Dosimetric comparison of two radiotherapy treatment planning approaches for multiple brain metastases from non-small cell lung cancer on CyberKnife / 中华放射医学与防护杂志

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.

Dosimetric comparison of two radiotherapy treatment planning approaches for multiple brain metastases from non-small cell lung cancer on CyberKnife / 中华放射医学与防护杂志

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.

Preliminary clinical study on treatment of prostate cancer with Cyber-Knife / 中华放射医学与防护杂志

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.

A dosimetric analysis of lung tissue in early stage non-small cell lung cancer patients treated by Cyberknife radiotherapy / 中华放射医学与防护杂志

Objective To analyze the radiation dose to the normal lung tissue of patients with early stage of non-small cell lung cancer treated by Cyberknife. Methods A retrospective analysis was conducted by summarizing the treatment plans of 264 patients with early stage non-small cell lung cancer from January 2011 to December 2013 in Tianjin Medical University Cancer Institute and Hospital. Sorted by the tumor volumes and locations, the Cyberknife plans were evaluated by means of dose volume histograms ( DVH) , homogeneity indexes ( HI) , percentage volumes receiving at least x Gy ( Vx ) of dose, i. e. , V5 , V10 , V20 , and V30 of the ipsilateral and contralateral lungs. For the tumors approximate to the hilus, the contralateral lungs were included in the optimization process, and the dose-volume metrics were analyzed for the contralateral and bilateral lungs. Results For the tumors close to the chest wall, V5≥(15. 21 ± 3. 12)％ in ipsilateral lung tissue and V5≥(1. 34 ± 0. 67)％ in contralateral lung tissue were observed. For the tumors near the hilus, V5≥(39. 4 ± 11. 90) ％ in ipsilateral lung tissue and V5≥(1. 48 ± 0. 34) ％ in contralateral lung tissue were observed. The irradiated volume ratios of both ipsilateral and contralateral lung tissue increased with the enlargement of tumor sizes. After including the contralateral lung tissue into the optimization, the irradiated volume ratios of the contralateral and bilateral lung tissue (V5,V10) decreasedsignificantly(t=2.44,4.81,3.53,3.17,P<0.05). Conclusions Higherriskof radiation injury in both ipsilateral and contralateral lung tissue can be expected for tumors near the hilus than near the chest wall. After including contralateral lung tissue into the planning optimization, lower dose to the contralateral and whole lung tissue was achieved, indicating a better protection of normal lung tissue.

Clinical observation on the treatment efficacy of Cyberknife for iliac lymph node metastasis / 中华放射医学与防护杂志

Objective To evaluate the response rate and efficacy of Cyberknife in the treatment of iliac lymph node metastases (ILNM).Methods Twenty-two patients with 27 ILNM were treated by Cyberknife from May 2010 to May 2016.Tumor volume range from 0.88 to 125.66 cm3 (median 18.87 cm3).The total doses ranged from 21 to 51 Gy (median 39 Gy) and biological effective doses from 35.7 to 100 Gy (median 72.6 Gy) in 3-8 fractions (median 5).Sixty-four percent to eighty-two percent (median 72％) isodose line covered planning target.The survival rates were calculated by Kaplan-Meier method and compared with Log-rank test.Results Follow-up time ranged from 8 to 97 months (median 33 months).The complete response,partial response,stable disease and progression disease rates were 37％,48％,7.5％,48％,respectively.In addition,effective rate was 92.5％.Overall survival range from 4 to 68 months (median 21 months).The 1-,2-,3-year local control rate was all 90.6％ and the survival rates were 78.8％,60.6％ and 43.3％,respectively.Adverse reactions after treatment were gastrointestinal reactions such as nausea,vomiting,fatigue.The chemotherapy before Cyberknife helped to improve overall survival.The patients with backache or edema of lower extremity got rapid relief after treatment.Conclusion The treatment of ILNM with Cyberknife has provided a high response rate with minimal side effects.Cyberknife is a safe and effective local treatment method for ILNM.

