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Objective @#To verify the feasibility of using a homemade lung phantom for quality control of Cyberknife by comparing the measurement results of the homemade lung phantom and CIRS dynamic phantom in E2E testing of Cyberknife lung tracking. @*Methods @#The patient treatment process was simulated, including CT positioning, plan design, irra- diation implementation, film scanning, and analysis using the homemade phantom and CIRS phantom. The two phantoms were measured five times using MLC under the S7 generation Cyberknife and five times using Iris under the M6 generation Cyberknife. The differences in measurement results between the two phantoms were analyzed using independent sample t-test.@*Results @#For the S7 generation Cyberknife, the statistical analysis of differences between the two phantoms in the detection values on the X-axis, Y-axis, Z-axis, and total deviation showed P values of 0.236, 0.175, 0.289, and 0.668, respect- ively. For the M6 generation Cyberknife, the statistical analysis showed P values of 0.880, 0.891, 0.573, and 0.433, respect- ively. The P values were all > 0.05. Therefore, there were no statistically significant differences in the detection results between the homemade lung phantom and the CIRS phantom under the S7 and M6 generation Cyberknife. The total deviation values were <1.5 mm.@*Conclusion @#The homemade lung phantom and CIRS phantom have consistent measurement results in the E2E testing of Cyberknife lung tracking and meet the requirements of Report of AAPM TG-135 and WS 667- 2019 standard. Therefore, the homemade lung phantom is feasible for clinical quality control of Cyberknife.
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Objective:To investigate the necessity and feasibility of the virtual simulation teaching experiment software of the bronchoscopy intelligent navigation-based fiducial marker implantation technology in the clinical application of radiotherapy.Methods:This study developed a 3D virtual operation and interactive system using the Unity3D engine, tools including 3Dmax and Maya, and the SQL database. The scenes in the system were produced using the currently popular next-generation production process. Targeting the priorities and difficulties in the implantation of fiducial markers, the system developed in this study allowed for simulated demonstration and training based on 12 steps and 10 knowledge points. Internal tests and remote evaluation tests were adopted in this system to obtain the test result of each subject. Then, the application value of the system was analyzed based on the test result.Results:As of May 1, 2022, the system had received 2 409 views and 425 test participants, with an test completion rate of 100% and an experiment pass rate of 96.5%. Moreover, this system won unanimous praise from 167 users, primarily including the students majoring in multilevel medical imaging technology and medical imaging science from the Fujian Medical University, as well as the radiotherapy-related staff of this university.Conclusions:The virtual simulation teaching experiment software of the bronchoscopy intelligent navigation-based fiducial marker implantation technology can be applied to the teaching of students and the training of related professionals.
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Objective:To investigate the effects of different small monitor unit (MU) beam deletion optimization method in the CyberKnife treatment planning system on the calculated planned dose to brain tumors.Methods:A total of 17 patients with brain metastases treated in our hospital from June, 2021 to February, 2022 were selected for this study. A treatment plan was designed for each patient using the multiPlan system in the CyberKnife VSI system as the group without optimization. To improve the efficiency, the generated original plans should be optimized first by deleting some small MUs, forming an experience group and an optimization group for each patient. For the experience group, beams below 30 MU were deleted according to experience. For the optimization group, beams below the MU value calculated based on the second derivative method were deleted. Finally, the parameters of the two groups were statistically compared. The main evaluation parameters included the node number, the beam number, the total number of MUs, the estimated treatment duration, doses to 2% and 95% planning target volumes (PTV D2 and PTV D95), average dose to PTV ( Dmean), average dose to brain tissue ( Dmean-Brain), conformity index (CI), new conformity index (nCI), gradient index (GI), coverage, and the maximum doses to the brainstem and left and right lens ( Dmax-BS, Dmax-LL, and Dmax-RL), and the average doses to the dose shells 20 mm and 40 mm away from PTV (Shell20 and Shell40). Results:The two optimization method met the requirements for the prescription dose delivery to more than 98% PTV. There were statistical differences in the node number ( H = 7.97, P< 0.05) and estimated treatment duration ( H = 6.60, P < 0.05) among the group without MP optimization, the experience group, and the optimization group, with the estimated treatment duration and node number of the optimization group less than those of the group without MP optimization ( P < 0.05). There were no statistically significant differences in other parameters among the three groups ( P > 0.05). The PTV was moderately positively correlated with the treatment duration ( r=0.79, P < 0.01) and beam number ( r=0.78, P < 0.01) of the experience group, and was also moderately positively correlated with the treatment duration ( r=0.69, P < 0.01) and beam number ( r=0.71, P < 0.01) of the optimization group. Conclusions:For the CyberKnife planning of heads, the small MU beam deletion optimization method based on the second derivative can further shorten the treatment duration while ensuring no significant differences in the distribution of doses to organs at risk and targets. Moreover, this method is more effective in optimizing the plans for a large PTV volume.
