Yokohama CyberKnife Center

Asahi, Japan

Yokohama CyberKnife Center

Asahi, Japan
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Kawaguchi K.,Tsurumi University | Sato K.,Yokohama CyberKnife Center | Horie A.,Tsurumi University | Iketani S.,Toshiba Corporation | And 4 more authors.
Radiation Oncology | Year: 2010

Background: The aim of this study is to examine the effect of stereotactic radiosurgery (SRS) in the treatment of advanced, recurrent lesions for head and neck carcinoma both with and without lymph node involvement.Methods: Between April 2006 and July 2007, 22 patients (mean age 67 years) with advanced, recurrent head and neck carcinoma were treated with stereotactic radiosurgery. All of the patients except one had biopsy confirmed disease prior to stereotactic radiosurgery. Patients included 3 rT2, 8 rT3, and 9 rT4; 8 of the patients had lymph node metastases. Marginal SRS doses were 20-42 Gy delivered in two to five fractions. Starting one month after SRS, all patients received S-1 oral chemotherapy for one year.Results: At an overall median follow-up of 24 months (range, 4-39 months), for the 14 locally recurrent patients without lymph node metastases, 9 patients (64.3%) had a complete response (CR), 1 patient (7.1%) had a partial response (PR), 1 patient (7.1%) had stable disease (SD), and 3 patients (21.4%) had progressive disease (PD). For the 8 patients with lymph node metastases, 1 patient with a single retropharyngeal (12.5%) had CR; the remaining 7 patients (87.5%) all progressed. Nine patients have died from their cancer. The overall actuarial 2-year survival for the patients with and without lymph node metastases is 12.5% and 78.6%, respectively.Conclusions: These results show the benefit of stereotactic radiosurgery salvage treatment for advanced, recurrent lesions, without lymph node metastases in previously irradiated head and neck cancer. © 2010 Kawaguchi et al; licensee BioMed Central Ltd.


Iwata H.,Nagoya City University | Baba Y.,Okayama Kyokuto Hospital | Shibamoto Y.,Yokohama CyberKnife Center
Neuro-Oncology | Year: 2011

The aim was to evaluate the clinical outcome of hypofractionated stereotactic radiotherapy (SRT) with CyberKnife for nonfunctioning pituitary adenoma. From October 2000 to March 2009, 100 patients with nonfunctioning pituitary adenoma were treated with hypofractionated SRT. Forty-three patients were male, and 57 were female. The patient's ages ranged from 16 to 82 years (median, 59 years). Five patients were medically inoperable, and 1 refused surgery; the remaining 94 were recurrent cases or those receiving postoperative adjuvant SRT. No patients had a history of previous cranial radiotherapy. Tumor volume ranged from 0.7 to 64.3 mL (median, 5.1 mL). The marginal doses were 17.0 to 21.0 Gy for the 3-fraction schedule and 22.0 to 25.0 Gy for the 5-fraction schedule. Toxicities were evaluated with the Common Terminology Criteria for Adverse Events version 4.0. The median follow-up period for living patients was 33 months (range, 18-118.5 months). The 3-year overall survival and local control rates were 98% and 98%, respectively. In-field and out-field tumor regrowth were observed in 3 and 2 patients, respectively. Transient cyst enlargement occurred in 3 cases. A post-SRT grade 2 visual disorder occurred in 1 patient. Symptomatic post-SRT hypopituitarism was observed in 3 of 74 patients who had not received hormone replacement therapy after surgery. CyberKnife SRT involving 21 Gy in 3 fractions or 25 Gy in 5 fractions is safe and effective for surgical treatment of nonfunctioning pituitary adenoma. Hypofractionated SRT appears useful for protecting the visual nerve and neuroendocrine function, especially for tumors located near the optic pathways and large tumors. © 2011 The Author(s).