Clinical efficacy of CyberKnife radiotherapy for locally advanced pancreatic carcinoma / 中华放射肿瘤学杂志

Objective To assess the efficacy and safety of CyberKnife radiotherapy in the treatment of locally advanced pancreatic carcinoma. Methods The data of 59 patients with locally advanced pancreatic carcinoma who were treated with CyberKnife radiotherapy from 2006 to 2014 were retrospectively analyzed. The tumor volume ranged from 13?? 0 cm3 to 125?? 1 cm3 with a median value of 27?? 1 cm3 . A dose of 35?50 Gy (median value= 45 Gy) in 3?8 fractions (median value = 5 fractions) was prescribed. The tumor progression was evaluated based on computed tomography. The overall survival (OS) and local progression?free survival ( LPFS) rates were calculated using the Kaplan?Meier method. Results The 1?and 2?year sample sizes were 26 and 17, respectively. The 1?and 2?year OS rates were 54% and 35%, respectively, while the 1?and 2?year LPFS rates were 91% and 70%, respectively. The median OS and LPFS times were 12?? 5 and 10?? 9 months, respectively. The overall incidence of grade 1?2 acute and late gastrointestinal toxicity was 61%. One patient with grade 3 late gastrointestinal toxicity had incomplete intestinal obstruction. Conclusions CyberKnife radiotherapy can achieve excellent treatment outcomes and mild complications in the treatment of locally advanced pancreatic carcinoma.

Effects of preoperative parecoxib on interleukin 6 and postoperative analgesia for mastectomy / 临床麻醉学杂志

Objective To investigate the effects of preoperative parecoxib on the levels of inter-leukin 6 (IL-6)and postoperative analgesia for breast surgery.Methods Sixty breast cancer patients undergoing mastectomy were randomly divided into two groups:parecoxib group (group P)and con-trol group (group C),n=30 in each group.All patients received sevoflurane and fentanyl anesthesia. Group P was injected parecoxib 40 mg at 10 minutes before induction of anesthesia,meanwhile group C was injected saline 5 ml.All patients received postoperative patient-controlled intravenous analgesia (PCIA)with fentanyl.VAS scores for pain were assessed at postoperative 2,4,8,12,24 hours. The serum levels of IL-6 were measured by ELISA at 10 minutes before induction,4 h,8 h,and 24 h after surgery.Results Group P had lower VAS scores than group C at 2-12 h after surgery (P <0.05).Compared with 10 minutes before induction,the levels of IL-6 increased significantly at post-operative 4,8,24 h in two groups (P<0.01),while group P had lower levels of IL-6 than group C (P <0.01).Conclusion Preoperative administration of parecoxib has a stronger analgesic effect in breast cancer patients after mastectomy,and decreases the levels of IL-6.

Robotic stereotactic irradiation and reirradiation for spinal metastases: safety and efficacy assessment / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Spine is the most common site of bone metastases in patients with cancer. Conventional external beam radiotherapy lacks precision to allow delivery of large fraction radiation but simultaneously limit the dose to spinal cord. The purpose of this study was to evaluate the safety and efficacy of CyberKnife(®) radiation therapy for spinal metastases.</p><p><b>METHODS</b>Seventy-three lesions in 62 patients treated with CyberKnife radiotherapy from September 2006 to June 2010 for spinal metastases were retrospectively reviewed. Thirteen tumors in 12 patients had received prior radiation. Patients were followed clinically and radiographically for at least 12 months or until death. In all patients, the spinal cord and thecal sac were contoured for dose-volume constraints, and maximum doses to 0.1, 0.5, 1, 2, and 5-ml volumes were analyzed.</p><p><b>RESULTS</b>Using the CyberKnife System, 20-48 Gy in one to five fractions for unirradiated patients, and 21-38 Gy in one to five fractions for the previously irradiatied patients, were delivered. Median 2-Gy normalized Biological Equvalent Dose (nBED) of unirradiated targets and irradiated targets were 49.6 Gy10/2 (range, 31.25-74.8 Gy10/2) and 46.9 Gy10/2 (range, 29.8-66 Gy10/2), respectively. With a median follow-up of 9.4 months (range, 2.5-45 months), twenty-nine patients (46.7%) were alive, whereas the others died of progressive disease. Fifty-six patients (93.3%) reported complete or partial reduction of pain after CyberKnife radiotherapy at one-month follow-up, 17 patients (28.3%) reported some degree of pain relief after first fraction of the treatment course. Two patients experienced local recurrence at fifth and ninth months post-radiotherapy. Median maximum nBED for spinal cord and thecal sac of naive targets were 68.6 Gy2/2 (range, 8.3-154.5 Gy2/2) and 83.5 Gy2/2 (range, 10.5-180.5 Gy2/2), respectively. Median maximum nBED for spinal cord and thecal sac for the re-irradiated targets were 58.6 Gy2/2 (range, 17.7-140 Gy2/2) and 70.5 Gy2/2 (range, 21.7-141.3 Gy2/2), respectively. No patient developed radiation related myelopathy during the follow-up period.</p><p><b>CONCLUSION</b>Cyberknife radiotherapy is clinically effective and safe for spinal metastases, even in previously irradiated patients.</p>

