Journal of radiosurgery and SBRT最新文献

Purpose: Establish the impact of iso-centre sequencing and unscheduled gaps in Gamma Knife® (GK) radiosurgery on the biologically effective dose (BED).

Methods: A BED model was used to study BED values on the prescription iso-surface of patients treated with GK Perfexion™ (Vestibular Schwannoma). The effect of a 15 min gap, simulated at varying points in the treatment delivery, and adjustments to the sequencing of iso-centre delivery, based on average dose-rate, was quantified in terms of the impact on BED.

Results: Depending on the position of the gap and the average dose-rate profiles, the mean BED values were decreased by 0.1% to 9.9% of the value in the original plan. A heuristic approach to iso-centre sequencing showed variations in BED of up to 14.2%, relative to the mean BED of the original sequence.

Conclusion: The treatment variables, like the iso-centre sequence and unscheduled gaps, should be considered during GK radiosurgery treatments.

Objective: To analyze and evaluate accuracy and efficiency of IGRT process for preoperative partial breast radiosurgery.

Methods: Patients were initially setup with skin marks and 5 steps were performed: (1) Initial orthogonal 2D kV images, (2) pre-treatment 3D CBCT images, (3) verification orthogonal 2D kV images, (4) treatment including mid-treatment 2D kV images (for the final 15 patients only), and (5) post-treatment orthogonal 2D kV or 3D CBCT images. Patient position was corrected at each step to align the biopsy clip and to verify surrounding soft tissue positioning.

Results: The mean combined vector magnitude shifts and standard deviations at the 5 imaging steps were (1) 0.96 ± 0.69, (2) 0.33 ± 0.40, (3) 0.05 ± 0.12, (4) 0.15 ± 0.17, and (5) 0.27 ± 0.24 in cm. The mean total IGRT time was 40.2 ± 13.2 minutes. Each step was shortened by 2 to 5 minutes with improvements implemented. Overall, improvements in the IGRT process reduced the mean total IGRT time by approximately 20 minutes. Clip visibility was improved by implementing oblique orthogonal images.

Conclusion: Multiple imaging steps confirmed accurate patient positioning. Appropriate planning and imaging strategies improved the effectiveness and efficiency of the IGRT process for preoperative partial breast radiosurgery.

Stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery have become widely used in both palliative and curative treatments for variety of primary and secondary malignancies. Although the indications and use of stereotactic techniques have increased substantially in the past decades, there been no studies to date analyzing public interest in these techniques. Using Google Trends (Google LLC, Mountain View, CA), four search terms ("SBRT," "stereotactic radiosurgery," "Gamma Knife" and "Cyberknife") were analyzed in the U.S. from January 2004 to June 2019. Each term was assigned a relative interest score based on frequency of searches. "SBRT" is becoming an increasingly popular search term, reaching peak interest in October 2018. Conversely, "stereotactic radiosurgery" and "Gamma Knife" radiosurgery initially had high interest, before declining over the past decade. "Cyberknife" was most popular in the mid-2000s but decreased steadily since that time. These trends were subsequently compared against PubMed publication data over the same time.

Superficial siderosis (SS) of the brain results from a chronic iron toxicity due to repeated microscopic leakage of blood products into the subarachnoid space. We report on Gamma Knife Radiosurgery (GKRS) associated worsening of superficial siderosis in a patient with skull-base tumor. A 73 year-old male patient presented with clumsiness and gait ataxia and was diagnosed with foramen magnum meningioma. He was also noted to have superficial siderosis involving the mainly the infratentorial compartment. After a thorough evaluation of craniospinal axis, no other cause of bleeding was identified. Patient was treated with the GKRS. After GKRS, there was an initial radiological and clinical worsening of SS starting at 6 months and peaking at 2 years. The disease stabilized and showed mild reduction at 3 years. GKRS lead to an initial progression of superficial siderosis. However, over a longer period, tumor control and improvement of the siderosis was observed.

Background: Cerebral arteriovenous malformations or angiomas are congenital vascular anomalies defined by abnormal arteriovenous shunt.

Materials and methods: We conducted a retrospective study between January 1992 and December 2010 at the Timone Hospital radiosurgery unit, 1557 patients were treated by radiosurgery for arteriovenous malformation of which 53 for thalamic localization (3,4%).

Results: The mean age was 35.8-/+16.6 years (4-75). 14 patients underwent pre-radiosurgical embolization (26.4%), discovery mode for 47 patients (88.7%) was haemorrhage. The average treatment volume was 1.43 cm³. The average RBAS score was 1.36. The average prescription to the 50% isodose envelope delivered was 22.9 +/-2.9 Gy (12-30), the median margin dose was 24 Gy. Our global obliteration rate after one or two procedures 66.7% for an average follow-up period of 56.7 months. We noted 3.9% of mortality, 5.9% of bleeding after procedure and 3.9% of radio-induced neurological deficit.

Conclusion: Radiosurgery became indispensable in the treatment of thalamic AVM even when there is a persistent risk of haemorrhage until total recovery.