Ignition limit of a single-fraction gas suspension

1974 ◽  
Vol 10 (1) ◽  
pp. 76-80 ◽  
Author(s):  
M. A. Gurevich ◽  
G. E. Ozerova ◽  
A. M. Stepanov
Keyword(s):  
Ignition Limit ◽  
Gas Suspension ◽  
Single Fraction

Effect of burnout on the ignition limit of a monofractional gas suspension

1974 ◽  
Vol 10 (5) ◽  
pp. 596-603 ◽  
Author(s):  
M. A. Gurevich ◽  
G. E. Ozerova ◽  
A. M. Stepanov
Keyword(s):  
Ignition Limit ◽  
Gas Suspension

Concerning Stabilization of Heat Transfer of a Gas-Suspension Flow in a Tube

2003 ◽  
Vol 34 (7-8) ◽  
pp. 6 ◽  
Author(s):  
Yu. Ya. Pechenegov ◽  
O. Yu. Pechenegova
Keyword(s):  
Heat Transfer ◽  
Suspension Flow ◽  
Gas Suspension

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

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 90-92 ◽  
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.

scholarly journals Biologically effective dose correlates with linear tumor volume changes after upfront single-fraction stereotactic radiosurgery for vestibular schwannomas

2021 ◽  
Author(s):  
Constantin Tuleasca ◽  
Mohamed Faouzi ◽  
Philippe Maeder ◽  
Raphael Maire ◽  
Jonathan Knisely ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Effective Dose ◽  
Stereotactic Radiosurgery ◽  
Tumor Volume ◽  
Vestibular Schwannomas ◽  
Benign Tumors ◽  
Biologically Effective Dose ◽  
Volume Changes ◽  
Single Fraction

AbstractVestibular schwannomas (VSs) are benign, slow-growing tumors. Management options include observation, surgery, and radiation. In this retrospective trial, we aimed at evaluating whether biologically effective dose (BED) plays a role in tumor volume changes after single-fraction first intention stereotactic radiosurgery (SRS) for VS. We compiled a single-institution experience (n = 159, Lausanne University Hospital, Switzerland). The indication for SRS was decided after multidisciplinary discussion. Only cases with minimum 3 years follow-up were included. The Koos grading, a reliable method for tumor classification was used. Radiosurgery was performed using Gamma Knife (GK) and a uniform marginal prescription dose of 12 Gy. Mean BED was 66.3 Gy (standard deviation 3.8, range 54.1–73.9). The mean follow-up period was 5.1 years (standard deviation 1.7, range 3–9.2). The primary outcome was changes in 3D volumes after SRS as function of BED and of integral dose received by the VS. Random-effect linear regression model showed that tumor volume significantly and linearly decreased over time with higher BED (p < 0.0001). Changes in tumor volume were also significantly associated with age, sex, number of isocenters, gradient index, and Koos grade. However, the effect of BED on tumor volume change was moderated by time after SRS and Koos grade. Lower integral doses received by the VSs were inversely correlated with BED in relationship with tumor volume changes (p < 0.0001). Six (3.4%) patients needed further intervention. For patients having uniformly received the same marginal dose prescription, higher BED linearly and significantly correlated with tumor volume changes after SRS for VSs. BED could represent a potential new treatment paradigm for patients with benign tumors, such as VSs, for attaining a desired radiobiological effect. This could further increase the efficacy and decrease the toxicity of SRS not only in benign tumors but also in other SRS indications.

Single fraction prophylactic cranial irradiation for small cell carcinoma of the lung

1995 ◽  
Vol 34 (2) ◽  
pp. 132-136 ◽  
Author(s):  
A.E. Brewster ◽  
P. Hopwood ◽  
R. Stout ◽  
P.A. Burt ◽  
N. Thatcher
Keyword(s):  
Cell Carcinoma ◽  
Small Cell Carcinoma ◽  
Cranial Irradiation ◽  
Prophylactic Cranial Irradiation ◽  
Small Cell ◽  
Single Fraction

scholarly journals Small Particles in Gas Suspension

1984 ◽  
Vol 15 (11-12) ◽  
pp. 6-9 ◽  
Author(s):  
A. Schmidt-Ott ◽  
H. Burtscher
Keyword(s):  
Gas Suspension ◽  
Small Particles
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