Dosimetric impact of different multileaf collimators on prostate intensity modulated treatment planning

AimThe main purpose of this study is to perform a dosimetric comparison on target volumes and organs at risks (OARs) between prostate intensity modulated treatment plans (IMRT) optimized with different multileaf collimators (MLCs).BackgroundThe use of MLCs with a small leaf width in the IMRT optimization may improve conformity around the tumor target whilst reducing the dose to normal tissues.Materials and methodsTwo linacs mounting MLCs with 5 and 10[[ce:hsp sp="0.25"/]]mm leaf-width, respectively, implemented in Pinnacle3 treatment planning system were used for this work. Nineteen patients with prostate carcinoma undergoing a radiotherapy treatment were enrolled. Treatment planning with different setup arrangements (7 and 5 beams) were performed for each patient and each machine. Dose volume histograms (DVHs) cut-off points were used in the treatment planning comparison.ResultsComparable planning target volume (PTV) coverage was obtained with 7- and 5-beam configuration (both with 5 and 10[[ce:hsp sp="0.25"/]]mm MLC leaf-width). The comparison of bladder and rectum DVH cut-off points for the 5-beam arrangement shows that 52.6% of the plans optimized with a larger leaf-width did not satisfy at least one of the OARs’ constraints. This percentage is reduced to 10.5% for the smaller leaf-width. If a 7-beam arrangement is used the value of 52.6% decreases to 21.1% while the value of 10.5% remains unchanged.ConclusionMLCs collimators with different widths and number of leaves lead to a comparable prostate treatment planning if a proper adjustment is made of the number of gantry angles

A multimodal approach to the treatment of bilateral choroidal metastases from thyroid carcinoma

A 58-year old man, affected by metastatic thyroid carcinoma, experienced a progressive bilateral visual impairment. Ophthalmic examination revealed the presence of a choroidal mass with an associated exudative retinal detachment in both eyes. Twelve years before, a diagnosis of metastatic thyroid carcinoma had been established and the patient had been subject to several therapeutic procedures

Aromatic Aminoacid Analogues Mimetic of BPA Transport - Use of O-(2-[18F]fluoroethyl)-L-tyrosine in Experimental Animal Model of F98 Glioma

A number of recent applications demonstrated the potential of radiolabeled aromatic aminoacids with Positron Emission Tomography (PET) for brain tumour imaging: the mechanism is similar to other metabolic substrate and it is based on their specific accumulation in neoplastic cells, probably linked to an increased expression of amino acid transporters, but not due to their incorporation in proteins. Although fluorine-18 (109.7 min half-life) is the most interesting radionuclide for the preparation of PET radiopharmaceuticals, the labeling of amino acids with fluoride-18 is often difficult, particularly in aromatic positions (the use of the molecular F2, is on the contrary chemically unsuitable and is limited to a few PET centres provided of special equipment and cyclotron targets). An alternative way of labelling aromatic systems with fluorine-18 involves the introduction of a fluoroalkyl group to an aromatic position, rather than by direct labelling with a fluorine atom. In this class a promising molecule for its applicable in neurooncology is the O-(2-[18F]fluoroethyl)-L-tyrosine (FET), one the first 18F-labeled amino acids. The tracer demontrated high in vivo stability, low uptake in inflammatory tissue and suitable uptake kinetics for clinical imaging. The main objective of this work is to demonstrate the feasibility of a novel approach for experimental BNCT, with a special focus to microimaging for the real assessment of the homogeneity and extent of accumulation of these class of aminoacid in tumour and surrounding healthy tissue. The goal of this study is then to use the FET to screen tumours lesions in experimental model with a small field of view PET, so called, micro PET. The micro PET-FET approach could lead to the assessment of the transport and the net influx and accumulation of FET molecule, as analogue to BPA. A correlation between BPA and FET pharmacokinetic, mainly linked to different affinities of transporters, could give numeric parameters useful for the assessment of boron loading in tumour and healthy tissues. The study present study was performed on implanted rats at the 3rd week after the tumour implantation (F98 glioma cell line). In the frame of this project was developed a simple and convenient remote controlled, one-pot synthesis module for FET, based on an automated Gilson module (mod. Aspec XL) with opportune hardware and software modifications performed in our laboratories. The radiosynthesis was performed via no-carrier-added 18F-fluorination of N-trityl-O-(2-tosyloxyethyl)-L-tyrosine-tert-butylester with subsequent deprotection under nonaqueous conditions in the presence of tetra-butyl ammonium hydrogen carbonate/carbonate. Deprotection of the intermediate FET derivative is performed in presence of trifluoroacetic acid in trichloromethane followed by solid-phase extraction. The FET containing HPLC eluent can be used for studies without purifications. The radiochemical purity is not less than 98% and the typical uncorrected radiochemical yield is higher than 40%; the total synthesis time is less than 90 min.JRC.F.3-Energy securit