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Objective:To evaluate the feasibility of a novel liver fiducial marker implantation method for internal fixation and removal of rabbit livers, in order to use in Cyberknife tracking therapy.Methods:Experiments were conducted in vivo and in vitro. In the in vivo experiment, three fiducial markers were implanted percutaneously in each liver of ten rabbits under anesthesia, and the fourth fiducial marker with an external catheter and fixed thin wire was implanted ten days later. After the reference group (the first and the second maker), and the casing group (the first and the fourth marker) were respectively registered and tracked with the Cyberknife, the implantation success rate, registration accuracy, and removal safety of fiducial markers were assessed. The tensile test was performed using liver in vitro by measuring the resistance required to dislodge the spring coil fiducial markers and the fiducial markers without spring coil from liver. Results:The intrahepatic catheter implantation and removal of fiducial marker in rabbit liver had a success rate of 100% and no distant migration. The operation-related and postoperative complications were not occurred. All fiducial markers were successfully traced. Compared to the reference group, the casing group had slightly higher translational errors in supero-inferior and antero-posterior directions ( Z=-11.77, -4.57, P<0.05), and lower translational errors in left-right direction ( Z=-2.52, P<0.05). The dislodgement forces for spring coil fiducial markers was (2.23±0.85) N, significantly different with (0.81±0.13) N for fiducial markers without spring coil ( Z=- 2.31, P < 0.05). Conclusions:The spiral coil structure provides superior fixation in the punctured needle channel, the thin line limits the distant displacement of the fiducial marker outside the liver, and the catheter establishes a channel for the removal. The general operation is simple and easy.
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Objective:To verify radiation shielding effect of the maze of the CyberKnife room, so as to identify and correct the deficiencies in the shielding designs in certain circumstances.Methods:In line with the radiation protection shielding design scheme of the CyberKnife room provided by the producer, the consideradtions are focused on the useful beam that could mainly pass through the image center, but not the outer wall of the maze. However, during the inspection and acceptance of radiological protection in the built room, it was found that in a certain situations useful wire did not pass through the imaging center. Therefore, the additional shielding and protection facilities were built and verified.Results:After verification and acceptance on the scene, in the case where the useful beam was passing through the image center, the highest ambient dose equivalent rate at the concerned points 30 cm away from the outer wall of the maze was 0.31 μSv/h, less than the control level 10 μSv/h. In the opposite case, the highest ambient dose equivalent rate at the same points as above was 301.67 μSv/h, ablut 30 times as much as the control level. After the thickness in maze outer wall was enhanced, the highest ambient dose equivalent rate at the same as above was 2.14 μSv/h. This testing result met the concerned national standard.Conclusions:It is desirable that in designing the outer wall shielding in the maze in a CyberKnife room, attention should be paid to whether or not the useful beam could pass through the image center, or otherwise directly irradiate on the maze on the basis of the movement range of the accelerator. Shielding wall thickness should be calculated on the basis of the irradiation ragne and the distance between source location and the concerned points to ensure being in compliance with the requirements of the concerned national standard. Meanwhile, it should protect the workers occupying at the concerned locations from receiving higher radiation doses.
