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Gautam S, Osman AFI, Richeson D, Gholami S, Manandhar B, Alam S, Song WY. Attention 3D U-NET for dose distribution prediction of high-dose-rate brachytherapy of cervical cancer: Direction modulated brachytherapy tandem applicator. Med Phys 2024; 51:5593-5603. [PMID: 38830129 DOI: 10.1002/mp.17238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 03/27/2024] [Accepted: 05/21/2024] [Indexed: 06/05/2024] Open
Abstract
BACKGROUND Direction Modulated Brachytherapy (DMBT) enables conformal dose distributions. However, clinicians may face challenges in creating viable treatment plans within a fast-paced clinical setting, especially for a novel technology like DMBT, where cumulative clinical experience is limited. Deep learning-based dose prediction methods have emerged as effective tools for enhancing efficiency. PURPOSE To develop a voxel-wise dose prediction model using an attention-gating mechanism and a 3D UNET for cervical cancer high-dose-rate (HDR) brachytherapy treatment planning with DMBT six-groove tandems with ovoids or ring applicators. METHODS A multi-institutional cohort of 122 retrospective clinical HDR brachytherapy plans treated to a prescription dose in the range of 4.8-7.0 Gy/fraction was used. A DMBT tandem model was constructed and incorporated onto a research version of BrachyVision Treatment Planning System (BV-TPS) as a 3D solid model applicator and retrospectively re-planned all cases by seasoned experts. Those plans were randomly divided into 64:16:20 as training, validating, and testing cohorts, respectively. Data augmentation was applied to the training and validation sets to increase the size by a factor of 4. An attention-gated 3D UNET architecture model was developed to predict full 3D dose distributions based on high-risk clinical target volume (CTVHR) and organs at risk (OARs) contour information. The model was trained using the mean absolute error loss function, Adam optimization algorithm, a learning rate of 0.001, 250 epochs, and a batch size of eight. In addition, a baseline UNET model was trained similarly for comparison. The model performance was evaluated on the testing dataset by analyzing the outcomes in terms of mean dose values and derived dose-volume-histogram indices from 3D dose distributions and comparing the generated dose distributions against the ground-truth dose distributions using dose statistics and clinically meaningful dosimetric indices. RESULTS The proposed attention-gated 3D UNET model showed competitive accuracy in predicting 3D dose distributions that closely resemble the ground-truth dose distributions. The average values of the mean absolute errors were 1.82 ± 29.09 Gy (vs. 6.41 ± 20.16 Gy for a baseline UNET) in CTVHR, 0.89 ± 1.25 Gy (vs. 0.94 ± 3.96 Gy for a baseline UNET) in the bladder, 0.33 ± 0.67 Gy (vs. 0.53 ± 1.66 Gy for a baseline UNET) in the rectum, and 0.55 ± 1.57 Gy (vs. 0.76 ± 2.89 Gy for a baseline UNET) in the sigmoid. The results showed that the mean absolute error (MAE) for the bladder, rectum, and sigmoid were 0.22 ± 1.22 Gy (3.62%) (p = 0.015), 0.21 ± 1.06 Gy (2.20%) (p = 0.172), and -0.03 ± 0.54 Gy (1.13%) (p = 0.774), respectively. The MAE for D90, V100%, and V150% of the CTVHR were 0.46 ± 2.44 Gy (8.14%) (p = 0.018), 0.57 ± 11.25% (5.23%) (p = 0.283), and -0.43 ± 19.36% (4.62%) (p = 0.190), respectively. The proposed model needs less than 5 s to predict a full 3D dose distribution of 64 × 64 × 64 voxels for any new patient plan, thus making it sufficient for near real-time applications and aiding with decision-making in the clinic. CONCLUSIONS Attention gated 3D-UNET model demonstrated a capability in predicting voxel-wise dose prediction, in comparison to 3D UNET, for DMBT intracavitary brachytherapy planning. The proposed model could be used to obtain dose distributions for near real-time decision-making before DMBT planning and quality assurance. This will guide future automated planning, making the workflow more efficient and clinically viable.
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Affiliation(s)
- Suman Gautam
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia, USA
| | | | - Dylan Richeson
- Department of Radiation Oncology, Inova Schar Cancer Institute, Fairfax, Virginia, USA
| | - Somayeh Gholami
- Department of Radiation Oncology, University of Utah, Salt Lake City, Utah, USA
| | - Binod Manandhar
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Sharmin Alam
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - William Y Song
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia, USA
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Romano KD, Petroni G, Ward K, Zheng W, Mistro M, Libby B, McLaughlin C, Showalter TN, Janowski EM. A randomized trial evaluating a novel hydrogel packing system compared to standard packing during image-guided high-dose rate brachytherapy boost for cervical cancer. Brachytherapy 2024; 23:248-256. [PMID: 38519352 PMCID: PMC11098690 DOI: 10.1016/j.brachy.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/02/2024] [Accepted: 02/16/2024] [Indexed: 03/24/2024]
Abstract
INTRODUCTION The purpose of this prospective randomized trial was to compare the use of a novel vaginal hydrogel packing system (BrachyGel) to standard vaginal packing (VP) during high dose rate (HDR) brachytherapy (BT) for locally advanced cervical cancer (LACC). METHODS This cross-over study included LACC patients receiving HDR BT boost (intracavitary +/- interstitial). All patients received alternating gauze or BrachyGel VP on Arms A and B. Patients, physicians, and physicists evaluated BT characteristics via a 4-point Likert scale. Adverse events (AEs) were prospectively collected and scored per CTCAE. RESULTS The 20 patients enrolled. The mean bladder D2cc difference between gauze and BrachyGel in Arm A was 0.117 Gray (Gy) and in Arm B 0.013 Gy. The mean difference in rectum D2cc in Arm A and Arm B was -0.189 Gy and -0.191 Gy, respectively. The mean dose to 90% of the high-risk clinical target volume (HR-CTV) for gauze compared to BrachyGel was -0.032 Gy (95% CI: 0.472, 0.409). Patient-reported discomfort was similar with BrachyGel and gauze ("mild/moderate" 70.0% vs 74.0%, respectively). The clarity of VP was similar between BrachyGel and gauze (86.8% vs 89.7%, respectively). The completeness of VP was more frequently "excellent/good" with BrachyGel (79.0%) compared to gauze (56.4%). The ease of packing was more frequently "extremely easy" with BrachyGel (21.2% vs 0%). No serious AEs were reported. CONCLUSION This randomized trial found no clinically significant difference in OAR or HR-CTV dosimetry between BrachyGel and standard VP. BrachyGel performed well compared to gauze for the patient and physician use experience.
