SU-D-211-03: An Automated Inverse Planning Optimization Approach for Single- Fraction and Fractionated Radiosurgery Using Gamma Knife Perfexion

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.

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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

Medical Physics ◽

10.1118/1.4815687 ◽

2013 ◽

Vol 40 (6Part31) ◽

pp. 517-517

Author(s):

D McDonald ◽

J Peng ◽

N Koch ◽

M Ashenafi ◽

D Jacqmin ◽

...

Keyword(s):

Gamma Knife ◽

Single Fraction ◽

Multiple Metastases ◽

Gamma Knife Perfexion

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Split Common Coincidence Point Problem: A Formulation Applicable to (Bio)Physically-Based Inverse Planning Optimization

Symmetry ◽

10.3390/sym12122086 ◽

2020 ◽

Vol 12 (12) ◽

pp. 2086

Author(s):

Charles E. Chidume ◽

Lois C. Okereke

Keyword(s):

Optimization Problem ◽

Coincidence Point ◽

Point Problem ◽

Optimization Approach ◽

Inverse Planning ◽

Clinical Criteria ◽

Planning Optimization ◽

Physically Based ◽

Treatment Plans ◽

Optimized Treatment

Inverse planning is a method of radiotherapy treatment planning where the care team begins with the desired dose distribution satisfying prescribed clinical objectives, and then determines the treatment parameters that will achieve it. The variety in symmetry, form, and characteristics of the objective functions describing clinical criteria requires a flexible optimization approach in order to obtain optimized treatment plans. Therefore, we introduce and discuss a nonlinear optimization formulation called the split common coincidence point problem (SCCPP). We show that the SCCPP is a suitable formulation for the inverse planning optimization problem with the flexibility of accommodating several biological and/or physical clinical objectives. Also, we propose an iterative algorithm for approximating the solution of the SCCPP, and using Bregman techniques, we establish that the proposed algorithm converges to a solution of the SCCPP and to an extremum of the inverse planning optimization problem. We end with a note on useful insights on implementing the algorithm in a clinical setting.

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Stereotactic radiosurgery versus stereotactic radiotherapy for patients with vestibular schwannoma: a Leksell Gamma Knife Society 2000 debate

Journal of Neurosurgery ◽

10.3171/jns.2000.93.supplement_3.0090 ◽

2000 ◽

Vol 93 (supplement_3) ◽

pp. 90-92 ◽

Cited By ~ 48

Author(s):

Mark E. Linskey

Keyword(s):

Gamma Knife ◽

Stereotactic Radiotherapy ◽

Three Dimensional ◽

Late Recurrence ◽

Vestibular Schwannomas ◽

Tumor Control ◽

Complication Rates ◽

Content Type ◽

Single Fraction ◽

Fine Print

✓ 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.

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Evaluating the impact of prescription isodose line on plan quality using Gamma Knife inverse planning

Journal of Applied Clinical Medical Physics ◽

10.1002/acm2.13388 ◽

2021 ◽

Author(s):

Qianyi Xu ◽

Gregory Kubicek ◽

David Mulvihill ◽

Warren Goldman ◽

Gary Eastwick ◽

...

Keyword(s):

Gamma Knife ◽

Plan Quality ◽

Inverse Planning ◽

The Impact ◽

Prescription Isodose

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Quality assurance for Gamma Knife Perfexion using the Exradin W1 plastic scintillation detector and Lucy phantom

Physics in Medicine and Biology ◽

10.1088/1361-6560/ab4ac3 ◽

2019 ◽

Vol 64 (22) ◽

pp. 225007 ◽

Cited By ~ 1

Author(s):

Francois Therriault-Proulx ◽

Ramiro Pino ◽

James N Yang ◽

A Sam Beddar

Keyword(s):

Quality Assurance ◽

Gamma Knife ◽

Scintillation Detector ◽

Plastic Scintillation ◽

Plastic Scintillation Detector ◽

Gamma Knife Perfexion

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Intracranial Metastatic Neuroblastoma Treated with Gamma Knife Stereotactic Radiosurgery: Report of Two Novel Cases

Case Reports in Neurological Medicine ◽

10.1155/2012/690548 ◽

2012 ◽

Vol 2012 ◽

pp. 1-4 ◽

Cited By ~ 1

Author(s):

Nathan C. Rowland ◽

Jennifer Andrews ◽

Daxa Patel ◽

David V. LaBorde ◽

Adam Nowlan ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Gamma Knife ◽

Treatment Options ◽

Tumor Burden ◽

Poor Survival ◽

Intracranial Metastasis ◽

Temporary Reduction ◽

Single Fraction ◽

Curative Therapy ◽

Gamma Knife Stereotactic Radiosurgery

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.

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