In Vivo Dosimetry ; Radiotherapy Dosage ; Radiometry/methods* ; Electronics ; Radiotherapy, Intensity-Modulated/methods* ; Phantoms, Imaging ; Algorithms

Vascular damage is followed by vascular endothelial growth factor (VEGF) expression at high levels, which is an important mechanism for cerebral radiation necrosis (CRN) development. Antiangiogenic agents (Bevacizumab) alleviates brain edema symptoms caused by CRN through inhibiting VEGF and acting on vascular tissue around the brain necrosis area. Many studies have confirmed that Bevacizumab effectively relieves symptoms caused by brain necrosis, improves patients' performance status and brain necrosis imaging. Considering that the efficacy of antiangiogenic therapy is mainly related to the duration of drug action, low-dose antiangiogenic agents can achieve favorable efficacy. Prevention is the best treatment. The occurrence of CRN is associated with tumor-related factors and treatment-related factors. By controlling these factors, CRN can be effectively prevented.
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Angiogenesis Inhibitors/pharmacology* ; Bevacizumab/therapeutic use* ; Brain/metabolism* ; Consensus ; Humans ; Lung Neoplasms/drug therapy* ; Necrosis/etiology* ; Radiation Injuries/etiology* ; Vascular Endothelial Growth Factor A/metabolism*

Objective:To design a knowledge-based cervical cancer planning model and apply it to cases of endometrial cancer and rectal cancer in order to explore the generalization of the model.Methods:A total of 179 cases of pelvic regions with different prescribed doses of dual-arc volumetric modulated arc therapy clinical plans were collected, of which 99 cases of cervical cancer clinical plans with a prescribed dose of 50.4 Gy were used as the training set to establish the RapidPlan model, and the remaining clinical plans were divided into 4 validation groups with 20 cases in each group. The clinical plans for cervical cancer and endometrial cancer with a prescription dose of 50.4 Gy were named groups A and B, while the clinical plan for endometrial cancer and rectal cancer with a prescription dose of 45 Gy were named groups C and D. The model was used to redesign the clinical plans in the 4 groups and the automatic plans were obtained. The planning target volume (PTV) and organ at risk (OAR) dosimetry parameters were compared between automatic plans and clinical plans.Results:The conformity index (CI) of the automatic plans in the A, B, C, and D groups were equivalent to that of the clinical plans ( P>0.05). The homogeneity index (HI) and D2% of the automatic plans in groups A, B, and C were all lower than those in clinical plans(HI, Z=-3.248, -3.360, -2.329, P<0.05; D2%, Z=-2.987, -3.397, -2.442, P<0.05). The HI and D2% of the automatic plans in group D were similar those in the clinical plans ( P>0.05). While ensuring the PTV coverage, the average value of OAR dosimetry parameters in all automatic plans groups were lower than that of the clinical plans. Conclusions:The RapidPlan model established by the cervical cancer clinical plans can complete the automatic plan design for endometrial cancer and rectal cancer under different prescription doses, which preliminarily proves the possibility of the generalization of the RapidPlan model.

Brain metastasis of epidermal growth factor receptor (EGFR) sensitive mutations is a hot and difficult point in targeted era of non-small cell lung cancer (NSCLC) treatment, meanwhile it is also the central issue of controversy in the field of lung cancer treatment. Different results of different studies and different understanding of different disciplines, this field of treatment has been accompanied by different voices, patients without clinical symptoms can use targeted therapy first, and then start local radiotherapy with clinical symptoms or disease progression. It is a major model of the medical oncology. That is to say, taking symptoms and progress as indication and standard of local treatment intervention. In the absence of symptoms, local radiotherapy may increase patients' pain, which belongs to overtreatment. However, the perspective of radiotherapy is that brain metastases need to be treated clinically as early as possible, if not, it may affect the survival of patients. Early treatment of local lesions and increasing the depth of treatment are helpful to prolong the survival time of patients. This article refers to relevant literatures and summarizes the discussion from the perspective of pursuing the truth of disease treatment and problem solving in order to provide reference for patients' clinical practice.