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Objective:To explore the feasibility of recoverable fiducial marker implantation guided using the intelligent navigation bronchoscopy technology in the Cyberknife Synchrony-based respiratory tracking.Methods:CT scans of an inflatable pig lung after anti-rot processing were obtained. Then, eight simulated tumor lesion sites were designed in the left and right lung lobes using intelligent navigation software, with four classified as the sputum bronchial environment group and four classified as the wet bronchial environment group. Based on the implantation principle of Cyberknife fiducial markers, 32 recoverable fiducial markers were implanted around various simulated tumor lesions via bronchus under intelligent guidance. Then, the end-expiratory state of the pig lung was simulated, the pig lung was scanned again to obtain CT images of the implanted recoverable fiducial markers, and the number of successfully implanted fiducial markers was recorded. Eight deliverable Synchrony treatment protocols were designed using the Cyberknife planning system (Multiplan v4.6), and then the pig lung with simulated respiratory movements was exposed to radiation. After radiation, the implanted recoverable fiducial markers were retrieved using the bronchoscopy technique, and the number of successfully retrieved fiducial markers was recorded. Moreover, the translational errors, rotational errors, and rigid body errors were extracted from the Cyberknife log file and analyzed.Results:No recoverable fiducial markers slipped or fell during the experiment. Thirty-two recoverable fiducial markers were successfully implanted and recovered under the guidance of intelligent navigation bronchoscopy, with implantation and recovery success rates of both 100%. Moreover, the tracking rate and rigid body errors of the fiducial markers were 100% and less than 5 mm, respectively. The data from the Cyberknife log file indicated that there was no significant difference between the sputum bronchial environment group and the wet bronchial environment group in the translational errors in the left-right direction, the rotational errors in the roll direction, and the rotational errors in the pitch direction ( P>0.05). Compared to the wet bronchial environment group, the sputum bronchial environment group had slightly higher translational errors in front-back ( Z=-3.57, P<0.01) and cranio-caudal ( Z=-2.53, P<0.05) directions, lower rotational errors along the yaw axis ( Z = -3.88, P < 0.01), and lower rigid body error ( Z=-3.32, P<0.01), and the differences were all statistically significant. Conclusions:The recoverable fiducial marker implantation guided using the intelligent navigation bronchoscopy technology is feasible. Recoverable fiducial markers are stable in the bronchus of the phantom, and the Cyberknife tracking precision can meet clinical requirements. Therefore, the recoverable fiducial marker implantation guided using the intelligent navigation bronchoscopy technology has promising prospects in clinical and teaching applications.
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Objective:To provide a new morning check method for the output dose stability of the multileaf collimator (MLC) of the CyberKnife M6 (CK-M6) system.Methods:The CT images of a verification phantom with a size of 20 cm × 20 cm × 10 cm were transmitted into the Precision Treatment Plan ning System (ver. 1.1.1.1). The high-precision alignment between the accelerator output front and the fixed position of the phantom surface was achieved using the fiducial tracking method. A 10 cm × 10 cm radiation field was formed by the MLC and a DailyCheck plan with an output of 200 MU was designed. The repeatability, sensitivity, and accuracy of the DailyCheck plan were measured, and the CK-M6 system was continuously tested for one month using the artificial fixed method and the DailyCheck plan designed in this study. Results:The average and the standard deviation of 10 repeated measurements by the DailyCheck plan were 492.28 pC and 0.09, respectively, indicating good stability. There was a linear correlation between the measured values and the output dose, with a correlation coefficient of R2 > 0.999. Moreover, there was a position deviation of 2 mm between the phantom and the accelerator output front, and the result ant effect on the measured values was equivalent to a dose deviation caused by an output of 1.24 MU. The result from the continuous measurement of both the artificial fixed method and the DailyCheck plan fell within permissible limits, showing high consistency. Conclusions:The DailyCheck plan established through the fiducial tracking of a verification phantom can achieve the convenient, quick, and accurate daily detection of the output dose stability of the MLC of CK-M6. Therefore, this method can be widely applied in the clinical quality control of the CK-M6 system.
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OBJECTIVE@#To assess the potential dosimetric effects of arms movement in patients with Cyberknife spine tumors.@*METHODS@#In the study, 12 patients with thoracic and lumbar tumors were retrospectively selected respectively. The contour of the patient's arms was sketched and the CT density was modified to be equivalent to air in order to simulate the extreme case when the arm was completely removed from the radiation fields. The dose of simulated plan was re-calculated with the original beam parameters and compared with the original plan. The changes of V100, D95, and D90, conformity index (CI) and heterogeneity index (HI) in planning target volume (PTV), as well as Dmax, D1cc and D2cc in the spinal cord, stomach, esophagus, and intestines were analyzed by comparing with the original plans.@*RESULTS@#Compared with the original treatment plan, V100, D95, D90 and CI of PTV for the simulated plan was increased by 0.86%, 2.02%, 1.97% and 0.80% respectively, the difference was statistically significant (P < 0.05). Dmax, D1cc and D2cc of spinal cord was increased by 2.35%, 0.59% and 1.49% on average, compared with the original plan, the difference was statistically significant (P < 0.05). The difference was statistically significant only in average D2cc of stomach, which was increased by 1.70%, compared with the original plan (P < 0.05). There was no significant difference in dose change of eso-phagus and intestine between the original and simulated plans.@*CONCLUSION@#This study analyzed the most extreme arm position in spinal tumor of radiation therapy based on Cyberknife. It was found that the change of arm position had little effect on dosimetry. In addition, with the change of arm position, the dose in PTV and organ at risk (OAR) increased, but the increase was relatively small. Therefore, in some special cases where the patient really can't keep the arm position consistent during treatment, reasonable adjustment can be accepted. However, in order to ensure accurate radiotherapy, patient position should be as stable and consistent as possible.
