Currently, image-based 3-dimentional (3D) planning brachytherapy allows for a better assessment of gross tumor volume (GTV) and the definition and delineation of target volume in cervix cancer. In this study, we inves...Currently, image-based 3-dimentional (3D) planning brachytherapy allows for a better assessment of gross tumor volume (GTV) and the definition and delineation of target volume in cervix cancer. In this study, we investigated the feasibility of our novel computed tomography (CT)-guided free-hand high-dose- rate interstitial brachytherapy (HDRISBT) technique for cervical cancer by evaluating the dosimetry and preliminary clinical outcome of this approach. Dose-volume histogram (DVH) parameters were analyzed according to the Gynecological GEC-ESTRO Working Group recommendations for image-based 3D treatment in cervical cancer. Twenty cervical cancer patients who underwent CT-guided free-hand HDRISBT between March 2009 and June 2010 were studied. With a median of 5 (range, 4-7) implanted needles for each patient, the median dose of brachytherapy alone delivered to 90% of the target volume (D90 ) was 45 (range, 33-54) Gyα/β10 for high-risk clinical target volume (HR-CTV) and 30 (range, 20-36) Gyα/β10 for intermediate-risk clinical target volume (IR-CTV). The percentage of the CTV covered by the prescribed dose (V100 ) of HR-CTV with brachytherapy alone was 81.9%-99.2% (median, 96.7%). With an additional dose of external beam radiotherapy (EBRT), the median D90 was 94 (range, 83-104) Gyα/β10 for HR-CTV and 77 (range, 70 -87) Gyα/β10 for IR-CTV; the median dose delivered to 100% of the target volume (D100 ) was 75 (range, 66-84) Gyα/β10 for HR-CTV and 65 (range, 57-73) Gyα/β10 for IR-CTV. The minimum dose to the most irradiated 2 cc volume (D2cc ) was 73-96 (median, 83) Gyα/β3 for the bladder, 64-98 (median, 73) Gyα/β3 for the rectum, and 52-69 (median, 61) Gyα/β3 for the sigmoid colon. After a median follow-up of 15 months (range, 3 -24 months), two patients experienced local failure, and 1 showed internal iliac nodal metastasis. Despite the relatively small number of needles used, CT-guided HDRISBT for cervical cancer showed favorable DVH parameters and clinical outcome.展开更多
Purpose: Curative radiation therapy is an established treatment option for non-surgical patients with early-stage endometrial carcinoma. Dosimetric analyses were performed using a single tandem, double tandem, Heyman ...Purpose: Curative radiation therapy is an established treatment option for non-surgical patients with early-stage endometrial carcinoma. Dosimetric analyses were performed using a single tandem, double tandem, Heyman capsules, and an inflatable intrauterine balloon to assess the dose homogeneity and conformality in the definitive treatment of inoperable endometrial cancer. Methods and Materials: Patients’ informed-consent was obtained. Dosimetric analyses were performed using four different after-loading applicators to assess the dose homogeneity and conformality of isodose to the three-dimensional (3-D) shape of the target volume (uterus) based on CT data in four patients (n = 4). The single tandem and double tandems were standard Fletcher-type (Nucletron Corporation, Columbia, MD). Heyman capsules were the disposable after-loading type (Radiation Products Design, Inc., Albertville, MN). The inflatable balloon with a central bi-lumen catheter was the Mammo Site Radiation Therapy System (Proxima Therapeutics, Alpharetta, GA) that is currently used for local breast brachytherapy. Treatment planning and dosimetric analyses for all four techniques were done with HDR PLATO Brachytherapy (v14.2.3) Software (Nucletron Corporation). Results: The average dose gradient within the target (uterine wall) is highest with the tandem methods, followed by Heyman capsules. The intrauterine balloon method showed the least dose gradient across the uterine wall. The corresponding average homogeneity indices were 3.81, 3.83, 2.97, 2.50 for single tandem, double tandem, Heyman capsules, and intrauterine balloon respectively. Conclusions: The intra-uterine inflatable balloon appears to have the best overall dosimetric advantages for the treatment of the uterine wall. Furthermore, the potential ease of use, shorter time of applicator placement, and better patient comfort warrant further investigation and subsequent clinical implementation.展开更多
The Monte Carlo(MC)simulation is regarded as the gold standard for dose calculation in brachytherapy,but it consumes a large amount of computing resources.The development of heterogeneous computing makes it possible t...The Monte Carlo(MC)simulation is regarded as the gold standard for dose calculation in brachytherapy,but it consumes a large amount of computing resources.The development of heterogeneous computing makes it possible to substantially accelerate calculations with hardware accelerators.Accordingly,this study develops a fast MC tool,called THUBrachy,which can be accelerated by several types of hardware accelerators.THUBrachy can simulate photons with energy less than 3 MeV and considers all photon interactions in the energy range.It was benchmarked against the American Association of Physicists in Medicine Task Group No.43 Report using a water phantom and validated with Geant4 using a clinical case.A performance test was conducted using the clinical case,showing that a multicore central processing unit,Intel Xeon Phi,and graphics processing unit(GPU)can efficiently accelerate the simulation.GPU-accelerated THUBrachy is the fastest version,which is 200 times faster than the serial version and approximately 500 times faster than Geant4.The proposed tool shows great potential for fast and accurate dose calculations in clinical applications.展开更多