Evaluation of extra absorbed dose generated by image guided system of the Cyberknife / 中华放射肿瘤学杂志

Objective To evaluate quantitatively the extra absorbed dose generated by image guided system of the Cyberknife.Methods The exposure parameters and the average frequency of images acquisition during the treatments with G3 Cyberknife in 300 cases with various tumor locations and tracking modes were collected for analysis ;The measurements of the absorbed doses in the phantom with 5 points after single exposure generated by image guided system in various exposure parameters were performed with equipment of phantom CIRS Model 002LFC and 002 PRA with ion chamber PTW30010 included.Based on the data we collected andmeasured,the conclusion of how much extra absorbed dose generated by image guided system of Cyberknife the patients received during Cyberknife treatments was drawn.Results With an average fractions of 3.94(the median was 4),the average exposure frequency was 36.5 times for static tracking per patient per fraction,while it was 49.2 times for dynamic tracking.The experimental results with various exposure parameters,positions and tissue densities showed that the minimum absorbed dose after single exposure was 0.5 μGy,while the maximum was 385 μGy.Conclusions The image guided system of the Cyberknife can induce quite low absorbed dose in patient,while providing all three types of image guided function.

Impacts of different tracking methods on short-term therapeutic effect of cyberknife in treatment of lung cancer / 中华放射肿瘤学杂志

Objective To investigate the impacts of fiducial tracking and X-sight tracking on the short-term therapeutic effect of cybernikife in the treatment of lung cancer.Methods Retrospective analysis was performed on 64 lung cancer patients (72 lesions),including 40 primary tumor patients (41 lesions) and 24 metastatic tumor patients (31 lesions),who were treated with cyberknife.Fiducial tracking was used for 45 lesions,while X-sight tracking was used for 27 lesions.The planning target volume was covered by 70％-94％ (median 80％) isodose contour.The irradiation dose was 60 Gy/3 fractions.The relationship between short-term therapeutic effect and tracking method was determined.Results Overall,the lesions undergoing fiducial tracking showed significantly higher response rate than those undergoing X-sight tracking (93％ vs.74％,x2 =6.84,P=0.033),and so was in lower lung lesions (15％ vs.7％,x2 ＝7.18,P=0.028).But the two tracking methods achieved similar effects in upper lung lesions (28％ vs.12％,x2 =2.36,P =0.310).In the lesions with treatment volumes smaller than 15 cm3,the fiducial tracking achieved significantly higher response rate than the X-sight tracking (25 ％ vs.12％,x2 =6.53,P =0.038),but the two tracking methods achieved similar effects in the lesions with treatment volumes not smaller than 15 cm3 (17％ vs 8％,x2 =1.57,P =0.460).Overall,the lesions undergoing X-sight tracking had significantly highertreatment failure rate than fiducial tracking (1 9 ％ vs.2 ％,x2 =6.33,P =0.021).Conclusions Different tracking methods may lead to different therapeutic effects of cyberknife in the treatment of lung cancer,which are related to lesion location and treatment volume.