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Humanos , Brazo , Radiocirugia , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador , Radioterapia de Intensidad Modulada , Estudios Retrospectivos , Neoplasias de la Columna Vertebral/cirugíaRESUMEN
Objective@#To discuss the feasibility of applying home-made auto quality assurance (AQA) phantom in Cyberknife AQA test.@*Methods@#The same treatment plan for AQA test was designed in the Cyberknife treatment planning system. The AQA tests were performed under the same conditions using the home-made AQA phantom and the AQA phantom in the fourth-generation (G4) Cyberknife mode and the fifth-generation (VSI) Cyberknife mode, respectively, and each measurement was repeated five times to analyze and compare the differences in test results between the two phantoms.@*Results@#The total deviations of the home-made AQA phantom and the AQA phantom in the AQA test under the G4 Cy- berknife mode were (0.28 ± 0.12) mm and (0.28 ± 0.15) mm, respectively (P > 0.05); the test results under the VSI Cy- berknife mode were (0.46 ± 0.19) mm and (0.50 ± 0.07) mm, respectively (P > 0.05); the total deviations of all test results were smaller than 1.0 mm, which met the requirements of WS 667—2019 Specification for Testing of Quality Control in Ro- botic Arm Radiotherapy Device.@*Conclusion@#The test results of the home-made AQA phantom and the AQA phantom are consistent in the AQA test, and the home-made AQA phantom can be used for Cyberknife quality control.
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Objective:To analyze the influence of tracking error of Xsight lung tracking system caused by cardiac beating.Methods:48 patients with lung tumors adjacent to the heart were enrolled into this study. The tumor movement curves were collected by the Xsight lung tracking system and recorded in the treatment log files during the Cyberknife treatment process. The curves were subject to filtering analysis and the respiratory motion of < 1 Hz and the cardiac beating motion of > 1 Hz were separated. According to the filtering results, the patient treatment tracking data were divided into two groups based on whether the cardiac beating wave of >1 Hz existed. The tracking errors were statistically compared between two groups based on the X-ray imaging data collected by Xsight lung tracking system during treatment.Results:For the fractionation with cardiac beat information, the tracking errors of the patient′s related models were (1.45 ± 0.99), (0.46 ± 0.21) and (0.70 ± 0.54) mm in the left-right, superior-inferior and anterior-posterior direction, respectively. For the fractionation without cardiac beat information, the tracking errors of the patient′s related models were (1.52 ± 1.17), (0.63 ± 0.37) and (1.07 ± 0.62) mm in the left-right, superior-inferior and anterior-posterior direction, respectively. The tracking errors in the superior-inferior and anterior-posterior direction of patients with accurate cardiac beat models were 28.34% and 34.86% less than those of their counterparts without accurate cardiac beat models and there was significant difference (both P<0.05). Conclusion:The tracking accuracy of Xsight lung tracking system will be significantly improved if the cardiac beat model is accurately established.
