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Benoit Pirotte, Serge Goldman, Nicolas Massager, Philippe David, David Wikler, Maurice Lipszyc, Isabelle Salmon, Jacques Brotchi and Marc Levivier

.591 × 2.591 mm pixels and 6.75 mm thick; thus, the precision of the target definition corresponds to a volume a 45 µl. 27 Analysis of Stereotactic PET Scans and Target Definition The surgical planning began with an analysis of the PET scans. Given that this series represents an evaluation of Met-PET studies and based on our previous experience, we started with an independent analysis of the FDG-PET scans for each patient. 27, 28 The Met-PET scans were analyzed thereafter. Areas of abnormal metabolism used for target selection were either zones of FDG or Met

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Michael Torrens, Caroline Chung, Hyun-Tai Chung, Patrick Hanssens, David Jaffray, Andras Kemeny, David Larson, Marc Levivier, Christer Lindquist, Bodo Lippitz, Josef Novotny Jr., Ian Paddick, Dheerendra Prasad and Chung Ping Yu

incorrect or incomplete. It is hoped that this consensus will inspire discussions leading to more general agreement on terminology between technologies within the radiosurgical community. Meanwhile, those members submitting papers to the International Leksell Gamma Knife Society will be expected to conform to these standards. This report covers the following areas: Target delineation and volume measurement Dose prescription and measurement (target) Dose definition in areas of risk The committee wishes to acknowledge the input, comments, and advice of the many people who

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Benoît Pirotte, Serge Goldman, Olivier Dewitte, Nicolas Massager, David Wikler, Florence Lefranc, Nordeyn Oulad Ben Taib, Sandrine Rorive, Philippe David, Jacques Brotchi and Marc Levivier

T he increasing availability and routine application of image-guided neurosurgery, or neuronavigation, improves the accuracy and safety of neurosurgical interventions. It may help to optimize tumor resection by using contours representing tumor limits and brain structures defined on anatomical imaging such as CT scanning and MR imaging. Indeed, most gliomas will have a definitive volume based on either Gd-DTPA– or non–Gd-DTPA–enhanced scans. For example, LGGs will have a volume defined by imaging based on their T 2 -weighted or FLAIR MR imaging volume. A

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Constantin Tuleasca, Jean Régis, Elena Najdenovska, Tatiana Witjas, Nadine Girard, Thomas Bolton, Francois Delaire, Marion Vincent, Mohamed Faouzi, Jean-Philippe Thiran, Meritxell Bach Cuadra, Marc Levivier and Dimitri Van de Ville

—with MR signature volume 1 year after SRS thalamotomy (SRS-T) for ET. This particular aspect could be of potential clinical interest, as recent studies have shown a correlation between this volume and clinical improvement, in the sense that higher volumes are related to better therapeutic responses. 8 , 39 Moreover, in a small number of cases, higher MR reactions can be accompanied by edema and/or symptoms, with a need for further corticosteroid therapy. There are no data in the current literature with regard to factors potentially correlating with these MR reactions

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Marc Levivier, David Wikler Jr., Nicolas Massager, Philippe David, Daniel Devriendt, Jose Lorenzoni, Benoit Pirotte, Françoise Desmedt, Stephane Simon Jr., Serge Goldman, Paul Van Houtte and Jacques Brotchi

, provided that they are easily obtained in a routine manner, render this approach possible and open the way to a wide range of applications in the neurosurgical management of brain tumors, such as biopsy, open neurosurgery, and radiosurgery. Radiosurgery may play a role as an adjuvant therapy for gliomas; 21, 22 however, their infiltrative nature makes accurate delineation difficult and the volume for treatment is limited. The use of well-defined metabolic data provided by PET studies may therefore be helpful in dose planning and radiosurgery of gliomas. In this paper

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Marc Levivier, David Wikier, Serge Goldman, Philippe David, Thierry Metens, Nicolas Massager, Massimo Gerosa, Daniel Devriendt, Françoise Desmedt, Stephane Simon, Paul Van Houtte and Jacques Brotchi