Objective:To evaluate the physical properties of commonly used 3D-printed materials and the dose attenuation around a high-dose-rate ^(192)Ir source,in order to provide a reference for selecting appropriate 3D-printed...Objective:To evaluate the physical properties of commonly used 3D-printed materials and the dose attenuation around a high-dose-rate ^(192)Ir source,in order to provide a reference for selecting appropriate 3D-printed materials for brachytherapy.Methods:Fifteen 3D-printed materials(12 non-metallic material and 3 metallic material)were assessed.Each material was fabricated into a wafer with a diameter of 30 mm and thickness of 3 mm using 3D printing.The CT number of each material was measured,and attenuation measurements were conducted with a Valencia skin applicator and well-type ionization chamber.192Ir was used as the radioactive source,and the attenuated ionization charges were normalized against that obtained in the presence of a solid water phantom at the same depth.Results:The CT number of nylon was(-7.78±3.36)HU,closest to water among all materials.The CT numbers of the other 11 non-metallic materials were below 300 HU.Moreover,the CT number of the Al alloy was(1,350.89±374.55)HU,while the CT numbers of the Ti alloy and stainless steel exceeded 2,976 HU,reaching the upper limit of the CT number range.The results of the attenuation measurements were normalized with the solid water phantom.The average attenuation coefficients of a polyamide,epoxy resin,photosensitive resin,carbon fiber,silica gel,Al alloy,Ti alloy,and stainless steel were 1.003,0.994,0.992,0.995,0.995,0.967,0.939,and 0.866,respectively.Conclusions:Among the common 3D-printed materials with a density similar to that of water,nylon exhibited the best performance,while the metallic materials caused significant dose attenuation and exhibited CT number distortion.As a result,care should be taken when metallic materials are used as 3D-printed materials for brachytherapy.展开更多
文摘Currently, image-based 3-dimentional (3D) planning brachytherapy allows for a better assessment of gross tumor volume (GTV) and the definition and delineation of target volume in cervix cancer. In this study, we investigated the feasibility of our novel computed tomography (CT)-guided free-hand high-dose- rate interstitial brachytherapy (HDRISBT) technique for cervical cancer by evaluating the dosimetry and preliminary clinical outcome of this approach. Dose-volume histogram (DVH) parameters were analyzed according to the Gynecological GEC-ESTRO Working Group recommendations for image-based 3D treatment in cervical cancer. Twenty cervical cancer patients who underwent CT-guided free-hand HDRISBT between March 2009 and June 2010 were studied. With a median of 5 (range, 4-7) implanted needles for each patient, the median dose of brachytherapy alone delivered to 90% of the target volume (D90 ) was 45 (range, 33-54) Gyα/β10 for high-risk clinical target volume (HR-CTV) and 30 (range, 20-36) Gyα/β10 for intermediate-risk clinical target volume (IR-CTV). The percentage of the CTV covered by the prescribed dose (V100 ) of HR-CTV with brachytherapy alone was 81.9%-99.2% (median, 96.7%). With an additional dose of external beam radiotherapy (EBRT), the median D90 was 94 (range, 83-104) Gyα/β10 for HR-CTV and 77 (range, 70 -87) Gyα/β10 for IR-CTV; the median dose delivered to 100% of the target volume (D100 ) was 75 (range, 66-84) Gyα/β10 for HR-CTV and 65 (range, 57-73) Gyα/β10 for IR-CTV. The minimum dose to the most irradiated 2 cc volume (D2cc ) was 73-96 (median, 83) Gyα/β3 for the bladder, 64-98 (median, 73) Gyα/β3 for the rectum, and 52-69 (median, 61) Gyα/β3 for the sigmoid colon. After a median follow-up of 15 months (range, 3 -24 months), two patients experienced local failure, and 1 showed internal iliac nodal metastasis. Despite the relatively small number of needles used, CT-guided HDRISBT for cervical cancer showed favorable DVH parameters and clinical outcome.
文摘Purpose: Curative radiation therapy is an established treatment option for non-surgical patients with early-stage endometrial carcinoma. Dosimetric analyses were performed using a single tandem, double tandem, Heyman capsules, and an inflatable intrauterine balloon to assess the dose homogeneity and conformality in the definitive treatment of inoperable endometrial cancer. Methods and Materials: Patients’ informed-consent was obtained. Dosimetric analyses were performed using four different after-loading applicators to assess the dose homogeneity and conformality of isodose to the three-dimensional (3-D) shape of the target volume (uterus) based on CT data in four patients (n = 4). The single tandem and double tandems were standard Fletcher-type (Nucletron Corporation, Columbia, MD). Heyman capsules were the disposable after-loading type (Radiation Products Design, Inc., Albertville, MN). The inflatable balloon with a central bi-lumen catheter was the Mammo Site Radiation Therapy System (Proxima Therapeutics, Alpharetta, GA) that is currently used for local breast brachytherapy. Treatment planning and dosimetric analyses for all four techniques were done with HDR PLATO Brachytherapy (v14.2.3) Software (Nucletron Corporation). Results: The average dose gradient within the target (uterine wall) is highest with the tandem methods, followed by Heyman capsules. The intrauterine balloon method showed the least dose gradient across the uterine wall. The corresponding average homogeneity indices were 3.81, 3.83, 2.97, 2.50 for single tandem, double tandem, Heyman capsules, and intrauterine balloon respectively. Conclusions: The intra-uterine inflatable balloon appears to have the best overall dosimetric advantages for the treatment of the uterine wall. Furthermore, the potential ease of use, shorter time of applicator placement, and better patient comfort warrant further investigation and subsequent clinical implementation.