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Affiliation(s)
- Kara D Romano
- Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia, USA.
| | - Gina Petroni
- School of Public Health Sciences, Division of Biostatistics, University of Virginia, Charlottesville, Virginia, USA
| | - Kristi Ward
- Department of Radiation Oncology, Emory University, Atlanta, Georgia, USA
| | - Wendy Zheng
- Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia, USA
| | - Matthew Mistro
- Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia, USA
| | - Bruce Libby
- H. Lee Moffitt Cancer Center, Department of Radiation Oncology, Tampa, Florida, USA
| | - Christopher McLaughlin
- Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia, USA
| | - Timothy N Showalter
- Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia, USA
| | - Einsley M Janowski
- Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia, USA
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Letter to the editor regarding "Reducing dose to rectum by placement of a rectum-emptying tube in cervical cancer patients treated with brachytherapy". Brachytherapy 2022; 21:979-980. [PMID: 36184291 DOI: 10.1016/j.brachy.2022.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 08/02/2022] [Indexed: 12/14/2022]
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Joya M, Nedaie HA, Geraily G, Seiri M, Ghorbani M, Sheikhzadeh P. Intensity-modulated brachytherapy for vaginal cancer. Radiol Phys Technol 2022; 15:387-397. [PMID: 36069978 DOI: 10.1007/s12194-022-00680-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 08/27/2022] [Accepted: 08/30/2022] [Indexed: 10/14/2022]
Abstract
This study aimed to evaluate the dose modulation potential of static and dynamic steel-shielded applicators using the Geant4 Application for Emission Tomography (GATE) Monte Carlo code for the treatment of vaginal cancer. The GATE TOOLKIT (version 9.0) was used to simulate vaginal cancer intensity-modulated brachytherapy (IMBT) in a pelvic water-equivalent phantom. IMBT performance of a multichannel static and single-channel dynamic steel-shielded applicator was compared to that of a conventional multichannel Plexiglas applicator. DoseActors were defined to calculate the absorbed dose and attached to the voxelized target and organs at risk (OARs). 60Co and 192Ir high-dose-rate seeds were used as irradiation sources. Dynamic IMBT decreased the D2cc of the rectum and bladder by 28.67 and 28.11% using the 60Co source and by 40.00 and 36.34% using the 192Ir source, respectively. Static IMBT decreased the D2cc for the rectum and bladder by 11.69 and 9.29% using the 60Co source and by 22.21 and 17.71% using the 192Ir source, respectively. In contrast, absorbed dose parameters (D5, D90, and D100) for the target in the three techniques showed a mean relative variation of 0.96% (0.00-7.49%) for both sources. Static and dynamic IMBT using steel-shielded applicators provided relatively better OAR protection while maintaining similar target coverage in the treatment of vaginal cancer.
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Affiliation(s)
- Musa Joya
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran. .,Radiology Department, Kabul University of Medical Sciences, Kabul, Afghanistan.
| | - Hassan Ali Nedaie
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Ghazale Geraily
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahnaz Seiri
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Molecular and Cellular Imaging (RCMCI), Advanced Medical Technologies and Equipment Institute, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahdi Ghorbani
- Biomedical Engineering and Medical Physics Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Peyman Sheikhzadeh
- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Department of Nuclear Medicine, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
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Reproducibility of vaginal immobilization balloons in situ overnight for cervical cancer brachytherapy. J Contemp Brachytherapy 2021; 13:280-285. [PMID: 34122567 PMCID: PMC8170519 DOI: 10.5114/jcb.2021.106117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 02/23/2021] [Indexed: 11/17/2022] Open
Abstract
Purpose The use of vaginal immobilization balloons placed into the vagina for immobilization of tandem and ovoid (T+O) applicator during high-dose-rate (HDR) brachytherapy delivery has been used at our institution, and seems to have improved our patient comfort, decreased procedure time, and minimized applicator misplacement. We aimed to show that these balloons, while originally marketed for single-day use, are safe and maintain applicator positioning/dosimetry when left in situ overnight for treatment delivery on sequential days. Material and methods Forty-two paired computed tomography (CT) scans from thirteen patients who underwent T+O HDR treatments on sequential days with vaginal immobilization balloons in situ overnight were retrospectively compared to calculate mean change of balloon volumes and balloon/T+O distance to bony landmarks. Dosimetric planning was retroactively performed on day 2 using CT scan of each pair, and the change in estimated radiation delivery to the bladder and rectum was compared. Results No statistically significant overnight changes were found in balloon volumes or anterior balloon positioning. The posterior balloon shifted -0.29 ±0.46 cm (p = 0.03) to the anterior public symphysis and 0.32 ±0.50 cm (p = 0.01) to the right femoral head. The tandem shifted 0.37 ±0.39 cm (p = 0.002) to the pubic symphysis. There was no significant difference found in radiation delivered to the bladder or rectum between the paired scans. Conclusions This study showed minimal change in balloon volumes, balloons/T+O positioning, or in radiation dose to bladder and rectum when the applicator remained overnight. These findings support that inflatable vaginal immobilization balloons remaining in situ overnight for additional HDR T+O treatments on sequential days, is safe and provides stable dosimetry.
