• Radiation Oncology Journal
• /
• v.14 no.2
• /
• pp.149-158
• /
• 1996

Purpose : To get an accute steepness of dose gradients at outside the target volume in intracranial lesion and a less limitation of beam selection avoiding the high dose at normal brain tissue, this Photon Knife Radiosurgery System was developed in order to provide the three-dimensional dose distribution through the reconstruction of CT scan and the combined stereotactic trans-multiarc beam mode based on linear accelerator photon beam. Materials and methods : This stereotactic radiosurgery, Photon Knife based on linear accelerator photon beam was provided the non-coplanar multiarc and trans-multiarc irradiations. The stereotactic trans-multiarc beam mode can be obtained from the patient position in decubitus. This study has provided the 3-dimensional isodose curve and anatomical structures with the surface rendering technique. The dose distribution from the combined two trans-multiarcs (2M 2TM) was compared to that of four non-coplanar multiarcs (4M) with same collimator size of 25 mm in a diameter and total gantry movements. Results : In this study, it shows that the dose distributions of stereotactic beam mode are significantly depended on the selected couch and gantry angle in same collimator size. Practical dose distribution of combined stereotactic trans-multiarc beam has shown a more small rim thickness than that of the non-coplanar multiarc beam mode in axial, sagittal and coronal plane in our study. 3-Dimensional dose line displayed with surface rendering of irregular target shape is helpful to determine the target dose and to predict the prognosis in follow-up radiosurgery. Conclusions : 3-Dimensional dose line displayed with surface rendering of irregular target shape is essential in stereotactic radiosurgery. This combined stereotactic trans-multiarc beam has shown a less limitation of the selection couch and gantry beam angles for the target surrounding critical organs. It has shown that the dose distribution of combined trans-multiarc beam greatly depended on the couch and gantry angles. In our experiments, the absorbed dose has been decreased to $27%$ / mm in maximum at the interval of $50\%$ to $80\%$ of isodose line.

• Journal of Korean Neurosurgical Society
• /
• v.30 no.sup2
• /
• pp.294-299
• /
• 2001

Objectives : CT-guided stereotactic evacuation for spontaneous intracerebral hemorrhage can minimize the brain damage and can be performed safely and simply under local anesthesia. But that procedure is time consuming and has a risk of rebleeding because of the stress during head pin fixation. So authors describe easy and precise guidelines for FHA of putaminal hemorrhage without stereotactic instrument. Methods and Materials : We analyzed the data of 298 patients who underwent CT-guided stereotactic aspiration of putaminal hematoma in our hospital between January 1990 and December 2000. We divided the patients into three groups according to the location of hematoma : anterior portion, middle portion and posterior portion of putamen. Total number of catheters inserted into the hematoma were 345 and there were with regard to the direction and depth of catheters. Results : Proposed guidelines of catheter insertion to putaminal hemorrhage in our institution. 1) hematoma at the anterior portion of putamen ; Direction of catheter was the midpupillary line of the eye and the point intersecting a line drawn from the burr hole to a point between external auditory meatus(EOM) and 1cm posterior to EOM. Depth of catheter was 6-6.5cm. 2) hematoma at the middle portion of putamen ; Direction of catheter was the midpupillary line of the the eye and the point intersecting a line drawn from the burr hole to a point between 1cm and 2cm posterior to EOM. Depth of catheter was 6.5-7cm. 3) hematoma at the posterior portion of putamen ; Direction of catheter was 15 degree laterally from the midpupillary line of the eye and the point intersecting a line drawn from the burr hole to a point between 2cm and 3cm posterior to EOM. Depth of catheter was 7-7.5cm. We have performed FHA of putaminal hemorrhage in 48 cases according to this guideline. All catheter were inserted exactly at the center of hematoma and average operation time was about 30 minutes. Conclusion : Our proposed guidelines for putaminal hemorrhage are considered to be safe and simple method with similar accuracy and rapid decompression compared with traditional stereotactic method. Main advantages of this technique were unnecessity of stereotactic frame application and less time requirement for hematoma removal.