, accurate delineation is difficult and the possibility for accurate determination of the appropriate target volume for treatment is limited. Moreover, in patients who have undergone surgery, CT and MR imaging may not define tumor recurrence accurately. The use of PET, an imaging technique providing metabolic data, may add another layer of sophistication to the use of radiosurgery in the treatment of gliomas and metastases. Indeed, in our experience using PET in stereotactic conditions for the management of brain tumors, we found that it provides independent metabolic

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Constantin Tuleasca, Thomas A. W. Bolton, Jean Régis, Elena Najdenovska, Tatiana Witjas, Nadine Girard, Francois Delaire, Marion Vincent, Mohamed Faouzi, Jean-Philippe Thiran, Meritxell Bach Cuadra, Marc Levivier and Dimitri Van De Ville

% most deactive voxels in each fMRI volume were considered for the clustering step, also discarding all remaining nonnull clusters with fewer than 6 neighboring elements. A CAP was defined as the average of all frames attributed to a cluster. For each CAP, we computed a dynamically informative subject-specific metric: the occurrence number (i.e., the number of times entering the assessed state). Thus, larger occurrence values reflect a more frequent expression of a given CAP during moments of seed activity. The retained fMRI volumes from posttherapeutic ET sessions

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Stereotactic radiosurgery for trigeminal neuralgia: a systematic review

International Stereotactic Radiosurgery Society practice guidelines

Constantin Tuleasca, Jean Régis, Arjun Sahgal, Antonio De Salles, Motohiro Hayashi, Lijun Ma, Roberto Martínez-Álvarez, Ian Paddick, Samuel Ryu, Ben J. Slotman and Marc Levivier

myelination (Schwann cells) transitions to central myelination (oligodendrocytes). The REZ is not fixed, and its location can vary from 0 to 3 mm from the nerve’s exit from the brainstem and is impossible to visualize on in vivo imaging. Some authors make the choice of an anterior versus a posterior target based on the idea that the nerve is more radiosensitive at the REZ than at the anterior part. Target Placement and Related Complications: Indirect Evidence From Dose-Volume Histograms Only 1 study documented dose-volume effects on the brainstem (dose-volume histogram [DVH

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Stereotactic body radiotherapy for de novo spinal metastases: systematic review

International Stereotactic Radiosurgery Society practice guidelines

Zain A. Husain, Arjun Sahgal, Antonio De Salles, Melissa Funaro, Janis Glover, Motohiro Hayashi, Masahiro Hiraoka, Marc Levivier, Lijun Ma, Roberto Martínez-Alvarez, J. Ian Paddick, Jean Régis, Ben J. Slotman and Samuel Ryu

fraction was delivered using a simultaneous integrated boost technique (24 Gy to gross tumor volume [GTV] in 1 patient and 18 Gy to clinical target volume [CTV] in 1 patient). Although none of the patients had undergone radiation previously, some patients had undergone previous surgical procedures; thus, inclusion was limited to 47 lesions in patients without previous surgery. The median follow-up duration for the entire group was 20 months. The median survival time for the entire group was 30 months, and survival times were similar in postoperative and de novo patients

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Stereotactic radiosurgery for tremor: systematic review

International Stereotactic Radiosurgery Society practice guidelines

Nuria E. Martínez-Moreno, Arjun Sahgal, Antonio De Salles, Motohiro Hayashi, Marc Levivier, Lijun Ma, Ian Paddick, Jean Régis, Sam Ryu, Ben J. Slotman and Roberto Martínez-Álvarez

to the volume of brain parenchyma receiving a given dose. Several indices are used to estimate that volume, e.g., the gradient index. 62 , 63 , 76 Matrix size also appears to have an influence. Larger matrices may result in longer procedure times, longer exposure times, and higher total doses. 65 Using a single smaller collimator helps minimize the dose to peripheral tissue. Lindquist et al. 42 reported 2 patients who were treated with doses of 180 and 200 Gy, using an 8- and 4-mm collimator, respectively. The lower dose yielded greater response but also more