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Ferré M, Varela Cagetti L, Zemmour C, Tyran M, Fau P, Chargari C, Tallet A, Gonzague L, Annede P. Reducing dose to rectum by placement of a rectum-emptying tube in cervical cancer patients treated with brachytherapy. Brachytherapy 2021; 20:748-754. [PMID: 33883092 DOI: 10.1016/j.brachy.2021.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 03/03/2021] [Accepted: 03/08/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE Only scarce data are available on the possibility to reduce rectal dose by controlling rectum filling before HDR (high dose rate) IGABT (image-guided adaptive brachytherapy) in LACC (locally advanced cervical carcinoma) patients. We compared dosimetric outcomes before and after the evacuation of gasses using a rectum emptying tube. METHODS AND MATERIAL Sixty CT (computed tomography) scans from 30 consecutive patients with cancer of the cervix undergoing HDR IGABT after EBRT were reviewed. Patients who underwent at least one gas evacuation were included in the analysis. The three-dimensional dosimetric data of the dosimetric plan performed before and after gas evacuation were compared. Primary endpoint was the difference between D2cc of the rectum before and after the procedure. Expected probability of grade 2-4 overall rectum morbidity was assessed using a probit model from the prospective multicenter EMBRACE study. RESULTS Thirty five (58.3%) CT scans from 23 patients (76.7%) requiring gas evacuation were analysed. The mean rectum volume, before and after gas evacuation, was 123.1 cc (sd, ± 60.4) and 66.4 cc (sd, ± 34.8), respectively. For each patient, the volume of the rectum after gas evacuation was lower than before. No major complication occurred during and after the procedure. After gas evacuation, a significant reduction in rectal dose per fraction was observed, on average -4.3 Gy (-38.4%, p < 0.001) for D0.1cc and -1.9 Gy (-30.6%, p < 0.001) for D2cc. Estimated mean probability to develop a grade 2-4 rectum morbidity was significantly lower after gas evacuation, 6.9% (sd,± 1.94) versus 9.5% (sd,± 3.17), p < 0.001. CONCLUSION Gas evacuation using a rectal emptying tube in selected LACC patients treated with HDR BT after chemoradiotherapy, allowed a substantial reduction in the dose to the rectum. Such procedure could be of particular interest when a dose escalation strategy is being considered.
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Affiliation(s)
- Marjorie Ferré
- Department of Radiotherapy, Paoli Calmettes Institute, Marseille, France
| | | | - Christophe Zemmour
- Department of Clinical Research and Innovation, Biostatistics and Methodology Unit, Paoli Calmettes Institute, Marseille, France
| | - Marguerite Tyran
- Department of Radiotherapy, Paoli Calmettes Institute, Marseille, France
| | - Pierre Fau
- Department of Radiotherapy, Paoli Calmettes Institute, Marseille, France
| | - Cyrus Chargari
- Department of Radiation Oncology, Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - Agnès Tallet
- Department of Radiotherapy, Paoli Calmettes Institute, Marseille, France
| | - Laurence Gonzague
- Department of Radiotherapy, Paoli Calmettes Institute, Marseille, France
| | - Pierre Annede
- Department of Radiotherapy, Paoli Calmettes Institute, Marseille, France.
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Wang X, Zhang B, He Q, Kong Y, Dai Z, Meng H, Huang F, Zhang S, Zhu Y, Tan X, Zhen X. Rectum Protection by Rectal Gel Injection in Cervical Cancer Brachytherapy: A Dosimetric Study via Deformable Surface Dose Accumulation and Machine-Learning-Based Discriminative Modeling. Front Oncol 2021; 11:657208. [PMID: 33937068 PMCID: PMC8085420 DOI: 10.3389/fonc.2021.657208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/29/2021] [Indexed: 11/13/2022] Open
Abstract
PURPOSE This retrospective study aimed to evaluate the dosimetric effects of a rectal insertion of Kushen Ningjiao on rectal protection using deformable dose accumulation and machine learning-based discriminative modelling. MATERIALS AND METHODS Sixty-two patients with cervical cancer enrolled in a clinical trial, who received a Kushen Ningjiao injection of 20 g into their rectum for rectal protection via high-dose rate brachytherapy (HDR-BT, 6 Gy/f), were studied. The cumulative equivalent 2-Gy fractional rectal surface dose was deformably summed using an in-house-developed topography-preserved point-matching deformable image registration method. The cumulative three-dimensional (3D) dose was flattened and mapped to a two-dimensional (2D) plane to obtain the rectal surface dose map (RSDM). For analysis, the rectal dose (RD) was further subdivided as follows: whole, anterior, and posterior 3D-RD and 2D-RSDM. The dose-volume parameters (DVPs) were extracted from the 3D-RD, while the dose geometric parameters (DGPs) and textures were extracted from the 2D-RSDM. These features were fed into 192 classification models (built with 8 classifiers and 24 feature selection methods) for discriminating the dose distributions between pre-Kushen Ningjiao and pro-Kushen Ningjiao. RESULTS The rectal insertion of Kushen Ningjiao dialated the rectum in the ambilateral direction, with the rectal column increased from pre-KN 15 cm3 to post-KN 18 cm3 (P < 0.001). The characteristics of DGPs accounted for the largest portions of the top-ranked features. The top-ranked dosimetric features extracted from the posterior rectum were more reliable indicators of the dosimetric effects/changes introduced by the rectal insertion of Kushen Ningjiao. A significant dosimetric impact was found on the dose-volume parameters D1.0cc-D2.5cc extracted on the posterior rectal wall. CONCLUSIONS The rectal insertion of Kushen Ningjiao incurs significant dosimetric changes on the posterior rectal wall. Whether this effect is eventually translated into clinical gains requires further long-term follow-up and more clinical data for confirmation.