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Introducción: La dupla Cyberknife y bisturí de rayos gamma (Infini) que se describe es la primera en Latinoamérica. Ambas máquinas han mostrado ser los mejores equipos para radiocirugía intracraneal. Se describe la experiencia inicial de Cyberknife en Centroamérica y su incorporación a un programa existente de bisturí de rayos gamma por vía de análisis comparativos dosimétricos. Material y método: En el año 2019 se realizaron planes comparativos y se trataron 180 pacientes con radiocirugía intracraneal con ambos sistemas tanto en patología tumoral, como vascular y funcional. Resultados: En el análisis dosimétrico comparativo en el gradiente de dosis de Infini mostró ser superior a Cyberknife en todos los casos. Para una esfera utilizando el colimador de 4 mm en Infini y de 5 mm en Cyberknife utilizando un plan isocéntrico con el -Trigeminal Path- el gradiente de dosis para Infini fue de 1.5 y para Cyberknife de 1.66. Para los casos de patología el gradiente de dosis media para Infini fue de 3 mm y para Cyberknife de 3.8 mm. Dando un puntaje de gradiente de dosis (Gradient Score Index) si Infini fuese de 100, Cyberknife obtuvo 87.3. Cyberknife mostró mejor conformalidad y cobertura (97% versus 96%) para todos los targets. Entre enero 2019 y enero 2020 se realizaron 180 radiocirugías, 60 con Cyberknife y 120 con Infini, 60 pacientes recibieron 146 sesiones con Cyberknife, radiocirugía fraccionada 39 (65%) y 21 (35%) en sesión única. Las dosis medias en tumores en dosis única fue 15 Gy (12.5 a 25 Gy) y en radiocirugía fraccionada 21 Gy (18 y 35). Ningún paciente ha experimentado toxicidad mayor a grado dos. Conclusiones: El bisturí de rayos gamma rotatorio reveló superioridad en gradiente de dosis con relación al Cyberknife. En su primer año Cyberknife ha mostrado ser una herramienta segura en el tratamiento de patología intracraneal. Más seguimiento clínico y radiológico es necesario para verificar su efectividad comparativa
Introduction: The match between Cyberknife and Infini here described in this article is the first in Latinamerica. Both machines have proven to be the best for intracranial radiosurgery, we describe our initial experience with Cyberknife in Central America and how it was incorporated in an existing gamma ray program by ways of dosimetry comparisons. Methods: During 2019 comparative plans were made and a total of 180 patients received intracranial radiosurgery with both technologies, patients were treated for tumors, vascular anomalies, and functional pathology. Results: Basic dosimetry analysis regarding dose gradient the Infini proved superior to Cyberknife in all plans. For a sphere using the 4 mm collimator in Infini and the 5 mm in Cyberknife along with an isocentric plan using the -Trigeminal Path- dose gradient was 1.5 for Infini and 1.66 for Cyberknife. For the pathology cases Infini was 3 mm and for Cyberknife 3.8 mm on mean. Giving a Gradient Score Index (GSI) if Infini would be 100, Cyberknife would be 87.3. Cyberknife showed better conformality and coverage for all pathology targets (97% versus 96%). From January 2019 to January 2020, 180 intracranial radiosurgeries were done, 60 with Cyberknife and 120 with Infini, 60 patients received 146 sessions with Cyberknife, fractionated scheme 39 (65%) and 21 (35%) single dose. The median dose for tumors was 15 Gy (12.5 a 25 Gy) for single session and 21 Gy (18 y 35) for fractionated scheme. No patient experienced a higher toxicity tan grade two. Conclusions: In its first year Cyberknife has shown to be safe in treating intracranial pathology. Infini had a better dose gradient than Cyberknife. Longer clinical and radiological follow-up is needed to verify its comparative effectiveness.
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Humanos , Radiocirugia , Cerebro , Metástasis de la Neoplasia , Neoplasias , NeurocirugiaRESUMEN
Circumscribed choroidal hemangioma is a benign vascular hamartoma without systemic associations. For symptomatic cases, treatment options are photodynamic therapy (PDT), transpupillary thermotherapy (TTT), intravitreal injection of anti-vascular endothelial growth factor (VEGF), or radiation therapy. CyberKnife radiosurgery is an image-guided radiation therapy that delivers radiation to lesions anywhere in the body with an accuracy of 0.5 mm without damage to surrounding structures. We report a case of circumscribed choroidal hemangioma which was successfully treated with CyberKnife therapy. The literature search reveals cases of uveal melanoma, intraocular, and periocular lymphoma successfully treated with CyberKnife therapy. To the best of our knowledge, this is the first report on such treatment for choroidal hemangioma.