Kawaguchi K.,Tsurumi University | Sato K.,Yokohama CyberKnife Center | Yamada H.,Tsurumi University | Horie A.,Tsurumi University | And 6 more authors.
Journal of Oral and Maxillofacial Surgery | Year: 2012

Purpose: The purpose of this study was to investigate the effect of stereotactic radiosurgery on local control and organ preservation in cases of primary head and neck cancer. Patients and Methods: In this retrospective study, 14 patients with a mean age of 73 years were treated between March 2006 and September 2007 with stereotactic radiosurgery for the management of primary head and neck cancer. The patients had biopsy confirmation of disease before treatment and all patients were confirmed with squamous cell carcinoma. The staging consisted of T2 (5 cases), T3 (3 cases), T4 (6 cases), N0 (13 cases), and N1 (1 case). Marginal doses were 3,500 to 4,200 cGy in 3 or 5 fractions. The outcome was assessed according to Response Evaluation Criteria in Solid Tumors criteria based on magnetic resonance imaging and positron emission tomography/computed tomography. Results: Significant tumor reduction was noted at the third month of follow-up with 5 complete responses and 9 partial responses. At a mean follow-up of 36 months (range, 14-40 mo) the local control and overall survival rates were 71.4% (10/14) and 78.6% (11/14), respectively. Conclusions: These results show the feasibility of using stereotactic radiosurgery for primary head and neck cancer and its potential benefit in local control and organ preservation. © 2012 American Association of Oral and Maxillofacial Surgeons.


Iwata H.,Nagoya City University | Inoue M.,Yokohama CyberKnife Center | Yokota N.,Hamamatsu University School of Medicine | Sato K.,Red Cross | Shibamoto Y.,Nagoya City University
Radiotherapy and Oncology | Year: 2012

Purpose: To evaluate the clinical outcome of stereotactic reirradiation using the CyberKnife system for recurrent nasal or paranasal carcinoma. Materials and methods: From May 2005 to February 2010, 51 patients with local recurrence of nasal or paranasal carcinoma were reirradiated using CyberKnife. Tumor volume ranged from 3.1 to 204.9 ml (median, 33.8). The previous conventional radiotherapy dose ranged from 40 to 70 Gy (median, 60). The median follow-up period for surviving patients was 21 months (range, 12-52). The marginal doses were 20-41.5 Gy in 1-5 fractions (35 Gy). Toxicities were evaluated with the Common Terminology Criteria for Adverse Events version 4.0. Results: The median overall survival and local control periods after reirradiation were 14.5 and 9.5 months, respectively. The 1-year survival and local control rates were 67% and 62%, respectively. Grade 3 or higher adverse events were observed in 23%. Grade 4 dermatitis and soft tissue necrosis were observed in 2 and 1 patients who had received trimodality combination therapy as their previous treatment, respectively. Conclusions: Salvage stereotactic reirradiation using CyberKnife is feasible and effective for the local recurrence of nasal and paranasal carcinomas. To further improve treatment outcomes, exploration of better planning and dose fractionation, as well as combination chemotherapy would be worthwhile. © 2012 Elsevier Ireland Ltd. All rights reserved.


Murai T.,Nagoya City University | Murai T.,Yokohama Cyberknife Center | Ogino H.,Proton Therapy | Manabe Y.,Nagoya City University | And 6 more authors.
Clinical Oncology | Year: 2014

