A Highly Versatile X-ray and Electron Beam Diamond Dosimeter for Radiation Therapy and Protection.

Radiotherapy is now recognized as a pillar in the fight against cancer. Two different types are currently used in clinical practice: (1) external beam radiotherapy, using high-energy X-rays or electron beams, both in the MeV-range, and (2) intraoperative radiotherapy, using low-energy X-rays (up to 50 keV) and MeV-range electron beams. Versatile detectors able to measure the radiation dose independently from the radiation nature and energy are therefore extremely appealing to medical physicists.

A Diamond-Based Dose-per-Pulse X-ray Detector for Radiation Therapy.

One of the goals of modern dynamic radiotherapy treatments is to deliver high-dose values in the shortest irradiation time possible. In such a context, fast X-ray detectors and reliable front-end readout electronics for beam diagnostics are crucial to meet the necessary quality assurance requirements of care plans. This work describes a diamond-based detection system able to acquire and process the dose delivered by every single pulse sourced by a linear accelerator (LINAC) generating 6-MV X-ray beams.

Gamma Knife central lateral thalamotomy for the treatment of neuropathic pain.

Objective: The goal of this study was to assess the safety and efficacy of stereotactic central lateral thalamotomy with Gamma Knife radiosurgery in patients with neuropathic pain.

Methods: Clinical and radiosurgical data were prospectively collected and analyzed in patients with neuropathic pain who underwent Gamma Knife central lateral thalamotomy. The safety and efficacy of the lesioning procedure were evaluated by neurological examination and standardized scales for pain intensity and health-related quality of life.

MLC parameters from static fields to VMAT plans: an evaluation in a RT-dedicated MC environment (PRIMO).

Background: PRIMO is a graphical environment based on PENELOPE Monte Carlo (MC) simulation of radiotherapy beams able to compute dose distribution in patients, from plans with different techniques. The dosimetric characteristics of an HD-120 MLC (Varian), simulated using PRIMO, were here compared with measurements, and also with Acuros calculations (in the Eclipse treatment planning system, Varian).

Materials And Methods: A 10 MV FFF beam from a Varian EDGE linac equipped with the HD-120 MLC was used for this work.

Gamma Knife Radiosurgery for Short Unilateral Neuralgiform Headache Attacks with Conjunctival Injection and Tearing (SUNCT) Syndrome: Targeting the Trigeminal Nerve and the Sphenopalatine Ganglion. Case Report and Literature Review.

Background: Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) is a primary headache syndrome with an unclear pathogenesis, and only in very few cases, SUNCT is secondary to known lesions (secondary SUNCT). Several pharmacological as well as interventional and invasive treatments have been used to treat SUNT cases, with no definitive results. We describe a patient with idiopathic SUNCT syndrome, successfully treated with gamma knife radiosurgery and we report a review of the cases of the literature treated with radiosurgery.

Postmastectomy radiation therapy using VMAT technique for breast cancer patients with expander reconstruction.

Postmastectomy radiotherapy (PMRT) following immediate breast reconstruction is increasingly adopted in the management of breast cancer patients. We retrospectively evaluate the complication rates of PMRT using VMAT technique to immediate tissue expander-based reconstructions and the possible impact of tissue expander volume on radiotherapy planning. We reviewed the data of patients who underwent immediate expander breast reconstruction and received PMRT with VMAT (50 Gy in 25 fractions) on the reconstructed breast and axillary levels III-IV.

Computed tomography based radiomic signature as predictive of survival and local control after stereotactic body radiation therapy in pancreatic carcinoma.

Purpose: To appraise the ability of a radiomics signature to predict clinical outcome after stereotactic body radiation therapy (SBRT) for pancreas carcinoma.

Methods: A cohort of 100 patients was included in this retrospective, single institution analysis. Radiomics texture features were extracted from computed tomography (CT) images obtained for the clinical target volume.