Objective:To investigate the effect of Halo-Vest on the dose distribution of different radiotherapy techniques for primary cervical spine malignant tumors.Methods:Ten patients with primary cervical spine malignancies who underwent radiotherapy after Halo-Vest surgery were retrospectively studied. The IMRT and VMAT plans were designed on the contoured CT images including Halo-Vest delineations using Monaco planning system. The IMRT and VMAT plans with the same field parameters were duplicated to the CT images without the Halo-Vest delineations, and the dose distribution was recalculated. The dose distribution of the target, organs at risk and normal tissues was analyzed and compared for the plans with and without the Halo-Vest delineation.Results:For most dosimetric parameters of VMAT plans, the mean deviations induced by the Halo-Vest were less than 1%, except for PGTV 107%. Without Halo-Vest delineation, the mean maximum dose of spinal cord and spinal cord-PRV increased by 0.38 Gy and 0.42 Gy ( Z=-2.803, -2.803, P<0.05), respectively. The mean Dmean of spinal cord and spinal cord PRV increased by 0.35 Gy and 0.37 Gy, respectively ( Z=-2.703, -2.701, P<0.05). The maximum deviation observed in the mean V5, V30, and Dmean of mucosa, thyroid, parotid gland, mandible, mandibular joint, and normal tissues was 0.74%. For IMRT plans, larger dosimetric deviations than VMAT plans were observed in PTV and PGTV, most of which were more than 1.0% and the maximum deviation was 4.55%. The absence of Halo-Vest delineation increased the mean maximum dose of spinal cord and spinal cord-PRV by 0.48 Gy and 0.59 Gy ( P>0.05), respectively. The mean Dmean of spinal cord and spinal cord PRV increased by 0.57 Gy and 0.59 Gy, respectively ( Z=-2.293, -2.293, P<0.05). The maximum deviation of other organs at risk was 1.98%. Conclusions:There are no clinically significant dose differences for VMAT planning with or without Halo-Vest delineation on the CT images. But the dosimetric impact of absent or partial Halo-Vest delineation on IMRT planning is relatively large and should be considered.

Objective: To investigate clinicopathological features and prognostic factors of gastric neuroendocrine tumors (G-NEN). Methods: Clinical and pathological data of patients with G-NEN diagnosed by pathological examination in Chinese PLA General Hospital from January 2000 to June 2018 were retrospectively analyzed in this case-control study. Patients with complicated visceral lesions, other visceral primary tumors, mental disorders and incomplete clinicopathological data were excluded. Finally, 240 hospitalized patients who met the inclusion criteria were enrolled. Physical examination information, tumor characteristics and pathological characteristics of patients were summarized. The Cox regression models were used to analyze the risk factors affecting G-NEN and the survival conditions were described by Kaplan-Meier survival curves and log-rank test. Results: In 240 patients with G-NEN, the mean age was (60.3±10.1) years; 181 were male (75.4%) and 59 females (24.6%); mean tumor diameter was (4.2±2.8) cm; 51 cases (21.2%) were neuroendocrine tumor (NET), 139 cases (57.9%) neuroendocrine carcinoma (NEC), 50 cases (20.8%) mixed neuroendocrine carcinoma (MANEC); 28 cases (11.7%) were G1 low grades, 34 cases (14.2%) G2 medium grades, and 178 cases (74.2%) G3 high grades; tumor infiltration depth T1 to T4 were 44 cases (18.3%), 27 cases (11.2%), 60 cases (25.0%) and 109 cases (45.4%) respectively; 163 cases (67.9%) developed lymphatic metastasis and 46 patients (19.2%) distant metastasis; tumor stage from stage I to stage IV were 55 cases (22.9%), 42 cases (17.5%), 94 cases (39.2%) and 53 cases (22.1%) respectively. Of the 240 G-NEN patients, 223 cases (92.9%) were followed up. The median survival time of the patients was 39.2 (95% CI: 29.1 to 47.5) months. Univariate survival analysis showed that age ≥ 60 years, tumor diameter ≥ 4.2 cm, tumor grade G3, lymphatic metastasis, distant metastasis, and tumor stage III-IV were risk factors for G-NEN patients. Multivariate survival analysis revealed that lymphatic metastasis (HR=1.783, 95%CI: 1.007-3.155, P=0.047) and distant metastasis (HR=2.288, 95% CI: 1.307-4.008, P=0.004) were independent risk factors of the prognosis. Further analysis of the G3 subgroup of G-NEN showed that the 5-year survival rate of NET-G3 was 76.19%, which was significantly higher than that of NEC-G3 and MANEC-G3 (15.60% and 24.73%, P=0.012). Conclusions Most G-NEN patients are in advanced stage at diagnosis. Lymphatic metastasis and distant metastasis indicate poor prognosis. The prognosis of high proliferation NET-G3 patients is better as compared to those of NEC-G3 and MANEC-G3. This classification is worth further attention.

Objective To evaluate the efficacy and safety of CyberKnife stereotactic body radiation therapy (SBRT) in the treatment of hepatic hilar cancer.Methods A retrospective study was performed on the clinical data of 36 patients with hepatic hilar cancer who were admitted to our hospital and treated with CyberKnife SBRT from 2009 to 2015.In the 36 patients,37 lesions were found with tumor diameters ranging from 1.5 to 5.5 mm (median diameter 3 cm).The Synchrony respiratory tracking system was used for 21 lesions in 20 patients,while the XSight spinal tracking system was used for 16 lesions in 16 patients.Local progression was evaluated based on contrast-enhanced computed tomography and/or magnetic resonance imaging.The Kaplan-Meier method was used to calculate local control (LC) and overall survival (OS) rates,and the log-rank test was used for survival comparison and univariate prognostic analysis.Results The median follow-up time was 12.7 months.The 1-and 2-year postoperative LC rates were 90％ and 76％,respectively.The 1-year OS and progression-free survival (PFS) rates were 63％ and 39％,respectively.The median OS and PFS times were 15.2 and 10 months,respectively.The incidence of grade 3 adverse reactions was 11％.Conclusions The CyberKnife SBRT is a safe and effective way to treat hepatic hilar cancer.