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Affiliation(s)
- Xuetao Wang
- Radiation Oncology Department, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Bailin Zhang
- Radiation Oncology Department, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Qiang He
- Radiation Oncology Department, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yilin Kong
- Radiation Oncology Department, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhenhui Dai
- Radiation Oncology Department, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Haoyu Meng
- Radiation Oncology Department, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Fangjun Huang
- School of Biomedical Engineering, Southern Medical University, Guangzhou, China
| | - Shengfeng Zhang
- Radiation Oncology Department, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yuanhu Zhu
- Radiation Oncology Department, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xiang Tan
- Radiation Oncology Department, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xin Zhen
- School of Biomedical Engineering, Southern Medical University, Guangzhou, China
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Dosimetric comparison of two different applicators and rectal retraction methods used in inverse optimization-based intracavitary brachytherapy for cervical cancer. J Contemp Brachytherapy 2020; 12:35-43. [PMID: 32190068 PMCID: PMC7073337 DOI: 10.5114/jcb.2020.92699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 01/11/2020] [Indexed: 01/17/2023] Open
Abstract
Purpose The purpose of this study was to evaluate the dosimetric differences between two different applicators and rectal-retraction methods used in image-guided brachytherapy (IGBT) for locally advanced cervical cancer (LACC). Material and methods Ten patients with LACC treated with definitive chemoradiotherapy and inverse optimization-based IGBT were included in this study. In each patient, at least one fraction of IGBT was performed using tandem-ovoids (TO) with vaginal gauze packing (VGP) or tandem-ring (TR) with rectal-retractor (RR). High-risk clinical target volume (CTVHR) and intermediate-risk CTV (CTVIR) were defined as CTVs, and bladder, rectum, sigmoid, small bowel, urethra, and vaginal mucosa were defined as organs at risk (OARs). All patients received 50.4 Gy external beam radiotherapy (EBRT) in 28 fractions. After EBRT, 28 Gy high-dose-rate (HDR) IGBT in 4 fractions was delivered to central disease. A plan comparison was performed using dose-volume histogram (DVH) and treatment planning parameters for CTVs and OARs. Results There were no significant differences in D90 values of CTVHR. In terms of rectum dose, TR with RR was found to be significantly better than TO with VGP (p < 0.0001 for D2cm3 and p < 0.013 for V5Gy). Although, there were no statistically significant differences in D2cm3 value of bladder, sigmoid, small bowel, upper vaginal mucosa, and urethra, mean value of D2cm3 for all defined OARs were found lower in TR than in TO. Bladder V7Gy, upper vaginal mucosa V7Gy, middle and lower vaginal mucosa D2cm3 values were all found to be significantly lower for TR than for TO (p < 0.035). CTVHR and CTVIR volumes contoured in TR were approximately 11% and 9% smaller than TO, respectively. Conclusions The results showed that there were no statistically differences in D90 value of CTVHR and CTVIR. However, all DVH parameters for OARs in TR with RR were found to be better than in TO with VGP.
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Initial experience using superflab as intravaginal packing during interstitial brachytherapy for advanced gynecologic cancer. J Contemp Brachytherapy 2018; 10:218-224. [PMID: 30038641 PMCID: PMC6052389 DOI: 10.5114/jcb.2018.76522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 05/04/2018] [Indexed: 11/25/2022] Open
Abstract
Purpose Interstitial brachytherapy implemented for locally advanced gynecologic cancer can result in toxicity due to the proximity of organs at risk (OAR). We report our experience using superflab bolus as vaginal packing to displace OAR during interstitial brachytherapy. Material and methods Twelve patients with stage IB-IVA gynecologic cancer were treated with definitive chemoradiation including interstitial brachytherapy. A Syed template was used for a computed tomography (CT)-based pre-plan with magnetic resonance imaging (MRI) fusion. A 1-2 cm superflab bolus was cut and sterilized. The tandem and obturator were placed, and superflab was then inserted into the vagina. Interstitial needles were then placed through the template and superflab as per the pre-plan under transabdominal ultrasound guidance. Prescription doses ranged from 85-90 Gy EQD2 including external beam radiation therapy (EBRT). 5-6 Gy per fraction was delivered biologically effective dose (BID) over 2-3 days in 1-2 implants. Toxicities were evaluated post-treatment, 1 month, and 3 months. Results The rectum, bladder, and sigmoid had significant average displacement from the prescription isodose line. The average reduction in D2cc between pre- and post-implant was 5.19 Gy per fraction (p < 0.0001), 7.19 Gy (p < 0.0004), and 1.78 Gy (p < 0.003) for the rectum, bladder, and sigmoid, respectively. The high-risk target volume (HR-TV) received a median D90 of 104% (range, 58-122%) of the prescription dose, and 92% (range, 71-131%) in the pre-/post-implant plans, respectively (p = 0.4). Conclusions Our initial experience with superflab as vaginal packing demonstrates technical feasibility and dosimetric improvement for OAR.