Critical Appraisal of the Risk of Secondary Cancer Induction From Breast Radiation Therapy With Volumetric Modulated Arc Therapy Relative to 3D Conformal Therapy.

Purpose: To evaluate the excess absolute risk (EAR) comparing volumetric modulated arc therapy (VMAT) and 3-dimensional (3D) conformal radiation therapy (CRT) in breast cancer radiation therapy treatment.

Methods And Materials: Two VMAT arrangements (VMAT_tang and VMAT_full, i.e.

On the gEUD biological optimization objective for organs at risk in Photon Optimizer of Eclipse treatment planning system.

Inverse planning optimization using biologically based objectives is becoming part of the intensity modulated optimization process. The performances and efficacy of the biologically based gEUD (generalized Equivalent Uniform Dose) objective implemented in the Photon Optimizer (PO) of Varian Eclipse treatment planning system have been here analyzed. gEUD is associated with the parameter a that accounts for the seriality of a structure, being higher for more serial organs.

Is the PTW 60019 microDiamond a suitable candidate for small field reference dosimetry?

A systematic study of the PTW microDiamond (MD) output factors (OF) is reported, aimed at clarifying its response in small fields and investigating its suitability for small field reference dosimetry. Ten MDs were calibrated under Co irradiation. OF measurements were performed in 6 MV photon beams by a CyberKnife M6, a Varian DHX and an Elekta Synergy linacs.

Use of PTW-microDiamond for relative dosimetry of unflattened photon beams.

Purpose: The increasing interest in SBRT treatments encourages the use of flattening filter free (FFF) beams. Aim of this work was to evaluate the performance of the PTW60019 microDiamond detector under 6MV and 10MVFFF beams delivered with the EDGE accelerator (Varian Medical System, Palo Alto, USA). A flattened 6MV beam was also considered for comparison.

Evaluation of the dose calculation accuracy for small fields defined by jaw or MLC for AAA and Acuros XB algorithms.

Purpose: Small field measurements are challenging, due to the physical characteristics coming from the lack of charged particle equilibrium, the partial occlusion of the finite radiation source, and to the detector response. These characteristics can be modeled in the dose calculations in the treatment planning systems. Aim of the present work is to evaluate the MU calculation accuracy for small fields, defined by jaw or MLC, for anisotropic analytical algorithm (AAA) and Acuros XB algorithms, relative to output measurements on the beam central axis.

Can advanced new radiation therapy technologies improve outcome of high grade glioma (HGG) patients? analysis of 3D-conformal radiotherapy (3DCRT) versus volumetric-modulated arc therapy (VMAT) in patients treated with surgery, concomitant and adjuvant chemo-radiotherapy.

Background: To assess the impact of volumetric-modulated arc therapy (VMAT) compared with 3D-conformal radiotherapy (3DCRT) in patients with newly diagnosed high grade glioma in terms of toxicity, progression free survival (PFS) and overall survival (OS).

Methods: From March 2004 to October 2014, 341 patients underwent surgery followed by concomitant and adjuvant chemo-radiotherapy. From 2003 to 2010, 167 patients were treated using 3DCRT; starting from 2011, 174 patients underwent VMAT.

Accuracy evaluation of the optical surface monitoring system on EDGE linear accelerator in a phantom study.

Frameless stereotactic radiosurgery (SRS) requires dedicated systems to monitor the patient position during the treatment to avoid target underdosage due to involuntary shift. The optical surface monitoring system (OSMS) is here evaluated in a phantom-based study. The new EDGE linear accelerator from Varian (Varian, Palo Alto, CA) integrates, for cranial lesions, the common cone beam computed tomography (CBCT) and kV-MV portal images to the optical surface monitoring system (OSMS), a device able to detect real-time patient׳s face movements in all 6 couch axes (vertical, longitudinal, lateral, rotation along the vertical axis, pitch, and roll).

Characterization of a new unshielded diode for small field dosimetry under flattening filter free beams.