Aims: To evaluate the toxicity and efficacy of fractionated stereotactic radiotherapy (FSRT) with doses of 18-30Gy in three fractions and 21-35Gy in five fractions against large brain metastases. Materials and methods: Between 2005 and 2012, 61 large brain metastases (≥2.5cm in maximum diameter) of a total of 102 in 54 patients were treated with FSRT as a first-line therapy. Neurological symptoms were observed in 47 of the 54 patients before FSRT. Three fractions were applied to tumours with a maximum diameter ≥2.5cm and <4cm, and five fractions were used for brain metastases ≥4cm. After ensuring that the toxicities were acceptable (≤grade 2), doses were escalated in steps. Doses to the large brain metastases were as follows: level I, 18-22Gy/three fractions or 21-25Gy/five fractions; level II, 22-27Gy/three fractions or 25-31Gy/five fractions; level III, 27-30Gy/three fractions or 31-35Gy/five fractions. Level III was the target dose level. Results: Overall survival rates were 52 and 31% at 6 and 12 months, respectively. Local tumour control rates of the 102 total brain metastases were 84 and 78% at 6 and 12 months, respectively. Local tumour control rates of the 61 large brain metastases were 77 and 69% at 6 and 12 months, respectively. Grade 3 or higher toxicities were not observed. Conclusions: The highest dose levels of 27-30Gy/three fractions and 31-35Gy/five fractions seemed to be tolerable and effective in controlling large brain metastases. These doses can be used in future studies on FSRT for large brain metastases. •With Cyberknife, 61 large brain metastases in 54 patients were treated.•Three levels of prescribed dose were used with the dose escalation design.•Dose levels of 27-30Gy/3 fractions, 31-35Gy/5 fractions were target dose levels.•The median survival was 6 months. Unacceptable toxicities were not observed.•The target dose levels can be used for large brain metastases. © 2013 The Royal College of Radiologists.


Iwata H.,Nagoya City University | Iwata H.,Yokohama CyberKnife Center | Tatewaki K.,Yokohama CyberKnife Center | Inoue M.,Yokohama CyberKnife Center | And 7 more authors.
Journal of Neuro-Oncology | Year: 2012

Craniopharyngiomas are slow-growing tumors found in the suprasellar region, with especially high incidence in Japanese children. Due to the location, proximity and adhesiveness of the tumor to adjacent critical structures, these tumors remain a significant clinical challenge. The purpose of this study was to evaluate the clinical outcome of single and hypofractionated stereotactic radiotherapy (SRT) with CyberKnife for craniopharyngioma. Forty-three patients (21 men and 22 women; median age 44 years; range 3-85 years) were treated at two institutions. Three cases were treated in a single fraction to a marginal dose of 13-16 Gy. The other 40 cases were treated in 2-5 fractions to a marginal dose of 13-25 Gy. Tumor volumes ranged from 0.09 to 20.8 cm 3 (median 2.0 cm 3). Toxicities were evaluated with the Common Terminology Criteria for Adverse Events version 4.0. The median follow-up period was 40 months (range 12-92 months). The 3-year overall survival and local control rates were 100 and 85%, respectively. In-field cyst enlargement was observed in 9 patients. These tumors had significantly larger volumes (mean 6.9 cm3; 95% confidence interval, CI, 2.8-10.9 cm 3) than the 34 controlled tumors (2.9 cm 3; CI 1.5-4.3 cm 3) (P = 0.02). Out-field tumor regrowth was observed in 4 patients. No radiationinduced symptomatic visual disorder or brain necrosis was observed. Hypopituitarism was observed in only 1 patient. Single and hypofractionated SRT using CyberKnife produced high tumor control rates with minimal complications. Hypofractionated SRT may be useful for protecting the visual nerve and neuroendocrine function, especially for tumors located near the optic pathways and for large tumors. © 2011 Springer Science+Business Media, LLC.


Sato K.,Yokohama CyberKnife Center
Japanese Journal of Clinical Radiology | Year: 2010

Objective of this report is to analyze CyberKnife (CK) treatment for 80 patients with neck lymph node metastasis. Of them, 64 patients underwent previous radiation therapy. Control rate at one year point was 81%, Death of disease was 80%. There was no major adverse event except for one case with rupture of internal carotid artery.


PubMed | Red Cross, Nagoya City University, Suzukake Central Hospital, Proton Therapy and Yokohama CyberKnife Center
Type: Journal Article | Journal: Japanese journal of radiology | Year: 2016

Recurrent ependymomas were retreated with stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT). The efficacy, toxicities, and differences between SRS and FSRT were analyzed.Eight patients with recurrent ependymomas fulfilling the criteria described below were evaluated. Inclusion criteria were: (1) the patient had previously undergone surgery and conventional radiotherapy as first-line treatment; (2) targets were located in or adjacent to the eloquent area or were deep-seated; and (3) the previously irradiated volume overlapped the target lesion.FSRT was delivered to 18 lesions, SRS to 20 lesions. A median follow-up period was 23 months. The local control rate was 76 % at 3 years. No significant differences in local control were observed due to tumor size or fractionation schedule. Lesions receiving >25 Gy/5 fr or 21 Gy/3 fr did not recur within 1 year, whereas no dose-response relationship was observed in those treated with SRS. No grade 2 toxicity was observed.Our treatment protocol provided an acceptable LC rate and minimal toxicities. Because local recurrence of tumors may result in patient death, a minimum dose of 21 Gy/3 fr or 25 Gy/5 fr or higher may be most suitable for treatment of these cases.