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Clinical analysis of speculum-based vaginal packing for high-dose-rate intracavitary tandem and ovoid brachytherapy in cervical cancer. J Contemp Brachytherapy 2018; 10:32-39. [PMID: 29619054 PMCID: PMC5881598 DOI: 10.5114/jcb.2018.74316] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 02/15/2018] [Indexed: 11/24/2022] Open
Abstract
Purpose Intra-vaginal packing is used to fix the applicator and displace organs at risk (OAR) during high-dose-rate intracavitary tandem and ovoid brachytherapy (HDR-ICB). We retain the speculum from applicator placement as a dual-function bladder and rectum retractor during treatment. Our objective is to review salient techniques for OAR displacement, share our packing technique, and determine the reduction in dose to OAR and inter-fraction variability of dose to OAR, associated with speculum-based vaginal packing (SBVP) in comparison to conventional gauze packing during HDR-ICB. Material and methods We reviewed HDR-ICB treatment plans for 45 patients, including 10 who underwent both conventional gauze packing and SBVP. Due to institutional inter-provider practice differences, patients non-selectively received either packing procedure. Packing was performed under conscious sedation, followed by cone beam computed tomography used for dosimetric planning. Maximum absolute and percent-of-prescription dose to the International Commission of Radiation Units bladder and rectal points in addition to D0.1cc, D1.0cc, and D2.0cc volumes of the bladder and rectum were analyzed and compared for each packing method using an independent sample t-test. Results Of the 179 fractions included, 73% and 27% used SBVP and gauze packing, respectively. For patients prescribed 6 Gy to point A, SBVP was associated with reduced mean D0.1cc bladder dose, inter-fraction variability in D0.1cc bladder dose by 9.3% (p = 0.026) and 9.0%, respectively, and statistically equivalent rectal D0.1cc, D1.0cc, and D2.0cc. Patients prescribed 5.5 Gy or 5 Gy to point A after dose optimization, were less likely to benefit from SBVP. In the intra-patient comparison, 80% of patients had reduction in at least one rectum or bladder parameter. Conclusions In patients with conducive anatomy, SBVP is a cost-efficient packing method that is associated with improved bladder sparing and comparable rectal sparing relative to gauze packing during HDR-ICB without general anesthesia.
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Safigholi H, Han DY, Mashouf S, Soliman A, Meigooni AS, Owrangi A, Song WY. Direction modulated brachytherapy (DMBT) for treatment of cervical cancer: A planning study with 192 Ir, 60 Co, and 169 Yb HDR sources. Med Phys 2017; 44:6538-6547. [PMID: 28940520 DOI: 10.1002/mp.12598] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 07/27/2017] [Accepted: 09/18/2017] [Indexed: 01/06/2023] Open
Abstract
PURPOSE To evaluate plan quality of a novel MRI-compatible direction modulated brachytherapy (DMBT) tandem applicator using 192 Ir, 60 Co, and 169 Yb HDR brachytherapy sources, for various cervical cancer high-risk clinical target volumes (CTVHR ). MATERIALS AND METHODS The novel DMBT tandem applicator has six peripheral grooves of 1.3-mm diameter along a 5.4-mm thick nonmagnetic tungsten alloy rod. Monte Carlo (MC) simulations were used to benchmark the dosimetric parameters of the 192 Ir, 60 Co, and 169 Yb HDR sources in a water phantom against the literature data. 45 clinical cases that were treated using conventional tandem-and-ring applicators with 192 Ir source (192 Ir-T&R) were selected consecutively from intErnational MRI-guided BRAchytherapy in CErvical cancer (EMBRACE) trial. Then, for each clinical case, 3D dose distribution of each source inside the DMBT and conventional applicators were calculated and imported onto an in-house developed inverse planning optimization code to generate optimal plans. All plans generated by the DMBT tandem-and-ring (DMBT T&R) from all three sources were compared to the respective 192 Ir-T&R plans. For consistency, all plans were normalized to the same CTVHR D90 achieved in clinical plans. The D2 cm3 for organs at risk (OAR) such as bladder, rectum, and sigmoid, and D90, D98, D10, V100, and V200 for CTVHR were calculated. RESULTS In general, plan quality significantly improved when a conventional tandem (Con.T) is replaced with the DMBT tandem. The target coverage metrics were similar across 192 Ir-T&R and DMBT T&R plans with all three sources (P > 0.093). 60 Co-DMBT T&R generated greater hot spots and less dose homogeneity in the target volumes compared with the 192 Ir- and 169 Yb-DMBT T&R plans. Mean OAR doses in the DMBT T&R plans were significantly smaller (P < 0.0084) than the 192 Ir-T&R plans. Mean bladder D2 cm3 was reduced by 4.07%, 4.15%, and 5.13%, for the 192 Ir-, 60 Co-, and 169 Yb-DMBT T&R plans respectively. Mean rectum (sigmoid) D2 cm3 was reduced by 3.17% (3.63%), 2.57% (3.96%), and 4.65% (4.34%) for the 192 Ir-, 60 Co-, and 169 Yb-DMBT T&R plans respectively. The DMBT T&R plans with the 169 Yb source generally resulted in the greatest OAR sparing when the CTVHR were larger and irregular in shape, while for smaller and regularly shaped CTVHR (<30 cm3 ), OAR sparing between the sources were comparable. CONCLUSIONS The DMBT tandem provides a promising alternative to the Con.T design with significant improvement in the plan quality for various target volumes. The DMBT T&R plans generated with the three sources of varying energies generated superior plans compared to the conventional T&R applicators. Plans generated with the 169 Yb-DMBT T&R produced best results for larger and irregularly shaped CTVHR in terms of OAR sparing. Thus, this study suggests that the combination of the DMBT tandem applicator with varying energy sources can work synergistically to generate improved plans for cervical cancer brachytherapy.