Purpose: To characterize the performance of a new unshielded silicon diode (Razor-IBA) for dose measurements in small flattening filter free beams.

Methods: The Razor has an active volume of 0.6 mm in diameter and 20 µm in length.

Flattening filter free beams from TrueBeam and Versa HD units: Evaluation of the parameters for quality assurance.

Purpose: Flattening filter free (FFF) beams generated by medical linear accelerators are today clinically used for stereotactical and non-stereotactical radiotherapy treatments. Such beams differ from the standard flattened beams (FF) in the high dose rate and the profile shape peaked on the beam central axis. Definition of new parameters as unflatness and slope for FFF beams has been proposed based on a renormalization factor for FFF profiles.

Are pitch and roll compensations required in all pathologies? A data analysis of 2945 fractions.

Objective: New linear accelerators can be equipped with a 6D robotic couch, providing two additional rotational motion axes: pitch and roll. These shifts in kilo voltage-cone beam CT (kV-CBCT) image-guided radiotherapy (IGRT) were evaluated over the first 6 months of usage of a 6D robotic couch-top, ranking the treatment sites for which the two compensations are larger for patient set-up.

Methods: The couch compensations of 2945 fractions for 376 consecutive patients treated on the PerfectPitch™ 6D couch (Varian(®) Medical Systems, Palo Alto, CA) were analysed.

Evaluation of a synthetic single-crystal diamond detector for relative dosimetry on the Leksell Gamma Knife Perfexion radiosurgery system.

Purpose: To evaluate the new commercial PTW-60019 synthetic single-crystal microDiamond detector (PTW, Freiburg, Germany) for relative dosimetry measurements on a clinical Leksell Gamma Knife Perfexion radiosurgery system.

Methods: Detector output ratios (DORs) for 4 and 8 mm beams were measured using a microDiamond (PTW-60019), a stereotactic unshielded diode [IBA stereotactic field detector (SFD)], a shielded diode (IBA photon field detector), and GafChromic EBT3 films. Both parallel and transversal acquisition directions were considered for PTW-60019 measurements.

Plan robustness in field junction region from arcs with different patient orientation in total marrow irradiation with VMAT.

Background: The cranial-caudal (CC) maximum LINAC couch shift is usually around 130-150 cm; therefore total marrow (and lymph-nodes) irradiation (TMI-TMLI) requires two different plans, one with patient head-first-supine ("body plan" - skull-thighs) and a second feet-first-supine ("legs plan" - feet-femurs head). A challenging planning is required to manage the region in which the radiation come from the two plans (that cannot be automatically optimized together). We studied a robust way to produce a plan sum in this field junction region without creating under/over dosage on PTV and hotspots out.

In-vivo dosimetry with Gafchromic films for multi-isocentric VMAT irradiation of total marrow lymph-nodes: a feasibility study.

Background: Total marrow (lymph-nodes) irradiation (TMI-TMLI) by volumetric modulated arc therapy (VMAT) was shown to be feasible by dosimetric feasibility studies. It was demonstrated that several partially overlapping arcs with different isocenters are required to achieve the desired coverage of the hematopoietic or lymphoid tissues targets and to spare the neighbouring healthy tissues. The effect of isocenter shifts was investigated with the treatment planning system but an in- vivo verification of the procedure was not carried out.

Nanodiamond-polymer composite fibers and coatings.

While nanocrystalline diamond is quickly becoming one of the most widely studied nanomaterials, achieving a large fraction of diamond nanoparticles in a polymer coating has been an unresolved problem. In this work, polymer nano- and microfibers containing high loadings of 5 nm diamond particles (up to 80 wt % in polyacrylonitrile and 40% in polyamide 11) have been demonstrated using electrospun nanofibers as a delivery vehicle. The electrospun nanofibers with a high load of nanodiamond in the polymers were fused into thin transparent films, which had high mechanical properties; an improvement of 4 times for the Young's modulus and 2 times for the hardness was observed already at 20% nanodiamond in polyamide 11.