Objective To investigate the utilization rate of gold fiducial markers and reasons for abandonment of gold fiducial markers in the CyberKnife VSI System, and to provide reference data for implantation of gold fiducial markers and radiotherapy planning. Methods From March to August,2017,a total of 47 patients had gold fiducial markers implanted or pasted. In those patients, 42 patients had gold fiducial markers implanted,including 32 receiving computed tomography(CT)-guided 3D-printing coplanar template assisted implantation, 1 receiving CT-guided 3D-printing non-coplanar template assisted implantation,1 receiving CT-guided implantation,and 8 receiving ultrasound-guided implantation. A total of 44 patients received the CyberKnife treatment, including 2 patients who failed to use gold fiducial markers and were treated with spine tracking instead and 3 patients missing the treatment for other reasons. The numbers of utilized and abandoned gold fiducial markers were recorded for calculation of the utilization and abandonment rates. The reasons for abandonment of gold fiducial markers were analyzed and classified. Results A total of 134 gold fiducial markers were implanted into or pasted to the 44 patients.In all the gold fiducial markers, 111 were utilized and 23 abandoned, yielding a utilization rate of 82.8% and an abandonment rate of 17.2%.The reasons for abandonment of gold fiducial markers included large rigidity error(26.1%), unqualified implanted fold fiducial markers(17.4%), displacement of gold fiducial markers(26.1%), and others(30.4%). Conclusions Compared with the CT-guided or ultrasound-guided implantation of gold fiducial markers, the CT-guided 3D-printing coplanar or non-coplanar template assisted implantation of gold fiducial markers requires only two puncture needles for each implantation and implants two gold fiducial markers by a single needle,which reduces the number of puncture needles,risk of puncture-induced injury,and incidence of complications after implantation. Not all the gold fiducial markers implanted by a variety of ways will be utilized. Some gold fiducial markers will be abandoned for different reasons,which should be taken into account during implantation of gold fiducial markers.

Spinal metastases may cause pain,pathological fracture and/or neurological symptoms.The most common treatment of spinal metastases is conservative therapy.Surgical intervention is necessary when there are pathological and/or neurological deficits.Total en bloc spondylectomy (TES) has lower local recurrence rate and may be applicable to a patient with single metastatic tumor and a long survival expectancy,While debulking surgery is less risky and higher recurrence rate.Conventional radiotherapy is a kind of effective supplement to reduce the local recurrence rate in spinal metastases.However,the local dose is often failed to reach the effective dose because of the close connection of tumor and spinal cord and it is less effective for relatively radioresistant histologies.With the development of radiotherapy technology,spinal radiotherapy has become increasingly accurate to avoid of spinal cord injury.In addition,conventional radioresistant tumors has become treatable with high-dose stereotactic body radiotherapy (SBRT).At the same time,SBRT is also an important basis for the implementation of separation surgery of spinal metastases.Separation surgery is to separate the tumor and dura and achieve circumferential decompression and stabilization through posterior approach.As a result,a high-dose SBRT can be performed because of the small interspace to protect the spinal cord,which greatly reduces the local recurrence rate.Compared with TES,separation surgery combined with high-dose radiotherapy not only reduces the difficulty of surgery,but also has a good local control rate,which is a relatively "minimally invasive" strategy.Separation surgery is particularly suitable for patients with high-grade epidural spinal cord compression and moderately sensitive or insensitive to radiotherapy.Although the concept of separation surgery has been proposed for several years,only a few applications have been reported in foreign literature and fewer in domestic literature.This article aims to summarize the relevant concepts and clinical applications of separation surgery in spine metastases and to provide a reference for the treatment of spinal metastases.

Objective To explore the symptom experience and nursing needs of spinal tumor patients with esophagus mucositis treated by Cyberknife. Methods From May to November 2017, we selected 9 spinal tumor patients treated by Cyberknife of Peking University Third Hospital as subjects by convenience sampling. All of the patients were interviewed by telephone. These data were analyzed with the phenomenological approach of the qualitative study. Results A total of four themes were refined including the esophagus mucositis-correlated symptoms were obvious during Cyberknife therapy, the esophagus mucositis during Cyberknife therapy affected the patients' psychology and treatment progress, the esophagus mucositis during Cyberknife therapy affected taking food, weight and nutrition of patients, patients thought that it was necessary for health care providers to provide patients the esophagus mucositis-correlated professional guidance and late follow-up during and after Cyberknife therapy. Conclusions The radioactive esophagus mucositis has a great influence on patients' physiology and psychology. Health care providersshould strengthen the related guidance and follow-up for patients during and after Cyberknife therapy.