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Affiliation(s)
- Habib Safigholi
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Dae Yup Han
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, USA
| | - Shahram Mashouf
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Abraam Soliman
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Ali S Meigooni
- Department of Radiation Therapy, Comprehensive Cancer centers of Nevada, Las Vegas, NV, USA
| | - Amir Owrangi
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - William Y Song
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.,Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, USA
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12
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Kong I, Vorunganti S, Patel M, Farrell T, Timotin E, Quinlan-Davidson S, Pond G, Sur R, Hunter R. Prospective comparison of rectal dose reduction during intracavitary brachytherapy for cervical cancer using three rectal retraction techniques. Brachytherapy 2016; 15:450-455. [PMID: 27090224 DOI: 10.1016/j.brachy.2016.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/11/2016] [Accepted: 03/14/2016] [Indexed: 11/28/2022]
Abstract
PURPOSE To compare three rectal retraction methods on dose to organs at risk, focusing on rectal dose, in cervix cancer patients treated with high-dose-rate intracavitary brachytherapy. METHODS AND MATERIALS A prospective study was conducted on patients with cervical carcinoma treated with chemoradiotherapy, including external beam radiation and four fractions of high-dose-rate intracavitary brachytherapy prescribed to Point A using a ring and tandem applicator under conscious sedation. Rectal retraction methods included: a rectal retractor blade (RR), vaginal gauze packing (VP), and a tandem Foley balloon (FB). All three methods were used in all patients. The RR was used first, and the following applications were randomly assigned to VP or FB. CT planning was used to calculate D2cc for rectum, sigmoid, small bowel, and bladder. The Wilcoxon signed rank test was used to determine if the median dose differences between methods were statistically significant. RESULTS In these 11 patients, median dose (min, max) in cGy to the rectum using RR, FB, and VP was 131 (102, 165), 199 (124, 243), and 218 (149, 299), respectively. The RR demonstrated lower median intrapatient doses to rectum compared with FB and VP (-55 cGy; p = 0.014 and -76 cGy; p = 0.004, respectively). The RR also resulted in lower sigmoid doses. No differences in dose were observed between the VP and FB methods. CONCLUSION The rectal retractor significantly reduced the dose to rectum and sigmoid compared with FP and VP. In patients treated under conscious sedation, the RR method provides the best rectal sparing. There were no significant differences in dose observed between the FB and VP techniques.
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Affiliation(s)
- Iwa Kong
- Department of Oncology, Juravinski Cancer Centre, McMaster University, Hamilton, Canada.
| | - Sachi Vorunganti
- Department of Oncology, Juravinski Cancer Centre, McMaster University, Hamilton, Canada
| | - Malti Patel
- Department of Oncology, Juravinski Cancer Centre, McMaster University, Hamilton, Canada
| | - Thomas Farrell
- Department of Medical Physics, Juravinski Cancer Centre, Hamilton, Canada
| | - Emilia Timotin
- Department of Oncology, Juravinski Cancer Centre, McMaster University, Hamilton, Canada
| | - Sean Quinlan-Davidson
- Department of Oncology, Juravinski Cancer Centre, McMaster University, Hamilton, Canada
| | - Greg Pond
- Department of Oncology, Juravinski Cancer Centre, McMaster University, Hamilton, Canada; Escarpment Cancer Research Institute, McMaster University, Hamilton, Canada
| | - Ranjan Sur
- Department of Oncology, Juravinski Cancer Centre, McMaster University, Hamilton, Canada
| | - Robert Hunter
- Department of Medical Physics, Juravinski Cancer Centre, Hamilton, Canada
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13
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Fan Q, Yeung AR, Amdur R, Helmig R, Park J, Li J, Kahler D, Liu C, Lu B. Image-Guided High-Dose Rate Brachytherapy in Cervix Carcinoma Using Balloon Catheter and Belt Immobilization System. Technol Cancer Res Treat 2016; 16:257-266. [PMID: 26868850 DOI: 10.1177/1533034616631122] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
PURPOSE The efficacy of image-guided high-dose rate brachytherapy for cervical cancer is limited by the ineffective rectal sparing devices available commercially and the potential applicator movement. We developed a novel device using a balloon catheter and a belt immobilization system, serving for rectal dose reduction and applicator immobilization purposes, respectively. METHODS The balloon catheter is constructed by gluing a short inflatable tube to a long regular open-end catheter. Contrast agent (10) cm3 is injected into the inflatable end, which is affixed to the tandem and ring applicator, to displace the posterior vaginal wall. The belt immobilization system consists of a specially designed bracket that can hold and fix itself to the applicator, a diaper-like Velcro fastener package used for connecting the patient's pelvis to the bracket, and a buckle that holds the fasteners to stabilize the whole system. The treatment data for 21 patients with cervical cancer using both balloon catheter and belt immobilization system were retrospectively analyzed. Computed tomography and magnetic resonance images, acquired about 30 minutes apart, were registered to evaluate the effectiveness of the immobilization system. RESULTS In comparison with a virtual rectal blade, the balloon decreased the rectal point dose by 34% ± 4.2% (from 276 ± 57 to 182 ± 38 cGy), corresponding to an extra sparing distance of 7.9 ± 1.1 mm. The maximum sparing distance variation per patient is 1.4 ± 0.6 mm, indicating the high interfractional reproducibility for rectum sparing. With the immobilization system, the mean translational and rotational displacements of the applicator set are <3 mm and <1.5°, respectively, in all directions. CONCLUSIONS The rectal balloon provides significant dose reduction to the rectum and it may potentially minimize patient discomfort. The immobilization system permits almost no movement of the applicator during treatment. This work has the potential to be promoted as a standardized solution for high-dose rate treatment of cervical cancer.
