TH-A-137-05: Evaluation of Dose Spillage From the Gamma Knife Perfexion Vs Volumetric Modulated Arc Radiosurgery When Treating Multiple Metastases in a Single Fraction

2013 ◽  
Vol 40 (6Part31) ◽  
pp. 517-517
Author(s):  
D McDonald ◽  
J Peng ◽  
N Koch ◽  
M Ashenafi ◽  
D Jacqmin ◽  
...  
2010 ◽  
Vol 113 (Special_Supplement) ◽  
pp. 222-227
Author(s):  
Ryan Smith ◽  
Kris A. Smith ◽  
Christopher A. Biggs ◽  
Adrienne C. Scheck

Object The goal of this study was to develop an assay that makes possible the assessment of the glioma cell response to single-fraction high-dose Gamma Knife surgery. In this assay, the isolation of radioresistant cell subpopulations facilitates mechanistic studies of radioresistance. Methods A tissue-equivalent paraffin phantom with an aperture capable of holding an Opticell cell culture cassette was developed for treatment with the Leksell Gamma Knife model C. A second apparatus, which the authors also created, uses the manufacturer-supplied polystyrene phantom, thereby allowing this assay to be performed in the Leksell Gamma Knife Perfexion. After treatment, the cells were morphologically assessed to determine their response to radiation treatment. Two specific parameters were used to determine radiosensitivity: 1) the diameter of the clearing zone, defined as the central region of cell death; and 2) the number of surviving colonies within this central high-dose clearing zone. Results Radioresistance was compared in 2 different cell lines from glioblastomas. The first cell line, ME, was established from a primary tumor before its treatment, and the second cell line, DIV, was established from a tumor that recurred after treatment with chemotherapy and fractionated radiotherapy. The ME cell line had the most robust response to radiosurgery, as characterized by a consistently larger clearing zone (28.33 ± 1.1 mm). In contrast, the clearing zone produced when the DIV cell line was used was 24.0 ± 1 mm, indicating an approximate response difference of 5 Gy. The mean number of surviving colonies within the clearing zone for the ME cell line was 1.33 ± 1 compared with that for the DIV cell line, which was 66.67 ± 2. Conclusions The authors developed a biological dosimeter to model the response of cells from glioblastomas to single-fraction high-dose radiation. This system also allows the identification and isolation of radioresistant cells.


2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 90-92 ◽  
Author(s):  
Mark E. Linskey

✓ By definition, the term “radiosurgery” refers to the delivery of a therapeutic radiation dose in a single fraction, not simply the use of stereotaxy. Multiple-fraction delivery is better termed “stereotactic radiotherapy.” There are compelling radiobiological principles supporting the biological superiority of single-fraction radiation for achieving an optimal therapeutic response for the slowly proliferating, late-responding, tissue of a schwannoma. It is axiomatic that complication avoidance requires precise three-dimensional conformality between treatment and tumor volumes. This degree of conformality can only be achieved through complex multiisocenter planning. Alternative radiosurgery devices are generally limited to delivering one to four isocenters in a single treatment session. Although they can reproduce dose plans similar in conformality to early gamma knife dose plans by using a similar number of isocenters, they cannot reproduce the conformality of modern gamma knife plans based on magnetic resonance image—targeted localization and five to 30 isocenters. A disturbing trend is developing in which institutions without nongamma knife radiosurgery (GKS) centers are championing and/or shifting to hypofractionated stereotactic radiotherapy for vestibular schwannomas. This trend appears to be driven by a desire to reduce complication rates to compete with modern GKS results by using complex multiisocenter planning. Aggressive advertising and marketing from some of these centers even paradoxically suggests biological superiority of hypofractionation approaches over single-dose radiosurgery for vestibular schwannomas. At the same time these centers continue to use the term radiosurgery to describe their hypofractionated radiotherapy approach in an apparent effort to benefit from a GKS “halo effect.” It must be reemphasized that as neurosurgeons our primary duty is to achieve permanent tumor control for our patients and not to eliminate complications at the expense of potential late recurrence. The answer to minimizing complications while maintaining maximum tumor control is improved conformality of radiosurgery dose planning and not resorting to homeopathic radiosurgery doses or hypofractionation radiotherapy schemes.


2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Nathan C. Rowland ◽  
Jennifer Andrews ◽  
Daxa Patel ◽  
David V. LaBorde ◽  
Adam Nowlan ◽  
...  

Intracranial metastasis of neuroblastoma (IMN) is associated with poor survival. No curative therapy for the treatment of IMN currently exists. Unfractionated radiotherapy may be beneficial in the treatment of IMN given the known radiosensitivity of neuroblastoma as well as its proclivity to metastasize as discrete lesions. We present two patients with IMN treated with Gamma Knife stereotactic radiosurgery (SRS). Single-fraction radiotherapy yielded temporary reduction of tumor burden and stability of disease in both patients. SRS may be a useful palliative tool in the treatment of IMN and expands the overall treatment options for this disease.


2020 ◽  
Vol 1528 ◽  
pp. 012028
Author(s):  
I N Pranditayana ◽  
A R. Setiadi ◽  
M M Ramadhan ◽  
D Tandian ◽  
S A. Pawiro

2017 ◽  
Vol 16 (6) ◽  
pp. 893-899
Author(s):  
Wade P. Smith ◽  
Lori A. Young ◽  
Mark H. Phillips ◽  
Michael Cheung ◽  
Lia M. Halasz ◽  
...  

2010 ◽  
Vol 37 (6Part23) ◽  
pp. 3305-3305
Author(s):  
M Mamalui-Hunter ◽  
T Zhao ◽  
R Drzymala

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