The measure analysis and QA system for gamma knife dose field and its pivotal techniques are described in this paper. By using our own measuring tools and analysis software, we have made a testing analysis about the HuaYuan Gamma Knife dose field with a satisfactory result.
Equipment Design ; Radiosurgery ; instrumentation ; methods ; Radiotherapy Dosage

OBJECTIVE: We investigated the effect of optimization in dose-limiting shell method on the dosimetric quality of CyberKnife (CK) plans in treating brain metastases (BMs).METHODS: We selected 19 BMs previously treated using CK between 2014 and 2015. The original CK plans (CKoriginal) had been produced using 1 to 3 dose-limiting shells : one at the prescription isodose level (PIDL) for dose conformity and the others at lowisodose levels (10–30% of prescription dose) for dose spillage. In each case, a modified CK plan (CKmodified) was generated using 5 dose-limiting shells : one at the PIDL, another at intermediate isodose level (50% of prescription dose) for steeper dose fall-off, and the others at low-isodose levels, with an optimized shell-dilation size based on our experience. A Gamma Knife (GK) plan was also produced using the original contour set. Thus, three data sets of dosimetric parameters were generated and compared.RESULTS: There were no differences in the conformity indices among the CKoriginal, CKmodified, and GK plans (mean 1.22, 1.18, and 1.24, respectively; p=0.079) and tumor coverage (mean 99.5%, 99.5%, and 99.4%, respectively; p=0.177), whereas the CKmodified plans produced significantly smaller normal tissue volumes receiving 50% of prescription dose than those produced by the CKoriginal plans (p < 0.001), with no statistical differences in those volumes compared with GK plans (p=0.345).CONCLUSION: These results indicate that significantly steeper dose fall-off is able to be achieved in the CK system by optimizing the shell function while maintaining high conformity of dose to tumor.
Brain ; Dataset ; Methods ; Neoplasm Metastasis ; Prescriptions ; Radiosurgery

In order to guarantee the safety and accuracy of the whole treating process as well as better link up of each section during the treatment, we did research in order to establish a project concerning the process quality control (PQC) of treating liver cancer with CyberKnife. From the safety and accuracy point of view, we divided the whole process of treating liver cancer with CyberKnife into ten links, i.e. the registration of patients' information, the im plantation of fiducial markers, fixation of body posture, CT localization, target delineation, design of the treatment plan, quality assurance in physics, implementation of the treatment plan, inspection on the correctness and data archiving. We analyzed the possible mistakes in each link and the consequences brought by them. To smoothly connect all the links, a special part "Attention" was added between every two links. Various wrong operations which may influence the safety and accuracy of treatment were illustrated, and the consequences brought by them were also ex plained. The "Attention" part among links offers important information for the next step, and gives us reminding and warnings. The project of quality control covers all the important links when treating liver cancer with Cy berKnife. It offers regulations, reminding and warning for us so that the safety and accuracy of treatment can be guaranteed, and the work of all staff could be closely connected.
Humans ; Liver Neoplasms ; surgery ; Quality Control ; Radiosurgery ; methods

Fourteen patients with pancreatic carcinoma were selected. Two treatment plans were designed for each patient, including gamma knife and Tomotherapy. The dose characteristics were evaluated by DVH and were compared. The results showed that the gamma knife plan had the higher maximal and mean target dose than Tomotherapy. Body gamma knife can increase the target dose significantly, and decrease the OAR dose. Tomotherapy had excellent dose-target conformality, and it can control doses of duodenum and stomach easily, but it had larger low dose region.
Humans ; Pancreatic Neoplasms ; radiotherapy ; Radiosurgery ; methods ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; methods

This paper presents a novel x-ray dose testing water tank used for the stereotactic radiation therapy system, including its constitution, structure and the method of using it. The water tank has a simple structure of inner and outer sleeves which are connected through a drowned pump and a water pipe in order to control the water level of the tank. The water tank featuring autoregulation and easy use is worthy of clinical application and popularization.
Equipment Design ; Radiosurgery ; instrumentation ; methods ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; instrumentation ; methods

