Technical note: GAMMORA, a free, open-source, and validated GATE-based model for Monte-Carlo simulations of the Varian TrueBeam.

Purpose: Monte Carlo (MC) is the reference computation method for medical physics. In radiotherapy, MC computations are necessary for some issues (such as assessing figures of merit, double checks, and dose conversions). A tool based on GATE is proposed to easily create full MC simulations of the Varian TrueBeam STx.

A study of the interplay effect in radiation therapy using a Monte-Carlo model.

Purpose: In modulated radiotherapy, breathing motion can lead to Interplay (IE) and Blurring (BE) effects that can modify the delivered dose. The aim of this work is to present the implementation, the validation and the use of an open-source Monte-Carlo (MC) model that computes the delivered dose including these motion effects.

Methods: The MC model of the Varian TrueBeam was implemented using GATE.

Positioning accuracy of a single-isocenter multiple targets SRS treatment: A comparison between Varian TrueBeam CBCT and Brainlab ExacTrac.

Purpose: This study compared the positioning accuracy between cone-beam CT (CBCT) and ExacTrac (ETX) for a single-isocenter multiple target stereotactic radiosurgery (SRS) on two TrueBeam STx systems.

Methods: A single-isocenter treatment plan was simulated on an anthropomorphic head phantom with six spherical steel ball bearings (BBs). One of the BBs was chosen to be the isocenter.

Dosimetric performance of continuous EPID imaging in stereotactic treatment conditions.

Purpose: This study aims at investigating the dosimetric characteristics of a Varian aS1000 EPID, focusing on its continuous acquisition mode under the challenging conditions that can be met in stereotactic radiotherapy verification.

Methods: An aS1000 EPID installed on a Varian TrueBeamSTx was irradiated with 6 and 10 MV unflattened and flattened photon beams. In order to avoid detector saturation, the source-to-detector distance (SDD) was set to 150 or 180 cm depending on the dose rate.

A study of the interplay effect for VMAT SBRT using a four-axes motion phantom.

Purpose: To assess the accuracy of volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) when treating moving targets (such as lung or liver lesions), focusing on the impact of the interplay effect in the event of complex breathing motion and when a gating window is used.

Methods: A dedicated programmable motion platform was implemented. This platform can carry large quality assurance (QA) phantoms and achieve complex three-dimensional (3D) motion.

[Diagnosis, prognosis and treatment of sinonasal carcinomas (excluding melanomas, sarcomas and lymphomas)].

Sinonasal carcinomas account for 3% of ENT cancers. They are subdivided into squamous cell carcinomas (50%), adenocarcinomas [20%, mostly of intestinal type (ITAC)], and more rarely, adenoid cystic carcinomas, olfactory neuroblastomas (=esthesioneuroblastomas), neuroendocrine carcinomas or undifferentiated sinonasal carcinomas (SNUC). The 5-year survival rates are, in descending order, 72% for neuroblastomas, 63% for adenocarcinomas, 50-60% for large-cell neuroendocrine carcinomas, 53% for squamous cell carcinomas, 25-50% for adenoid cystic, 35% for small-cell neuroendocrine carcinomas and 35% for SNUC and newly discovered histologies.

Feasibility of Dose Escalation in Patients With Intracranial Pediatric Ependymoma.

Pediatric ependymoma carries a dismal prognosis, mainly owing to local relapse within RT fields. The current prospective European approach is to increase the radiation dose with a sequential hypofractionated stereotactic boost. In this study, we assessed the possibility of using a simultaneous integrated boost (SIB), comparing VMAT vs.

The GIRAFE phase II trial on MVCT-based "volumes of the day" and "dose of the day" addresses when and how to implement adaptive radiotherapy for locally advanced head and neck cancer.

During exclusive curative radiotherapy for head and neck tumors, the patient's organs at risk (OAR) and target volumes frequently change size and shape, leading to a risk of higher toxicity and lower control than expected on planned dosimetry. Adaptive radiotherapy is often necessary but 1) tools are needed to define the optimal time for replanning, and 2) the subsequent workflow is time-consuming. We designed a prospective study to evaluate 1) the validity of automatically deformed contours on the daily MVCT, in order to safely use the "dose-of the day" tool to check daily if replanning is necessary; 2) the automatically deformed contours on the replanning CT and the time gained in the replanning workflow.