• 대한방사선치료학회:학술대회논문집
• /
• 1996.06a
• /
• pp.6-6
• /
• 1996

• Journal of Korean Neurosurgical Society
• /
• v.29 no.7
• /
• pp.954-958
• /
• 2000

In the removal of small subcortical lesion in the eloquent area like sensory-motor cortex, the prevention of neurologic deficit is important. We present our technique of identification of M-1, S-1 cortex in a case of subcortical granuloma located in sensorymotor cortex. To accurately localize mass, stereotactic craniotomy was planned. At the beginning of procedure, functional MRI of motor cortex was done with stereotactic headframe in place. Next, the stereotactic craniotomy about 4 cm was done under propofol anesthesia for cortical mapping. After reflection of dura, central sulcus was identified with phase-reversal response of intraoperative SEP(somatosensory evoked potential) of contralateral median nerve. Then the patient was awakened, and direct cortical stimulation was done. We observed the muscle contractions of elbow, hand and fingers and the paresthesia over forearm, hand, fingers on the M-1 and S-1 cortex. Through cortical mapping and stereotactic guidance, we concluded that the mass lie immediately posterior to central sulcus, then the mass was carefully removed through small transsulcal approach, opening about 1 cm of rolandic sulcus.

• Journal of Korean Neurosurgical Society
• /
• v.58 no.3
• /
• pp.217-224
• /
• 2015

Objective : To investigate the efficacy and safety of fractionated stereotactic radiosurgery for large brain metastases (BMs). Methods : Between June 2011 and December 2013, a total of 38 large BMs >3.0 cm in 37 patients were treated with fractionated Cyberknife radiosurgery. These patients comprised 16 men (43.2%) and 21 women, with a median age of 60 years (range, 38-75 years). BMs originated from the lung (n=19, 51.4%), the gastrointestinal tract (n=10, 27.0%), the breast (n=5, 13.5%), and other tissues (n=3, 8.1%). The median tumor volume was 17.6 cc (range, 9.4-49.6 cc). For Cyberknife treatment, a median peripheral dose of 35 Gy (range, 30-41 Gy) was delivered in 3 to 5 fractions. Results : With a median follow-up of 10 months (range, 1-37 months), the crude local tumor control (LTC) rate was 86.8% and the estimated LTC rates at 12 and 24 months were 87.0% and 65.2%, respectively. The median overall survival (OS) and progression-free survival (PFS) rates were 16 and 11 months, respectively. The estimated OS and PFS rates at 6, 12, and 18 months were 81.1% and 65.5%, 56.8% and 44.9%, and 40.7% and 25.7%, respectively. Patient performance status and preoperative focal neurologic deficits improved in 20 of 35 (57.1%) and 12 of 17 patients (70.6%), respectively. Radiation necrosis with a toxicity grade of 2 or 3 occurred in 6 lesions (15.8%). Conclusion : These results suggest a promising role of fractionated stereotactic radiosurgery in treating large BMs in terms of both efficacy and safety.

• Journal of Korean Neurosurgical Society
• /
• v.61 no.4
• /
• pp.525-529
• /
• 2018

Objective : To evaluate the efficacy of fractionated stereotactic radiosurgery (FSRS) performed using the Novalis $Tx^{(R)}$ system (BrainLAB AG, Feldkirchen, Germany; Varian Medical Systems, Palo Alto, CA, USA) for brain metastases. Methods : Between March 2013 and July 2016, 23 brain metastases patients were admitted at a single institute. Twenty-nine lesions too large for single session stereotactic radiosurgery or located in the vicinity of eloquent structures were treated by FSRS. Based on the results obtained, we reviewed the efficacy and toxicity of FSRS for the treatment of brain metastases. Results : The most common lesion origin was lung (55%) followed by breast (21%). Median overall survival was 10.0 months (95% confidence interval [CI], 4.9-15.0), and median progression-free survival was 10.0 months (95% CI, 2.1-13.9). Overall survival rates at 1 and 2 years were 58.6% and 36.0%, respectively. Local recurrence and neurological complications affecting morbidity each occurred in two cases. Conclusion : FSRS using the $Novalis-Tx^{(R)}$ system would appear to be an effective, safe noninvasive treatment modality for large and eloquently situated brain metastases. Further investigation is required on a larger number of patients.