PURPOSE: Tinnitus is a very common symptom of vestibular schwannoma, present in 45 to 80% of patients. We evaluated changes in tinnitus after translabyrinthine microsurgery (TLM) or gamma knife radiosurgery (GKS). MATERIALS AND METHODS: Among 78 patients with vestibular schwannoma who underwent TLM or GKS at Severance Hospital from 2009-2012, 46 patients with pre- or postoperative tinnitus who agreed to participate were enrolled. Pure tone audiometry, tinnitus handicap inventory (THI), visual analogue scale (VAS) scores for loudness, awareness, and annoyance were measured before and after treatment. Changes of THI and VAS were analysed and compared according to treatment modality, tumour volume, and preoperative residual hearing. RESULTS: In the TLM group (n=27), vestibulocochlear nerves were definitely cut. There was a higher rate of tinnitus improvement in TLM group (52%) than GKS group (16%, p=0.016). The GKS group had a significantly higher rate of tinnitus worsening (74%) than TLM group (11%, p<0.001). Mean scores of THI and VAS scores significantly decreased in the TLM group in contrast to significant increases in the GKS group. Tumor volume and preoperative hearing did not affect the changes in THI or VAS. CONCLUSION: GKS can save vestibulocochlear nerve continuity but may damage the cochlea, cochlear nerve and can cause worsening tinnitus. In cases where hearing preservation is not intended, microsurgery with vestibulocochlear neurectomy during tumor removal can sometimes relieve or prevent tinnitus.
Adult ; Female ; Humans ; Male ; Middle Aged ; Neuroma, Acoustic/*surgery ; Radiosurgery/*methods ; Tinnitus/*surgery ; Treatment Outcome

Humans ; Imaging, Three-Dimensional ; Neoplasms ; radiotherapy ; surgery ; Radiosurgery ; instrumentation ; methods ; Tomography, X-Ray Computed

Dural arteriovenous fistula (DAVF) have been treated by transarterial or transvenous embolization, surgery, and radiosurgery. Besides these treatment options, the external compression technique is a non-invasive, low-cost form of treatment. This article reports that a 60-year-old man with DAVF between multiple arterial branches and transverse/sigmoid sinus was treated by repeated external manual compression method.
Arteriovenous Fistula ; Central Nervous System Vascular Malformations* ; Humans ; Methods ; Middle Aged ; Radiosurgery ; Tinnitus*

Dural arteriovenous fistula (DAVF) have been treated by transarterial or transvenous embolization, surgery, and radiosurgery. Besides these treatment options, the external compression technique is a non-invasive, low-cost form of treatment. This article reports that a 60-year-old man with DAVF between multiple arterial branches and transverse/sigmoid sinus was treated by repeated external manual compression method.
Arteriovenous Fistula ; Central Nervous System Vascular Malformations* ; Humans ; Methods ; Middle Aged ; Radiosurgery ; Tinnitus*

Objective: To explore the safety and effectiveness of stereotactic body radiation therapy (SBRT) for oligometastases from colorectal cancer (CRC). Methods: This is a prospective, single-arm phase Ⅱ trial. Patients who had histologically proven CRC, 1 to 5 detectable liver or lung metastatic lesions with maximum diameter of any metastases ≤5 cm were eligible. SBRT was delivered to all lesions. The primary endpoint was 3-year local control (LC). The secondary endpoints were treatment-related acute toxicities of grade 3 and above, 1-year and 3-year overall survival (OS) and progression free survival (PFS). Survival analysis was performed using the Kaplan-Meier method and Log rank test. Results: Petients from 2016 to 2019 who were treated in Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College. Forty-eight patients with 60 lesions were enrolled, including 37 liver lesions and 23 lung lesions. Forty-six patients had 1 or 2 lesions, with median diameter of 1.3 cm, the median biologically effective dose (BED(10)) was 100.0 Gy. The median follow-up was 19.5 months for all lesions. Twenty-five lesions developed local failure, the median local progression free survival was 15 months. The 1-year LC, OS and PFS was 70.2% (95% CI, 63.7%~76.7%), 89.0% (95% CI, 84.3%~93.7%) and 40.4% (95%CI, 33.0%~47.8%). The univariate analysis revealed that planning target volume (PTV) and total dose were independent prognostic factors of LC (P<0.05). For liver and lung lesions, the 1-year LC, OS and PFS was 58.7% and 89.4% (P=0.015), 89.3% and 86.5% (P=0.732), 30.5% and 65.6% (P=0.024), respectively. No patients developed acute toxicity of grade 3 and above. Conclusion: SBRT is safe and effective treatment method for oligometastases from CRC under precise respiratory motion management and robust quality assurance.
Colorectal Neoplasms ; Humans ; Liver/pathology* ; Lung/pathology* ; Prospective Studies ; Radiosurgery/methods*