基金supported by the National Natural Science Foundation of China(No.11875036)。
文摘The Monte Carlo(MC)simulation is regarded as the gold standard for dose calculation in brachytherapy,but it consumes a large amount of computing resources.The development of heterogeneous computing makes it possible to substantially accelerate calculations with hardware accelerators.Accordingly,this study develops a fast MC tool,called THUBrachy,which can be accelerated by several types of hardware accelerators.THUBrachy can simulate photons with energy less than 3 MeV and considers all photon interactions in the energy range.It was benchmarked against the American Association of Physicists in Medicine Task Group No.43 Report using a water phantom and validated with Geant4 using a clinical case.A performance test was conducted using the clinical case,showing that a multicore central processing unit,Intel Xeon Phi,and graphics processing unit(GPU)can efficiently accelerate the simulation.GPU-accelerated THUBrachy is the fastest version,which is 200 times faster than the serial version and approximately 500 times faster than Geant4.The proposed tool shows great potential for fast and accurate dose calculations in clinical applications.
文摘目的评估3种深度学习(DL)算法在子宫内膜癌(EC)术后患者高剂量率近距离放射治疗(high-dose-rate brachytherapy,HDR BT)中,自动分割临床靶区(CTV)的应用结果。方法数据集由306名子宫内膜癌术后患者的计算机断层扫描(CT)图像组成,按比例分为训练集(246例)、验证集(30例)和测试集(30例)。比较3种深度卷积神经网络模型(3D U-Net、3D Res U-Net和V-Net)在CTV分割上的性能。采用定量指标分别为戴斯相似性系数(DSC)、豪斯多夫距离(HD)、豪斯多夫距离第95百分位数(HD95%)和交并比(IoU)。结果在测试阶段中,3D U-Net、3D Res U-Net和V-Net分割CTV得到的DSC平均值分别为0.90±0.07、0.95±0.06和0.95±0.06;HD平均值(mm)分别为2.51±1.70、0.96±1.01和0.98±0.95;HD95%平均值(mm)分别为1.33±1.02、0.65±0.91和0.40±0.72,IoU平均值分别为0.85±0.11、0.91±0.09和0.92±0.09。其中,V-Net分割结果与高级临床医生勾画结果更接近,CTV的分割时间<3.2 s,节省了临床医生的工作时间。结论V-Net在CTV分割方面表现最佳,定量指标和临床评估均优于其他模型。该方法与基准真实值高度一致,有效减少医生间差异,缩短治疗时间。
基金supported by grants from the National High Level Hospital Clinical Research Funding(2022-PUMCH-A-101)the National High Level Hospital Clinical Research Funding(2022-PUMCH-B-052),China.
文摘Objective:To evaluate the physical properties of commonly used 3D-printed materials and the dose attenuation around a high-dose-rate ^(192)Ir source,in order to provide a reference for selecting appropriate 3D-printed materials for brachytherapy.Methods:Fifteen 3D-printed materials(12 non-metallic material and 3 metallic material)were assessed.Each material was fabricated into a wafer with a diameter of 30 mm and thickness of 3 mm using 3D printing.The CT number of each material was measured,and attenuation measurements were conducted with a Valencia skin applicator and well-type ionization chamber.192Ir was used as the radioactive source,and the attenuated ionization charges were normalized against that obtained in the presence of a solid water phantom at the same depth.Results:The CT number of nylon was(-7.78±3.36)HU,closest to water among all materials.The CT numbers of the other 11 non-metallic materials were below 300 HU.Moreover,the CT number of the Al alloy was(1,350.89±374.55)HU,while the CT numbers of the Ti alloy and stainless steel exceeded 2,976 HU,reaching the upper limit of the CT number range.The results of the attenuation measurements were normalized with the solid water phantom.The average attenuation coefficients of a polyamide,epoxy resin,photosensitive resin,carbon fiber,silica gel,Al alloy,Ti alloy,and stainless steel were 1.003,0.994,0.992,0.995,0.995,0.967,0.939,and 0.866,respectively.Conclusions:Among the common 3D-printed materials with a density similar to that of water,nylon exhibited the best performance,while the metallic materials caused significant dose attenuation and exhibited CT number distortion.As a result,care should be taken when metallic materials are used as 3D-printed materials for brachytherapy.