PubMed | Yokohama CyberKnife Center
Type: Journal Article | Journal: Journal of applied clinical medical physics | Year: 2015

The accuracy of the CyberKnife Synchrony Respiratory Tracking System (SRTS) is considered to be patient-dependent because the SRTS relies on an individual correlation between the internal tumor position (ITP) and the external marker position (EMP), as well as a prediction method to compensate for the delay incurred to adjust the position of the linear accelerator (linac). We aimed to develop a system for obtaining pretreatment statistical measurements of the SRTS tracking error by using beams eye view (BEV) images, to enable the prediction of the patient-specific accuracy. The respiratory motion data for the ITP and the EMP were derived from cine MR images obtained from 23 patients. The dynamic motion phantom was used to reproduce both the ITP and EMP motions. The CyberKnife was subsequently operated with the SRTS, with a CCD camera mounted on the head of the linac. BEV images from the CCD camera were recorded during the tracking of a ball target by the linac. The tracking error was measured at 15 Hz using in-house software. To assess the precision of the position detection using an MR image, the positions of test tubes (determined from MR images) were compared with their actual positions. To assess the precision of the position detection of the ball, ball positions measured from BEV images were compared with values measured using a Vernier caliper. The SRTS accuracy was evaluated by determining the tracking error that could be identified with a probability of more than 95% (Ep95). The detection precision of the tumor position (determined from cine MR images) was < 0.2 mm. The detection precision of the tracking error when using the BEV images was < 0.2mm. These two detection precisions were derived from our measurement system and were not obtained from the SRTS. The median of Ep95 was found to be 1.5 (range, 1.0-3.5) mm. The difference between the minimum and maximum Ep95 was 2.5mm, indicating that this provides a better means of evaluating patient-specific SRTS accuracy. A suitable margin, based on the predicted patient-specific SRTS accuracy, can be added to the clinical target volume.


PubMed | Yokohama CyberKnife Center, Nagoya City University, Proton Therapy, Suzukake Central Hospital and Miyakojima IGRT Clinic
Type: Journal Article | Journal: Technology in cancer research & treatment | Year: 2016

We investigated the dose uncertainty caused by errors in real-time tracking intensity-modulated radiation therapy (IMRT) using the CyberKnife Synchrony Respiratory Tracking System (SRTS). Twenty lung tumors that had been treated with non-IMRT real-time tracking using CyberKnife SRTS were used for this study. After validating the tracking error in each case, we did 40 IMRT planning using 8 different collimator sizes for the 20 patients. The collimator size was determined for each planning target volume (PTV); smaller ones were one-half, and larger ones three-quarters, of the PTV diameter. The planned dose was 45 Gy in 4 fractions prescribed at 95% volume border of the PTV. Thereafter, the tracking error in each case was substituted into calculation software developed in house and randomly added in the setting of each beam. The IMRT planning incorporating tracking errors was simulated 1000 times, and various dose data on the clinical target volume (CTV) were compared with the original data. The same simulation was carried out by changing the fraction number from 1 to 6 in each IMRT plan. Finally, a total of 240 000 plans were analyzed. With 4 fractions, the change in the CTV maximum and minimum doses was within 3.0% (median) for each collimator. The change in D99 and D95 was within 2.0%. With decreases in the fraction number, the CTV coverage rate and the minimum dose decreased and varied greatly. The accuracy of real-time tracking IMRT delivered in 4 fractions using CyberKnife SRTS was considered to be clinically acceptable.

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