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Objective To evaluate the efficacy and safety of stereotactic body radiation therapy (SBRT) using Cyberknife in the treatment of patients with recurrent cholangiocellular carcinoma (RCC) after surgery.Methods Clinical data of 26 patients with recurrent RCC after surgery undergoing Cyberknife SBRT from 2010 to 2015 were retrospectively analyzed.The median recurrence time was 10 months (range 2.0-63.0 months) and the median tumor diameter was 2.8 cm (range 1.2-4.8 cm).The median prescription dose/fraction was 45 Gy/5f (range 40-50 Gy/3-8 f).The tumor progression was evaluated based on enhanced CT or MRI.Overall survival (OS),progression-free survival (PFS) and local control rate (LC) were analyzed by Kaplan-Meier method.Toxicity was assessed using the common terminology criteria for adverse events version 4.0.Results For the entire cohort,the median OS and PFS were 13.5 months and 6.5 months at a median follow-up of 29.3 months (range 2.1-62.0 months).The 1-and 2-year OS and PFS rates were 52％ and 21％ as well as 28％ and 15％,respectively.Among them,4 patients (4/26,15％) were recurrent in situ after SBRT.Three patients experienced grade Ⅲ adverse reactions including 1 case of gastrointestinal reaction,1 case of liver dysfunction and 1 case of biliary tract infection.Only 1 patient suffered from ≥ grade Ⅳ gastrointestinal bleeding during the advanced stage.Conclusions SBRT using Cyberknife is a safe and effective treatment for patients with recurrent RCC after surgery.The adverse reactions can be tolerated by patients.
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Objective To explore the clinical value of an auxiliary set-up method with fiducial markers and Synchrony tracking implanted in spine during Cyber-knife stereotactic radiotherapy by comparing the rotational setup errors between auxiliary setup with less than and more than three fiducial markers.Methods A total of 145 cases of tumor patients with fiducial tracking and Synchrony tracking were selected for radiotherapy,including 94 cases in the observation group (＜3 fiducial markers) and 51 cases in the control group (≥ 3 fiducial markers).Before treatment,one spinal alignment plan was added to all the cases in the observation group,and the rotation deviation of the selected spinal distance and the assisted spinal alignment correction of the fiducial marker tracking and the fiducial marker respiratory tracking were counted respectively,and the result of the rotation deviation calculated in the observation group and the control group were analyzed.Results Fiducial tracking spine auxiliary setup result:fiducial marks and selected the spine center distance ＜ 20,20-40,40-60,60-80 and ＞ 80 mm rotating statistical average deviation (0.494±0.350) °,(1.291±0.590) °,(1.705±0.739) °,(2.512±0.761) ° and (2.796± 1.081) °,respectively,rotate observation group and control group total deviation (1.742±0.784) °,(1.805±0.562) °,respectively.Synchrony tracking result in the above case rotation statistical average deviation was (1.190± 0.547) °,(1.956± 0.735) °,(2.141 ± 0.670) °,(2.957±0.648) ° and (4.027±0.695) °,respectively,while rotation total deviation in observation group and control group (2.619±0.906) °,(2.233 ±0.763) °,respectively.There was no significant difference in the rotation deviation between the assisted spinal set-fup and the calculation of rotation deviation between the fiducial tracking and the synchrony tracking (P ＞ 0.05).Conclusions In the fiducial tracking treatment,the range of rotation deviation for the spinal auxiliary set-up correction increases with the increase of the distance between the fiducial markers and the selected spinal center.When the distance between the fiducial marker and the selected spinal is less than 60 mm,the rotation deviation calculated by the spinal auxiliary setup has the same tumor rotation correction effect as that calculated by the fiducial markers.When less than 3 fiducial markers are available and the minimum distance between the fiducial marks and the center of the adjacent spine is relatively close (＜ 60 mm),the deviation of the rotation direction of the tumor can be calculated by adding the spinal auxiliary setup plan.
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Objective To evaluate the safety and effectiveness of ultra-hypofractionated stereotactic body radiotherapy in the treatment of prostate cancer.Methods A total of 26 patients with prostate cancer treated with Cyber-Knife from May 2010 to May 2018 were analyzed retrospectively.The median age of the patients was 69 years old (range,57 to 87).Ultra-hypofractionated radiotherapy was delivered in five fractions of 7.0-7.5 Gy for a total dose of 35.0-37.5 Gy.Androgen deprivation therapy (ADT) was administered in combination with the Cyber-Knife.The primary endpoints were radiation toxicity,PSA-response,local control and symptom alleviation,while the secondary endpoints were progression-free survival and overall survival.Results No graded ≥ 3 acute and late radiation toxicities occurred during follow-up.The acute toxicity of Grades 1 and 2 was 38.4％ and 19.2％,while the late toxicity of Grades 1 and 2 was 30.8％ and 3.8％,respectively.At a median follow-up of 22.44 months,for patients with localized stage,PSA level was decreased significantly after radiotherapy (Z =2.900,2.794,2.510,2.090,P＜0.05).However,there was no statistically significant difference for the metastatic group (P＞ 0.05).Conclusions Ultra-hypofractionated stereotactic body radiotherapy is a safe and effective treatment for patients with prostate cancer.