Value of local progression-free survival for evaluating local outcome of peripheral lung cancer treated by cyberknife / 中华放射肿瘤学杂志

Objective To investigate the value of local progression-free survival (LPFS) for evaluating the local long-term outcome of peripheral lung cancer treated by cyberknife.Methods Retrospective analysis was performed on the clinical records of 81 cyberknife-treated lung cancer patients (90 foci),including 43 primary lung cancer patients (43 foci) and 38 metastatic lung cancer patients (47 foci).Of all the patients,58(63 foci) were treated at a dose of 60 Gy/3 fractions (20 Gy/fraction),and 23 (27 foci) at a dose of 54 Gy/3 fractions (18 Gy/fraction).The short-term treatment outcome and LPFS were used as the indices for observation;a logistic regression was used for analyzing the predictive value of LPFS for local long-term treatment outcome.Results After the evaluation of short-term treatment outcome,63％ of all the foci needed further evaluation.As the follow-up lasted,the number of foci which needed further evaluation decreased,most rapidly during 0.5-2 years after treatment.Re-evaluation results had predictive value for the treatment outcome in the subsequent follow-up,but the predictive value declined as the follow-up lasted.Conclusions LPFS is a recommendable index for evaluating the local outcome of primary or metastatic lung cancer treated by cyberknife,and it also has predicative value for local long-term treatment outcome.

Impact of number of implanted fiducials on image target localization accuracy / 中华放射肿瘤学杂志

Objective To find a proper number of implanted fiducials in order to reconcile both more accurate image tacking and less pain for the patients.Methods The phantom was made of two parts of different materials.The inner part was a ball-cube phantom developed by Accuray Corporation, which could be regarded as a rigid body, with 5 fiducials inside using as the reference to align the whole phantom in the experiment.The outer part was made of additional silicone rubber with two components to simulate soft tissue as a non-rigid body, which was implanted with 8 fiducials inside.All combinations of different number of fiducials were tracked to aquire the target location information, which were then compared with the reference position that was set by the inner 5 fiducials to obtain the deviations of the translation and the rotation parameters.Thus the impact of the number of fiducials on image target localization accuracy could be analyzed easily.Results When 4 fiducials are used for tracking, the decline of translation and rotation errors for every fiducial is largest (0.086 mm and 0.033°).The translation error was decreased by 0.343 mm from 1 to 4 fiducials, while by only 0.077 mm from 4 to 8 fiducials;the same decline was observed for rotation errors (0.131° for 3 to 4 fiducials , and 0.09° for 4 to 8 fiducials , respectively) .Conclusions When 4 fiducials are used for tracking, the decline of errors for every fiducial is maximum.When one more fiducial is adding, the image target localization accuracy can be enhanced obviously from 1 to 4 fiducials, but not as obvious for more than 4 fiducials.

An initial report of cyberknife radiosurgery treatment in early stage lung cancer / 中华放射肿瘤学杂志

Objective To study the efficacy and toxicity of the cyberknife in the treatment of medically inoperable patients with early stage lung cancer. Methods From September 2006 to July 2007,17 patients with clinical stage Ⅰ a- Ⅰ b lung cancer were treated with cyberknife at Tianjin Cancer Hospital. Of the 11 patients receiving CT guided biopsy, 3 were squamous cell cancer and 8 were adenocarcinoma. Six patients refused intrusive operation and were diagnosed by PET-CT scan. All patients were medically inoperable evaluated by a thoracic surgeon. The PTV = GTV + 3 ～ 5 mm, and the median volume of PTV was 36 cm3 (6-82 cm3 ). The median total prescription dose was 50 Gy(45-60 Gy) at 3-5 fractions. Results The median follow-up time was 7 months (3-11 months). All the patients finished the treatment and were alive by the last follow-up. Slight fatigue was the most common complain. Evaluated by CT scan, 13 were complete response and 4 were partial response. No recurrence, progression or distant metastasis occured. There were 3 patients with grade Ⅰ granulocytopenia,3 grade Ⅰ pneumonitis and 1 grade Ⅱ pneumonitis. Conclusions The cyberknife radiosurgery treatment in early stage lung cancer shows a high rate of local control and minimal toxicity. Long time follow-up is necessary to evaluate the survival data and late toxicity.