[Observational study of outpatient unit duration of stay depending on the route of administration (intravenous vs subcutaneous) for a targeted therapy].

New routes of administration available for some targeted therapies, especially subcutaneous injections, have an impact not only on the patients' daycare experience, but also on the unit's organization. This observational study conducted on 48 voluntary patients at the Institut universitaire du cancer Toulouse-Oncopole shows that the mean duration of the outpatient unit stay is diminished by one hour when a subcutaneous injection is used instead of an intravenous route. This duration decrease is mainly caused by an 82% average reduction in treatment duration.

Spatio-spectral regularization to improve magnetic resonance spectroscopic imaging quantification.

Magnetic resonance spectroscopic imaging (MRSI) is a non-invasive technique able to provide the spatial distribution of relevant biochemical compounds commonly used as biomarkers of disease. Information provided by MRSI can be used as a valuable insight for the diagnosis, treatment and follow-up of several diseases such as cancer or neurological disorders. Obtaining accurate metabolite concentrations from in vivo MRSI signals is a crucial requirement for the clinical utility of this technique.

Virtual bolus for total body irradiation treated with helical tomotherapy.

Intensity-modulated radiation therapy (IMRT) for total body irradiation (TBI) is practiced in several centers using the TomoTherapy System. In this context the planning target volume (PTV) is the entire body including the skin. A safety margin in the air surrounding the body should be added to take into account setup errors.

Gamma index comparison of three VMAT QA systems and evaluation of their sensitivity to delivery errors.

Purpose: To compare detectors for dosimetric verification before VMAT treatments and evaluate their sensitivity to errors.

Methods And Materials: Measurements using three detectors (ArcCheck, 2d array 729 and EPID) were used to validate the dosimetric accuracy of the VMAT delivery. Firstly, performance of the three devices was studied.

Positron emission tomography/computed tomography imaging of residual skull base chordoma before radiotherapy using fluoromisonidazole and fluorodeoxyglucose: potential consequences for dose painting.

Purpose: To detect the presence of hypoxic tissue, which is known to increase the radioresistant phenotype, by its uptake of fluoromisonidazole (18F) (FMISO) using hybrid positron emission tomography/computed tomography (PET/CT) imaging, and to compare it with the glucose-avid tumor tissue imaged with fluorodeoxyglucose (18F) (FDG), in residual postsurgical skull base chordoma scheduled for radiotherapy.

Patients And Methods: Seven patients with incompletely resected skull base chordomas were planned for high-dose radiotherapy (dose ≥70 Gy). All 7 patients underwent FDG and FMISO PET/CT.

Combined proton and photon conformal radiotherapy for intracranial atypical and malignant meningioma.

Purpose: To evaluate retrospectively the efficacy of conformal fractionated radiotherapy combining proton and photon beams after primary surgery for treatment of atypical and malignant meningiomas.

Patients And Methods: Between September 1999 and October 2006, 24 patients (12 male, 12 female) with histopathologically proven meningioma (atypical 19, malignant 5) received postoperative combined radiotherapy with a 201-MeV proton beam at the Centre Protontherapie d'Orsay and a high-energy photon beam. Six patients underwent gross total resection and 18 a subtotal resection.

Proton therapy in pediatric skull base and cervical canal low-grade bone malignancies.

Purpose: To evaluate outcomes and tolerance of high-dose photon and proton therapy in the management of skull base and cervical canal primary bony malignancies in children.

Patients And Methods: Thirty children were treated postoperatively with high-dose photon-proton (29 patients) or protons-only (1 patient) radiotherapy. Twenty-six patients had chordomas (CH), 3 had low-grade chondrosarcomas (CS), and 1 had an aggressive chondroma (AC).

A treatment planning comparison of combined photon-proton beams versus proton beams-only for the treatment of skull base tumors.

Purpose: To compare treatment planning between combined photon-proton planning (CP) and proton planning (PP) for skull base tumors, so as to assess the potential limitations of CP for these tumors.

Methods And Materials: Plans for 10 patients were computed for both CP and PP. Prescribed dose was 67 cobalt Gray equivalent (CGE) for PP; 45 Gy (photons) and 22 CGE (protons) for CP.

Chordomas of the base of the skull and upper cervical spine. One hundred patients irradiated by a 3D conformal technique combining photon and proton beams.