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Objective@#To improve synchrony tracking components of CyberKnife (tracking vest and tracking markers) and to analyze the clinical application value of the improved tracking components in CyberKnife treatment of thoracic and abdominal tumors.@*Methods@#The tracking apron was made of knitted four-side elastic spandex cloth and suture design of Velcro, which was used to stick the tracking markers on the chest and abdomen of patients. The tracking markers added a 2 cm thick light foam block to the bottom of the original markers, and then the hook face of the Velcro was fixed to the bottom of the light foam. The improved trace component (the improved component) and the original component (the vendor component) were applied to the lung tracking treatment model, and the manufacturer components were included in the reference group. Adoption of improved components into the observation group; 20 different types of respiratory waveforms were simulated and applied to the same mold plan. After treatment, the coverage rate, mean standard deviation, maximum standard deviation and the slope of XYZ-axis vs. R correlation graph were recorded. The relevant parameters of Synchrony model and wearable time of two components were compared, and the application significances of the improved tracking component in the breathing tracking process of the CyberKnife were evaluated.@*Results@#The maximum slope [median(interquartile range)] of XYZ-axis vs. R related graph in the reference group was 0.73 (3.89), 0.27 (0.49) and 0.34 (1.02), respectively. The maximum slope of XYZ-axis vs. R related graph in the observation group was 0.70 (2.78), 0.31 (0.30) and 0.36 (0.75), respectively. There was no statistically significant difference in the slope of XYZ-axis vs. R between the reference group and the observation group (all P > 0.05). There was no significant difference in the average standard error and maximum standard error between the reference group and the observation group [(1.7±0.4) mm vs. (1.7±0.5) mm, t=-0.382, P= 0.710; (2.0±0.6) mm vs. (1.7±0.5) mm, t=-0.877, P= 0.401], and the difference of the model coverage rate between the two groups was statistically significant [(48±18)% vs. (60±22)%, t= 2.762, P= 0.042]. The setup time of tracking components in the observation group was less than that in the reference group, and the difference was statistically significant [(44±24) s vs. (81±15) s, t=-4.310, P= 0.001].@*Conclusions@#The improved tracking components are comparable to the manufacturer tracking components in the standard error of the Synchrony model. The improved components shorten the wear time and appropriately improve the coverage of the Synchrony model.
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Objective@#To compare the dosimetrics of the plan target volume (PTV) and organs at risk (OARs) between two treatment planning approaches for patients with multiple brain metastases from non-small cell lung cancer on CyberKnife.@*Methods@#20 patients with multiple metastases from lung carcinoma were reviewed and analyzed, who had been treated by CyberKnife from December 2017 to December 2018. The CyberKnife stereotactic radiotherapy plans of the 20 cases were re-planed with single plan for multiple lesions and multiple plans per lesion. The dosimetry differences of PTV and OARs isodose disribution, conformity index (CI), total beam counts and total monitor units (MUs) were compared in the two types of plans.@*Results@#The two types of plans could satisfy over 95% PTV coverage of the prescription dose. The maximum and mean dose of normal brain adjacent to the PTV were reduced in multiple plan approach effectively. Moreover, the maximum and mean dose of OARs (brainstem) dropped by 1.62% and 5.57% (t=1.09, P<0.01) respectively. The number of treatment nodes and total MU declined by 4.63% (t=1.87, P<0.01)and 1.06% in multiple plan approach, which could significantly shorten the clinical treatment time. The differences in CI index between these two types of plans was of no statistical significance.@*Conclusions@#For patients with multiple brain metastases of similar diameter and volume from non-small cell lung cancer to be treated on CyberKnife, multiple plans per lesion could not only reduce dose to normal brain tissue and OARs, but also improve the treatment efficiency.