THE BORON NEUTRON CAPTURE THERAPY FACILITIES REALIZED AT THE TAPIRO NUCLEAR REACTOR

COMUNICAZIONE A CONGRESSO AIRO, MILANO, 17 NOVEMBRE 200

Brain recurrences in patients with ovarian cancer: report of 12 cases and review of the literature

The aim of the investigation was to assess 12 cases of brain recurrences among ovarian cancer patients who had undergone surgery followed by platinum-based chemotherapy. Brain lesions were the first recurrence in 4 (33%) patients, the second recurrence in 7 (58%), and the fourth recurrence in one patient. The median time from ovarian cancer diagnosis to brain metastasis detection was 33.5 months (range, 13.5-86.5 months), brain metastases were multiple in 6 (50%) cases, and extra-cranial disease was present in 7 (58%) cases. Brain recurrence was symptomatic in 10 patients and the clinical presentation included impaired deambulation, extremity weakness, seizure, headache, nausea/vomiting and visual disturbance. Out of the 6 patients with single brain metastases, one underwent surgery, one had surgical excision followed by whole brain irradiation, 3 patients received stereotactic radiotherapy (followed by chemotherapy for coexistent extra-abdominal recurrence in one), and one had only symptomatic treatment. Out of the 6 patients with multiple brain metastases, four received whole brain irradiation (followed by chemotherapy for concomitant extra-cranial recurrence in one case), one patient had gamma-knife irradiation of three cerebral lesions (followed by chemotherapy for concurrent abdominal recurrence), and one patient had only symptomatic treatment. The median overall survival from diagnosis of brain metastasis was 8.3 months (range, 1-28 months), and it was not related to the number of brain metastases (multiple versus single), presence or absence of extra-cranial disease, or interval between ovarian cancer diagnosis and brain metastasis detection ( or =33.5 months). In conclusion, brain metastasis from ovarian cancer can represent a late manifestation of the disease, associated with a very poor prognosis

A multimodal approach to eye melanoma: patterns of care and related complications

We describe the results of multimodal treatment of uveal and conjunctival melanomas. A retrospective analysis was performed on 54 patients treated with a multimodal approach between 2003 and 2008 in a single institution. Main outcome measures were survival, enucleation rate, local tumor control, visual function preservation and complications associated with treatments. The median follow-up was 33.4 months. The 5-year overall survival was 95.3%, the local recurrence was 3.7% and the 5-year enucleation was 9.4%. Vision preservation was achieved in 84% of cases. Observed complications were cataract, retinal detachment, diplopia, glaucoma, retinopathy, optic neuropathy and scleral necrosis. A careful consideration of treatment of uveal melanoma in this study allowed us to obtain the survival rates and visual outcomes similar to previously published results, with a very small incidence of complications. the results must be interpreted in the light of recent findings on the genetic pattern of uveal melanoma

Micro-PET/CT approach with O-(2-[18F]fluorethyl)-L-tyrosine in experimental animal model of F98 Glioma for treatment planning

The present study focuses on micro-PET/CT application to be used for a specific PET Boron Distribution Treatment Planning System (BDTPS) which integrates in the same frame micro-CT derived anatomy and PET radiotracer distribution. Preliminary results have demonstrated that 18F-FET PET allows the identification of the extent of cerebral lesions in our animal model. FET uptake was assessed in glioma implanted and sham operated animals. The FET-PET approach could lead to the assessment of the transport, the net influx and the accumulation of FET as analogue of BPA in experimental animal model of glioma: coregistered micro-CT images allowed the accurate morphological localization of the radiotracer distribution and its perspective use for BDTPS simulations