To define the prognostic factors for local control and overall survival among 100 consecutive patients with chordoma of the base of skull or upper cervical spine treated by fractionated irradiation combining proton and photon beams. Between December 1993 and August 2002, 100 patients (median age: 53 years [8 - 85], M/F sex ratio: 3/2) were treated by a combination of high-energy photons and protons. The proton component was delivered at the Centre de Protonthérapie d'Orsay (CPO) by a 201 MeV beam.

Functional outcome of patients with benign meningioma treated by 3D conformal irradiation with a combination of photons and protons.

Purpose: To evaluate efficacy and tolerance of external fractionated combination of photon and proton radiation therapy (RT) for intracranial benign meningiomas.

Methods And Materials: Between 1994 and 2002, 51 patients with intracranial meningiomas of the base of the skull were treated with a combination of photon and proton RT. Median total dose was 60.

Radiotherapeutic factors in the management of cervical-basal chordomas and chondrosarcomas.

Objective: To define prognostic factors for local control and survival in 90 consecutive patients treated by fractionated photon and proton radiation for chordoma or chondrosarcoma of the cranial base and upper cervical spine.

Methods: Between December 1995 and December 2000, 90 patients (median age, 51.3 yr; range, 10-85 yr; male/female ratio, 3:2) were treated by a combination of high-energy photons and protons.

Practicability of protontherapy using compact laser systems.

Protontherapy is a well-established approach to treat cancer due to the favorable ballistic properties of proton beams. Nevertheless, this treatment is today only possible with large scale accelerator facilities which are very difficult to install at existing hospitals. In this article we report on a new approach for proton acceleration up to energies within the therapeutic window between 60 and 200 MeV by using modern, high intensity and compact laser systems.

Radiation therapy for chordoma and chondrosarcoma of the skull base and the cervical spine. Prognostic factors and patterns of failure.

Background: Prospective analysis of local tumor control, survival and treatment complications in 67 consecutive patients treated with fractionated photon and proton radiation for chordoma or chondrosarcoma of the base of the skull and the cervical spine.

Patients And Methods: Between December 1995 and January 2000, 67 patients with a median age of 52 years (range: 14-85 years), were treated at the Centre de Protonthérapie d'Orsay (CPO), France, using the 201-MeV proton beam, 49 for chordoma and 18 for chondrosarcoma. Irradiation combined high-energy photons and protons.

Proton beam therapy in the management of central nervous system tumors in childhood: the preliminary experience of the Centre de Protonthérapie d'Orsay.

Background: The purpose of the study was to evaluate clinical results and complications of a combination of proton and photon irradiation administered to 17 children with selected central nervous system (CNS) tumors.

Procedure: Between July 1994 and September 2000, 17 children, aged from 5 to 17 years (median: 12 years) with intracranial benign (6 cases) or malignant (11 cases) tumors, were treated with photons (median dose: 40 Gy; 24-54) and protons (median dose: 20 CGE; 9-31) at the Centre de Protonthérapie d'Orsay (CPO).

Results: Mean follow-up was 27 months (3-81).

Highly conformal therapy using proton component in the management of meningiomas. Preliminary experience of the Centre de Protonthérapie d'Orsay.

Aims: To evaluate the efficacy and the tolerance of an escalated dose of external conformal fractionated radiation therapy combining photons and protons in the treatment of intracranial meningiomas.

Patients And Methods: Between December 1995 and December 1999, 17 patients received a treatment by 201-MeV proton beam at the Centre de Protonthérapie d'Orsay (CPO) for a meningioma. Five patients presented a histologically atypical or malignant meningioma, twelve patients a benign one that was recurrent or rapidly progressive.

[Radiation therapy for chordomas and chondrosarcomas of the base of the skull and cervical spine].

Purpose: Prospective analysis of local tumour control, survival and treatment complications in 67 consecutive patients treated with fractionated photon and proton radiation for a chordoma or a chondrosarcoma of the base of the skull and of the cervical spine.

Patients And Methods: Between December 1995 and January 2000, 67 patients with a median age of 52.3 years (14-85), were treated using 201 MeV proton beam of the centre de protonthérapie d'Orsay (CPO), 49 for a chordoma and 18 for a chondrosarcoma.