Long-term outcomes of intracavitary hyperthermia in combination with radiotherapy for locally advanced uterine cervical cancer / 中华放射肿瘤学杂志

Objective To evaluate the long-term clinical efficacy and toxicities of combined intracavitary hyperthermia and radiotherapy fur locally advanced uterine cervical cancer. Methods 310 patients with locally advanced uterine cervical cancer were assigned into intracavitary hyperthermia + radiotherapy group(TRT, 181 patients) and external-beam radiotherapy + traditional intracavitary radiation group (RT,129 patients). The external-beam radiotherapy were given with 60Co γ-my or 6-8 MV X-ray in traditional fractionation. In TRT group,radiotherapy was 40 Gy using the anterior-posterior pelvic fields and additional 20-25 Gy using the lateral fields. Hyperthermia was delivered by the 915 MHz microwave hyperthermia device within 15-60 min after external radiotherapy for 10-12 times(40 min each time,1-2 times per week). The temperature of tumor surface was 46-47℃. In the RT group, the external-beam radiotherapy of 40 Gy was delivered using the anterior-posterior pelvic fields. The intracavity radiotherapy of radium was delivered before 1989 ,with 50 mg radium in the vagina and 30 mg in uterine cavity for 24 hours ,weekly for 3 times to a total dose of 7200 mg·h. After 1989,intraeavity radiotherapy of 192Ir was delivered to a total dose of 30-36 Gy to point A in 5-6 Gy fractions,2 fractions per week. Results The 5-year survival of patients in TRT group and RT group was 67.4% versus 52.1% for stage Ⅱ disease (χ2=7.55,P=0.006), and 60.0% vemus32.3% forstage Ⅲ (χ2=7.06,P=0.007) . The 10-year survival was46.5% versus42.6% for stage Ⅱ (χ2=3.90,P=0.058), and 43.7% versus 20.6% for stage Ⅲ(χ2=17.28,P=0.000). Cox regression analysis showed that the tumor stage(P=0.023) and intracavitary hyperthermia( P=0.019) were prognostic factors. According to the RTOG criteria, the rate of mild to moderate late side effects of rectum and bladder in TRT and RT group was 17.7% and 33.1%, respectively (χ2=9.18, P=0.002). Rectovaginal fistula was developed in5 patients(3.9% ) in RT group and I patient (0.6%) in TRT group(χ2= 4.38,P=0.036). Conclusions The long-term survival of patients with stage Ⅲ uterine cervical cancer is better of TRT group than RT group. The TRT is well tolerated and the late toxicity rate is obviously low. It is necessary to carry out large randomized clinical trials to confirm these outcomes.

Simulation of SAR and temperature distribution for tumor RF thermotherapy with double-frequencies and double-plates / 生物医学工程学杂志

The model establishment and numerical simulation of specific absorption rate (SAR) and the unsteady-state temperature distribution for radio frequency (RF) thermotherapy with double-frequencies and double-plates are presented in this paper. The model can correctly reflect the attenuation of electromagnetic wave in the biotissue. The variation of perfusion with temperature and the lower perfusion in tumor tissue are fully considered in the simulation of unsteady-state temperature profiles. Also presented are detailed analyses and discussions on the characteristics of SAR and temperature profiles, and the effects of the plates location and power as well as of the perfusion on the depth of effective treatment.

The simulation of SAR and temperature distribution and parameters analysis for tumor RF thermotherapy / 生物医学工程学杂志

In this paper are reported the model establishment and numerical simulation of specific absorption rate(SAR) and the unsteady temperature distribution for the non-invasive tumor RF thermotherapy. The model can correctly reflect the attenuation of electromagnetic wave in the biotissue, the variation of perfusion with temperature and lower perfusion of the tumor tissue are fully considered in the simulation. These measures made simulation results more close to the clinical results. Also presented in the paper are detailed analyses and discussions on the characteristics of SAR of electromagnetic energy and the temperature profiles, the effects of the frequency and the perfusion on the depth for effective treatment. The simulation results are of great significance for directing the clinical application of tumor RF thermotherapy.

Development of thermal dosimeter for hyperthermia / 医疗卫生装备

To realize temperature real-time control in microwave heat treatment, this paper presents a new type of thermal dosimeter on hyperthermia. The sign of temperature is extracted by mini-thermal-electronic-couple transducer, amplification circuit and main magnifier. The bond of temperature controlling and thermal therapy is achieved, the experimental prototype of thermal dosimeter equipment is developed and clinical experiment scheme is designed. The whole system is simple in structure, high in efficiency and reliability.