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Affiliation(s)
- Qiyong Fan
- 1 Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, NE, USA.,2 Department of Radiation Oncology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Anamaria R Yeung
- 2 Department of Radiation Oncology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Robert Amdur
- 2 Department of Radiation Oncology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Richard Helmig
- 2 Department of Radiation Oncology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Justin Park
- 2 Department of Radiation Oncology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Jonathan Li
- 2 Department of Radiation Oncology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Darren Kahler
- 2 Department of Radiation Oncology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Chihray Liu
- 2 Department of Radiation Oncology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Bo Lu
- 2 Department of Radiation Oncology, College of Medicine, University of Florida, Gainesville, FL, USA
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14
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Rai B, Patel FD, Chakraborty S, Kapoor R, Sharma SC, Kumaravelu S, Raghukumar P, Aprem AS. Bladder-Rectum Spacer Balloon versus Vaginal Gauze Packing in High Dose Rate Brachytherapy in Cervical Cancer: A Randomised Study. Part II. Clin Oncol (R Coll Radiol) 2015; 27:713-9. [PMID: 26144319 DOI: 10.1016/j.clon.2015.06.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 05/28/2015] [Accepted: 06/12/2015] [Indexed: 10/23/2022]
Abstract
AIMS To compare the inter-fraction dose variation for bladder and rectum using a bladder-rectum spacer balloon (BRSB) versus vaginal gauze packing (VGP) in patients treated with high dose rate intracavitary brachytherapy for carcinoma cervix. MATERIALS AND METHODS After the completion of external radiotherapy, 80 patients were randomised to receive intracavitary brachytherapy using either the BRSB or VGP. The procedure was carried out under general anaesthesia using tandem ovoid applicators. Computed tomography-based planning was carried out and the dose was prescribed to point A. Doses to 0.1, 1 and 2 cm(3) volumes were reported for bladder and rectum for each fraction. The absolute inter-fraction dose variation for each subvolume was compared using the independent sample t-test. RESULT The mean bladder and rectal volumes, as well as the inter-fraction volume variation, were comparable for the BRSB and VGP. The BRSB resulted in a significant reduction in absolute dose as well as the inter-fraction variation for dose to 2 cm(3) rectum volumes (BRSB 0.80 Gy, standard deviation 0.71 Gy versus VGP 1.16 Gy, standard deviation 0.83 Gy; P = 0.04). Cumulative bladder D2cm(3) doses of more than 90 Gy3 were observed in six patients in the BRSB arm versus four patients in the VGP arm (P = 0.73). In both the arms, the rectal D2cm(3) doses did not exceed 75 Gy3. CONCLUSIONS Use of a BRSB resulted in a significant reduction in inter-fraction variation in D2cm(3) rectal dose. However, no significant difference in the inter-fraction dose variation for the other subvolumes of bladder and rectum could be shown between the BRSB and VGP. The use of a BRSB may enable rectal dose reduction and inter-fraction variation where anaesthesia is not routinely used or where there is limited physician expertise. The modification suggested in the BRSB may facilitate its additional usage.
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Affiliation(s)
- B Rai
- Department of Radiotherapy, Regional Cancer Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
| | - F D Patel
- Department of Radiotherapy, Regional Cancer Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - S Chakraborty
- Department of Radiotherapy, Tata Memorial Hospital, Mumbai, India
| | - R Kapoor
- Department of Radiotherapy, Regional Cancer Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - S C Sharma
- Department of Radiotherapy, Regional Cancer Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - S Kumaravelu
- Department of Radiotherapy, Regional Cancer Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - P Raghukumar
- Regional Cancer Centre, Thiruvananthapuram, Kerala, India
| | - A S Aprem
- HLL Life Care Limited, Thiruvananthapuram, Kerala, India
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15
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Wang JL, Yang YZ, Dong WW, Sun J, Tao HT, Li RX, Hu Y. Application of human papillomavirus in screening for cervical cancer and precancerous lesions. Asian Pac J Cancer Prev 2015; 14:2979-82. [PMID: 23803065 DOI: 10.7314/apjcp.2013.14.5.2979] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Cervical cancer is a commonly-encountered malignant tumor in women. Cervical screening is particularly important due to early symptoms being deficient in specificity. The main purpose of the study is to assess the application value of cervical thinprep cytologic test (TCT) and human papillomavirus (HPV) detection in screening for cervical cancer and precancerous lesions. In the study, cervical TCT and HPV detection were simultaneously performed on 12,500 patients selected in a gynecological clinic. Three hundred patients with positive results demonstrated by cervical TCT and/or HPV detection underwent cervical tissue biopsy under colposcopy, and pathological results were considered as the gold standard. The results revealed that 200 out of 12,500 patients were abnormal by TCT, in which 30 cases pertained to equivocal atypical squamous cells (ASCUS), 80 cases to low squamous intraepithelial lesion (LSIL), 70 cases to high squamous intraepithelial lesion (HSIL) and 20 cases to squamous cell carcinoma (SCC). With increasing pathological grade of cervical biopsy, however, TCT positive rates did not rise. Two hundred and eighty out of 12,500 patients were detected as positive for HPV infection, in which 50 cases were chronic cervicitis and squamous metaplasia, 70 cases cervical intraepithelial neoplasia (CIN) I, 60 cases CIN II, 70 cases CIN III and 30 cases invasive cervical carcinoma. Two hundred and thirty patients with high-risk HPV infection were detected. With increase in pathological grade, the positive rate of high-risk HPV also rose. The detection rates of HPV detection to CIN III and invasive cervical carcinoma as well as the total detection rate of lesions were significantly higher than that of TCT. Hence, HPV detection is a better method for screening of cervical cancer at present.