• The Journal of Korean Society for Radiation Therapy
• /
• v.9 no.1
• /
• pp.25-28
• /
• 1997

With the advances in radiation therapy technology and equipment, the need for more accurate and safer radiation delivery to the target region has been continuously growing. Stereotactic Radiosurgery(SRS) is a good example of $^{\ast}Accuracy^{\ast}$ but has a substantial risk of causing severe late neurological damages. Fractionated Stereotactic Radiation Therapy(FSRT) is a modification of SRS enabling conventional fractionation with maintaining accuracy using noninvasive and relocatable frame. Verification of mechanical accuracy in FSRT has been done according to the manufacture's recommendations using RLPP, LTLF, and Depth-helmet. In order to reinforce this, we have developed additional novel verification procedure using Linac-grams with the Angiolocalizer attached on the GTC frame, which are then digitized into the planning software(X-Knife) to generate the three dimensional coordinates for cmoparison. This method has been successful in such ways that the anatomical landmarks are identifiable on the Linac-gram films and that the serial comparisons of the stereotactic coordinates of the isocenter are possible with more certainty a along the FSRT course than before.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.17
• /
• pp.7595-7597
• /
• 2015

Background: The aim of this study was to evaluate the effect of whole brain radiotherapy (WBRT) combined with streotactic radiosurgery versus stereotactic radiosurgery (SRS) alone for patients with brain metastases. Materials and Methods: This was a retrospective study that evaluated the results of 46 patients treated for brain metastases at Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital, Radiation Oncology Department, between January 2012 and January 2015. Twenty-four patients were treated with WBRT+SRS while 22 patients were treated with only SRS. Results: Time to local recurrence was 9.7 months in the WBRT+SRS arm and 8.3 months in SRS arm, the difference not being statistically significant (p=0.7). Local recurrence rate was higher in the SRS alone arm but again without significance (p=0,06). Conclusions: In selected patient group with limited number (one to four) of brain metastases SRS alone can be considered as a treatment option and WBRT may be omitted in the initial treatment.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.13
• /
• pp.5279-5284
• /
• 2015

Background: The study analyzed the long term clinical outcomes of pituitary adenoma cases treated with the first Thailand installation of a dedicated Linac-based stereotactic radiation machine (X-Knife). Materials and Methods: A retrospective review of 115 consecutive pituitary adenoma patients treated with X-Knife at the Faculty of Medicine, Ramathibodi Hospital, Bangkok, Thailand from 1997 to 2003 was performed. Stereotactic radiosurgery (SRS) was selected for 21 patients (18%) including those with small tumors (${\leq}3cm$) located ${\geq}5mm$. from the optic apparatus, whereas the remaining 94 patients (82%) were treated with fractionated stereotactic radiotherapy (FSRT). Results: With a median follow-up time of 62 months (range, 21-179), the six-year progression free survival was 95% (93% for SRS and 95% for FSRT). The overall hormone normalization at 3 and 5 years was 20% and 30%, respectively, with average time required for normalization of approximately 16 months for SRS and 20 months for FSRT. The incidence of new hypopituitarism was 10% in the SRS group and 9% in the FSRT group. Four patients (5%) developed optic neuropathy (1 in the SRS group and 3 in the FSRT group). Conclusions: Linac-based SRS and FSRT achieved similar high local control rates with few complications in pituitary adenoma cases. However, further well designed, randomized comparative studies between SRS versus FSRT particularly focusing on hormone normalization rates are required.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.8
• /
• pp.3561-3566
• /
• 2014

Background: Recurrent nasopharyngeal carcinoma (NPC) after previous radiotherapy is challenging. There is no standard approach for salvage treatment. Here we present toxicity and treatment results for recurrent NFC patients who underwent fractionated stereotactic radiotherapy (FSRT) as second line radiotherapy (RT). Materials and Methods: Between April 2009 and July 2012, 24 patients, with a male to female ratio of 3:1, were treated with CykerKnife$^{(R)}$ FSRT for recurrent NFC in our institution. Seven out of 24 patients had metastatic recurrent disease. Median age was 53 years (range, 20-70 years). Initial RT dose was 70Gy. The time period between initial RT and FSRT was a median of 33.2 months. The median prescription dose for FSRT was 30Gy (range, 24-30 Gy) in a median of 5 fractions (range, 4-6). Results: The median follow-up for all patients was 19.5 months (IQR: 12.2.-29.2 months). The locoregional control; progression free survival and overall survival (OS) rates for 1-, 2- and 3-year were 64%, 38%, 21%; 60%, 30%, 17% and 83%, 43%, 31%, respectively. Median OS for the entire cohort was 22 months (95% CI: 16.5-27.5). On multivariate analysis recurrent tumor stage was the only prognostic factor for OS (p=0.004). One patient exhibited grade III temporal lobe necrosis. One died because of grade IV mucositis and overlapping infection. Conclusions: The treatment of recurrent NPC is controversial. Fractionated stereotactic radiotherapy is promising. However, the published trials are heterogeneous with respect to the selection criteria and treatment details. Prospective studies with long term follow-up data are warranted.