Alberto Ciarmatori

Aim of the study was to evaluate feasibility and toxicities of exclusive radiosurgery using tomotherapy in patients with brain oligo-metastases. Between 2008 and 2013 68 patients underwent stereotactic radiosurgery (SRS). Mean patient age was 63 years. Brain was the only site involved in 32 patients, while 36 had extracranial disease. Pre-SRS MRI 56 patients had sovratentorial lesions, 10 subtentorial and 2 patients had both. Fifty-two patients had 1 brain lesion, 11 had 2, and 5 patients had three. All patients underwent SRS using Tomotherapy. The median delivered dose was 18 Gy. After a mean follow-up of 13 months, 14 patients were alive, while 54 patients had died. Two patients had complete response, 32 had partial response, 21 stable disease and 13 disease progression. Overall response rate was 80.9%. One- and two-year overall survival were 41,2% and 24,7%, while local control 61.5% and 37.7%. Toxicity was acceptable. SRS using tomotherapy has been proven feasible as non-invasive exclusive treatment for oligometastatic patients with good prognostic score.

Purpose To propose a magnetic resonance imaging (MRI) quality assurance procedure that can be used for multicenter comparison of different MR scanners for quantitative diffusion‐weighted imaging (DWI). Materials and Methods Twenty‐six centers (35 MR scanners with field strengths: 1T, 1.5T, and 3T) were enrolled in the study. Two different DWI acquisition series (b‐value ranges 0–1000 and 0–3000 s/mm², respectively) were performed for each MR scanner. All DWI acquisitions were performed by using a cylindrical doped water phantom. Mean apparent diffusion coefficient (ADC) values as well as ADC values along each of the three main orthogonal directions of the diffusion gradients (x, y, and z) were calculated. Short‐term repeatability of ADC measurement was evaluated for 26 MR scanners. Results A good agreement was found between the nominal and measured mean ADC over all the centers. More than 80% of mean ADC measurements were within 5% from the nominal value, and the highest deviation and overall standard deviation were 9.3% and 3.5%, respectively. Short‐term repeatability of ADC measurement was found <2.5% for all MR scanners. Conclusion A specific and widely accepted protocol for quality controls in DWI is still lacking. The DWI quality assurance protocol proposed in this study can be applied in order to assess the reliability of DWI‐derived indices before tackling single‐ as well as multicenter studies. J. Magn. Reson. Imaging 2015.

An anthropomorphic phantom was built using LEGO Mindstorms^® and programmed in LabVIEW^® for Adaptive Radiation Therapy (ART) purpose, to simulate the processes of breathing in the lung district during treatments. A thoracic cavity is prototyped by means of an 8 ribs apparatus and 2 artificial tumor masses, driven by intelligent brick LINUX^® OS CPU. An optical surface tracking system (VisionRT^®) and a QUASAR^™ phantom allow correlation between physiological, robotic motion and surrogated signal. Patient's breathing phases are acquired instantaneously by InfraRed/UltraSound sensors. Through 4DCT images, tumor center of mass are individuated and tracked during respiration, to link internal–external organs motion. To quantify the degree of divergences due to dynamics organs deformation, a 4D function was obtained and simulated by our phantom. Sinusoidal signals (6, 10, 12, 15 and 17 Breaths per Minute-BPM) were used for evaluating and commissioning, thereby obtained a correlation coefficient (0.90–0.94) between QUASAR and LEGO. Validated on ideal conditions, phantom was tested in clinical practice. Breaths and CT study of 12 patients were analyzed. Fitting of real breath sinograms returned a mean R value of 0.94 (0.83–0.98) with best model performance achieved in signals with respiratory frequency less than 20 BPM. By using LEGO it is possible to reproduce real patients conditions and simulate normal and even abnormal behavior during the course of therapy, allowing spatial motion estimation.

The radionuclide⁸⁹Zr (T_1/2=78.4ߙh) is particularly attractive for in vivo assessment of biochemical proesses characterized by biological half times in the order of several hours. In the present study we assessed the feasibility of⁸⁹Zr productionviathe⁸⁹Y(p,n)⁸⁹Zr reaction. Irradiation tests were performed using a 16.5ߙMeV GE-PETtrace cyclotron. High purity (>99.9%) yttrium metallic foils (0.15ߙmm) were irradiated in a solid target station developed in our Institution. The literature cross section data of all the nuclear reactions possible in the energy range of interest were carefully studied to optimize the irradiation parameters. The irradiated target was dissolved in 1ߙN HCl and the activity of the sample was measured in a CRC-15 PET dose calibrator, setting different values for the calibration factor. The sample activity was then measured usin g a calibrated HPGe gamma ray detector. A comparison of the activity measurements allowed the evaluation of the calibration factor for the Capintec CRC-15 PET; for a 3ߙml syringe geometry, it was found 739±60. Saturation yields of⁸⁹Zr were found to be 1150±110ߙMBq/μA for a single 0.15ߙmm thick disc irradiation (E_p=12.6→11.2ߙMeV) and 2400±220ߙMBq/μA for irradiation of two discs of total thickness 0.3ߙmm (E_p=12.6→9.5MeV). Total produced activities in the range of 200–400ߙMBq (according to target thickness) were repeatedly and safely obtained by 60ߙmin bombardments at 20ߙμA. Analysis of gamma ray spectra of all the samples showed a very high radionuclidic purity (>99.9995%).