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Affiliation(s)
- Jin-Liang Wang
- Department of General Oncology, Chinese PLA General Hospital, Beijing, China
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16
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Kertzscher G, Rosenfeld A, Beddar S, Tanderup K, Cygler JE. In vivo dosimetry: trends and prospects for brachytherapy. Br J Radiol 2014; 87:20140206. [PMID: 25007037 DOI: 10.1259/bjr.20140206] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The error types during brachytherapy (BT) treatments and their occurrence rates are not well known. The limited knowledge is partly attributed to the lack of independent verification systems of the treatment progression in the clinical workflow routine. Within the field of in vivo dosimetry (IVD), it is established that real-time IVD can provide efficient error detection and treatment verification. However, it is also recognized that widespread implementations are hampered by the lack of available high-accuracy IVD systems that are straightforward for the clinical staff to use. This article highlights the capabilities of the state-of-the-art IVD technology in the context of error detection and quality assurance (QA) and discusses related prospects of the latest developments within the field. The article emphasizes the main challenges responsible for the limited practice of IVD and provides descriptions on how they can be overcome. Finally, the article suggests a framework for collaborations between BT clinics that implemented IVD on a routine basis and postulates that such collaborations could improve BT QA measures and the knowledge about BT error types and their occurrence rates.
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Affiliation(s)
- G Kertzscher
- 1 Centre for Nuclear Technologies, Technical University of Denmark, Roskilde, Denmark
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17
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Han DY, Webster MJ, Scanderbeg DJ, Yashar C, Choi D, Song B, Devic S, Ravi A, Song WY. Direction-modulated brachytherapy for high-dose-rate treatment of cervical cancer. I: theoretical design. Int J Radiat Oncol Biol Phys 2014; 89:666-73. [PMID: 24751413 DOI: 10.1016/j.ijrobp.2014.02.039] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 02/11/2014] [Accepted: 02/26/2014] [Indexed: 11/28/2022]
Abstract
PURPOSE To demonstrate that utilization of the direction-modulated brachytherapy (DMBT) concept can significantly improve treatment plan quality in the setting of high-dose-rate (HDR) brachytherapy for cervical cancer. METHODS AND MATERIALS The new, MRI-compatible, tandem design has 6 peripheral holes of 1.3-mm diameter, grooved along a nonmagnetic tungsten-alloy rod (ρ = 18.0 g/cm(3)), enclosed in Delrin tubing (polyoxymethylene, ρ = 1.41 g/cm(3)), with a total thickness of 6.4 mm. The Monte Carlo N-Particle code was used to calculate the anisotropic (192)Ir dose distributions. An in-house-developed inverse planning platform, geared with simulated annealing and constrained-gradient optimization algorithms, was used to replan 15 patient cases (total 75 plans) treated with a conventional tandem and ovoids (T&O) applicator. Prescription dose was 6 Gy. For replanning, we replaced the conventional tandem with that of the new DMBT tandem for optimization but left the ovoids in place and kept the dwell positions as originally planned. All DMBT plans were normalized to match the high-risk clinical target volume V100 coverage of the T&O plans. RESULTS In general there were marked improvements in plan quality for the DMBT plans. On average, D2cc for the bladder, rectum, and sigmoid were reduced by 0.59 ± 0.87 Gy (8.5% ± 28.7%), 0.48 ± 0.55 Gy (21.1% ± 27.2%), and 0.10 ± 0.38 Gy (40.6% ± 214.9%) among the 75 plans, with best single-plan reductions of 3.20 Gy (40.8%), 2.38 Gy (40.07%), and 1.26 Gy (27.5%), respectively. The high-risk clinical target volume D90 was similar, with 6.55 ± 0.96 Gy and 6.59 ± 1.06 Gy for T&O and DMBT, respectively. CONCLUSIONS Application of the DMBT concept to cervical cancer allowed for improved organ at risk sparing while achieving similar target coverage on a sizeable patient population, as intended, by maximally utilizing the anatomic information contained in 3-dimensional imaging. A series of mechanical and clinical validations are to be followed.
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Affiliation(s)
- Dae Yup Han
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California; Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, California
| | - Matthew J Webster
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California; Department of Physics, University of California San Diego, La Jolla, California
| | - Daniel J Scanderbeg
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California
| | - Catheryn Yashar
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California
| | - Dongju Choi
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California
| | - Bongyong Song
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California
| | - Slobodan Devic
- Medical Physics Unit, McGill University, Montréal, Québec, Canada; Department of Radiation Oncology, Jewish General Hospital, Montréal, Québec, Canada
| | - Ananth Ravi
- Department of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - William Y Song
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California; Department of Medical Physics, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
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18
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Gaudet M, Lim P, Yuen C, Zhang S, Spadinger I, Dubash R, Aquino-Parsons C. Comparative analysis of rectal dose parameters in image-guided high-dose-rate brachytherapy for cervical cancer with and without a rectal retractor. Brachytherapy 2014; 13:257-62. [PMID: 24480263 DOI: 10.1016/j.brachy.2014.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 12/18/2013] [Accepted: 01/02/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE The 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 MATERIALS We 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 D2cc and International Commission on Radiation Units & Measurements (ICRU) rectal point doses were compared between groups using Student's t tests. Predictors of higher rectal D2cc were determined by univariate and multivariate regression analyses. RESULTS Four 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 D2cc (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 D2cc on multivariate analysis. CONCLUSIONS Our 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.
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Affiliation(s)
- Marc Gaudet
- Department of Radiation Oncology, BC Cancer Agency Vancouver Centre, Vancouver, BC, Canada; Département de radio-oncologie, CSSS de Gatineau-Hôpital de Gatineau, Gatineau, QC, Canada.
| | - Peter Lim
- Department of Radiation Oncology, BC Cancer Agency Vancouver Centre, Vancouver, BC, Canada
| | - Conrad Yuen
- Department of Radiation Oncology, BC Cancer Agency Vancouver Centre, Vancouver, BC, Canada
| | - Susan Zhang
- Department of Radiation Oncology, BC Cancer Agency Vancouver Centre, Vancouver, BC, Canada
| | - Ingrid Spadinger
- Department of Radiation Oncology, BC Cancer Agency Vancouver Centre, Vancouver, BC, Canada
| | - Rustom Dubash
- Department of Radiation Oncology, BC Cancer Agency Vancouver Centre, Vancouver, BC, Canada
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