTRACT
Radiotherapy is an important part of the postoperative adjuvant therapy of cervical cancer.Along with the persistent development of radiotherapy techniques,the application of brachytherapy has been more and more used as a boost to external beam radiotherapy.In this artical,the indications of postoperative radiotherapy and the application of brachytherapy were reviewed.
ABSTRACT
Objective To investigate the clinical outcomes of patients with locally advanced uterine cervical cancer (UCC) treated by 3-dimensional high dose rate-intracavitary brachytherapy (3D HDR-ICBT) combined with complementary applicator-guided external beam radiotherapy (EBRT).Methods A total of 120 patients pathologically diagnosed with locally advanced UCC (tumors with a maximum diameter≥6 cm or ≥5 cm complicated with eccentric tumor growth) treated with concurrent chemoradiotherapy (CCRT) from June 2010 to June 2015 were recruited.Five fractions of 3D HDR-ICBT combined with complementary applicator-guided external beam radiotherapy were performed.The prescribed dose for HR-CTV and IR-CTV was 7 Gy (D9o) and 5-6 Gy (D90).The rectum,sigmoid colon,bladder and adjacent small intestine were delineated as the organs at risk.Intensity-modulated radiation therapy (IMRT) was used for EBRT (45 Gy/ 25f) combined with cisplatin-based chemotherapy every three weeks (75 mg/m2).Results The median follow-up time was 46 months (14-96 months).The 5-year local control rate (LCR),disease-free survival (DFS),and overall survival (OS) were 92.8％,76.6％ and 81.0％,respectively.The incidence rate of grade Ⅰ-Ⅱ genitourinary and gastrointestinal acute toxicities were 57.8％ and 14.6％,whereas 8.1％ and 2.9％ for grade Ⅲ toxicities.The incidence rate of later grade Ⅰ-Ⅱ genitourinary and gastrointestinal toxicities were 8.4％ and 5.3％,and 0.97％ and 1.3％ for grade Ⅲ late toxicities.Conclusions The combination of HDR-ICBT with an applicator-guided IMRT (ICBT+IMRT) yields low incidence of severe adverse events,relatively high LC and OS rate for locally advanced UCC.It is an efficacious comprehensive treatment of locally advanced bulky UCC.
ABSTRACT
Brachytherapy is a key part of radical radiotherapy for cervical cancer. Along with the persistent development of radiotherapy techniques, the combined application of brachytherapy and intensity-modulated radiotherapy ( IMRT) has been proposed by scholars for cervical cancer patients presenting with large residual tumors accompanied by parametrial infiltration after IMRT. In this article, recent research progress on IMRT combined with brachytherapy applied in the treatment of cervical cancer was reviewed.
ABSTRACT
Precise implantation of applicator is the key step of brachytherapy in cervical cancer patients. The imaging guidance can guarantee the accuracy of applicator placement. At present, the imaging approaches used to guide the applicator placement mainly include ultrasound, CT and X-ray, and MRI and laparoscopy have been applied in certain institutions. There has been no consensus on the standard imaging technique. In this paper, nearly 50 articles and surveys were reviewed to demonstrate that ultrasound-guided placement is of clinical value and guiding significance. Therefore, the application of ultrasound-guided applicator placement in the brachytherapy for cervical cancer was summarized and reviewed.
ABSTRACT
Objective@#To evaluate whether the self-designed single-channel intracavitary applicator yields equivalent clinical efficacy and safety to the standard Fletcher-type three-channel applicator in the high-dose-rate (HDR) brachytherapy for uterine cervical cancer.@*Methods@#From December 2011 to April 2017, patients initially diagnosed with cervical cancer were randomly assigned into the external beam radiotherapy (EBRT)+ single-channel intracavitary applicator group (the patent single-channel group) and EBRT+ the Fletcher applicator group. Whole pelvis irradiation was delivered with 6-MV photons via a four-field box variant or anterior and posterior parallel fields. Five to six fractions of intracavitary brachytherapy were performed at a dose of 7 Gy at point A once a week after 30 Gy (BED at point A: 80-90 Gy). Chemotherapy was given with intravenous injection of cisplatin at a dose of 40 mg/m2 once weekly during EBRT.Clinical efficacy and safety were evaluated after the treatment.@*Results@#In total, 150 eligible cases were assigned into the Fletcher applicator group and 149 cases into the patent single-channel group. The short-term clinical efficacy and acute toxicity did not significantly differ between two groups. The response rate was 94.0% in the Fletcher group, and 94.7% in the patent single-channel group. In the Fletcher applicator group, 76(50.7%) patients developed ≥ grade 3 hematologic toxicity and 61(40.9%) in the patent group (P=0.195).@*Conclusions@#The self-designed patent single-channel intracavitary applicator yields equivalent clinical efficacy and safety (acute toxicity) to the standard Fletcher-type three-channel applicator in the HDR brachytherapy for uterine cervical cancer.@*Clincal Trial Registration@#Chinese Clinical Trial Registry (ChiCTR-TRC-12002321).