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Objective To compare the dosimetrics of the plan target volume (PTV) and organs at risk (OARs) between two treatment planning approaches for patients with multiple brain metastases from non-small cell lung cancer on CyberKnife.Methods 20 patients with multiple metastases from lung carcinoma were reviewed and analyzed,who had been treated by CyberKnife from December 2017 to December 2018.The CyberKnife stereotactic radiotherapy plans of the 20 cases were re-planed with single plan for multiple lesions and multiple plans per lesion.The dosimetry differences of PTV and OARs isodose disribution,conformity index (CI),total beam counts and total monitor units (MUs) were compared in the two types of plans.Results The two types of plans could satisfy over 95％ PTV coverage of the prescription dose.The maximum and mean dose of normal brain adjacent to the PTV were reduced in multiple plan approach effectively.Moreover,the maximum and mean dose of OARs (brainstem) dropped by 1.62％ and 5.57％ (t =1.09,P＜0.01) respectively.The number of treatment nodes and total MU declined by 4.63％ (t=1.87,P＜0.01) and 1.06％ in multiple plan approach,which could significantly shorten the clinical treatment time.The differences in CI index between these two types of plans was of no statistical significance.Conclusions For patients with multiple brain metastases of similar diameter and volume from non-small cell lung cancer to be treated on CyberKnife,multiple plans per lesion could not only reduce dose to normal brain tissue and OARs,but also improve the treatment efficiency.
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Objective@#To investigate the effectiveness and adverse effects of Cyberknife stereotactic body radiotherapy (SBRT) on liver metastases from PCa.@*METHODS@#From June 2009 to September 2016, we treated 20 cases of PCa liver metastases by Cyberknife SBRT, at a total dose of 36 (30－50) Gy, on 1－3 liver metastatic lesions, for 3－5 times, with a prescription isodose line of 70－92%. We assessed the therapeutic effect according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST), calculated the survival and disease-control rates using the Kaplan-Meier method, and analyzed the adverse events based on the National Cancer Institute Common Terminology Criteria for Adverse Events－Version 4.0 (CTCAE 4.0).@*RESULTS@#Of all the cases treated, complete response (CR) was found in 8 (40.0%), partial response (PR) in 9 (45.0%), stable disease (SD) in 2 (10.0%), and progressive disease (PD) in 1 (5.0%), with a local control rate (CR+PR) of 85.0% and a disease-control rate (CR+PR+SD) of 95.0%. Among the 14 patients with elevated PSA, 10 (71.4%) showed a significant decrease after treatment. The median follow-up time was 17 months, the 1- and 2-year survival rates were 85.0% and 15.0%, respectively, and the median survival time of the 20 patients was 16.5 months (95% CI: 12.12－22.88). Cyberknife SBRT was well tolerated in all the patients, with only a few mild adverse events (mainly grades 1 and 2 but no 4 and 5) during the whole course of treatment.@*CONCLUSIONS@#Cyberknife SBRT is safe and effective in the treatment of PCa liver metastases, with a high local control rate, and capable of reducing the PSA level and raising the long-term survival rate of the patients.
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Objective To study an accurate prediction algorithm for irregular respiratory movements,effectively compensate for the time delay of radiotherapy systems,so as to improve the target accuracy of imageguided tracking or gated radiotherapy for thoracic and abdominal tumors.Methods A prediction algorithm based on an adaptive neuro-fuzzy inference system (ANFIS) was proposed to precisely predict irregular respiratory motion.The ANFIS model structure adopted the position and velocity of respiratory motion as input parameters to construct an N×N fuzzy set that combines position and velocity,and to establish a training set through historical data.In the prediction,if the position or velocity in the latest input signal was out of the range of the training set,the position or velocity would be adjusted accordingly and treated as the input parameter of the ANFIS model for prediction.The ANFIS was evaluated using 20 cases of irregular respiratory clinical data from CyberKnife-treated thoracic and abdominal tumors patients.The accuracy of the four typical prediction algorithms,including ANFIS,neural network (NN),support vector machine (SVM),and CyberKnife Synchrony,was compared by retrospective offline analysis.Results The ANFIS algorithm showed better performance than NN,SVM and Synchrony in normalized root mean square error (nRMSE),the maximum error (Max),and the number of errors greater than 1 mm.Conclusions The accuracy and robustness of the ANFIS algorithm are superior to NN,SVM and CyberKnife Synchrony.The ANFIS can better predict irregular respiratory signals.