Michela Lecchi

Current concepts on imaging in radiotherapy

New high-precision radiotherapy (RT) techniques, such as intensity-modulated radiation therapy (IMRT) or hadrontherapy, allow better dose distribution within the target and spare a larger portion of normal tissue than conventional RT. These techniques require accurate tumour volume delineation and intrinsic characterization, as well as verification of target localisation and monitoring of organ motion and response assessment during treatment. These tasks are strongly dependent on imaging technologies. Among these, computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography (US) and positron emission tomography (PET) have been applied in high-precision RT. For tumour volume delineation and characterization, PET has brought an additional dimension to the management of cancer patients by allowing the incorporation of crucial functional and molecular images in RT treatment planning, i.e. direct evaluation of tumour metabolism, cell proliferation, apoptosis, hypoxia and angiogenesis. The combination of PET and CT in a single imaging system (PET/CT) to obtain a fused anatomical and functional dataset is now emerging as a promising tool in radiotherapy departments for delineation of tumour volumes and optimization of treatment plans. Another exciting new area is image-guided radiotherapy (IGRT), which focuses on the potential benefit of advanced imaging and image registration to improve precision, daily target localization and monitoring during treatment, thus reducing morbidity and potentially allowing the safe delivery of higher doses. The variety of IGRT systems is rapidly expanding, including cone beam CT and US. This article examines the increasing role of imaging techniques in the entire process of high-precision radiotherapy.

Generation of the Acquisition-Specific NEC (AS-NEC) Curves to Optimize the Injected Dose in 3D

Aim of this work was the implementation and validation, for the Discovery-ST PET/CT (GE Medical Systems) system, of the acquisition-specific noise equivalent counts (AS-NEC) method to establish the amount of tracer to be injected in 3D

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F-FDG Whole Body PET Studies

F-FDG whole body (WB) PET studies to achieve the peak of the NEC (NEC-p) at the acquisition time. The AS-NEC method uses prompts, delayed events and detector dead-time of a single reference PET scan to calculate the full shape of the NEC curve. The method was implemented using a 3D decay series of the 70 cm NEMA 2001 (line source in a 20 cm diameter solid polyethylene cylinder) phantom and validated with the cylindrical NEMA 1994 (diameter, 20 cm; length, 20 cm) and NEMA 2001 IEC body phantoms. The NEC curves generated by the single frames of the phantom series, using the AS-NEC method, well correlated with the experimental NEC curves proving the validity of the method and the possible application to clinical studies. The AS-NEC model was then retrospectively applied on 40 3D

Comparative analysis of cadmium-zincum-telluride cameras dedicated to myocardial perfusion SPECT: A phantom study

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Correlation between 123I-FP-CIT brain SPECT and parkinsonism in dementia with Lewy bodies: caveat for clinical use.

F-FDG WB studies in a range of body mass index (BMI) between 16 and 30 (kg/m

Myocardial perfusion scintigraphy dosimetry: optimal use of SPECT and SPECT/CT technologies in stress-first imaging protocol

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Development of a bicistronic vector for multimodality imaging of estrogen receptor activity in a breast cancer model: preliminary application

) (6 under-weight (uw), 18 normal-weight (nw), 16 over-weight (ow)). For each acquisition frame of each patient study, the activity at the acquisition time, corresponding to the NEC-p was identified on the NEC curves. Furthermore, as the NEC curves show a region around the NEC-p with small variations (nearly a plateau), the values of radioactivity corresponding to a reduction of 1%, 3% and 5% with respect to NEC-p were also calculated to assess a possible reduction of the doses to be injected in clinical studies. The results show that the average activities at the acquisition time corresponding to the NEC-p were comparable for the three BMI classes: 336.7 MBq

In vivo neurochemistry with emission tomography and magnetic resonance spectroscopy: clinical applications

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Optimization of tracer injection for 3D /sup 18/F-FDG whole body (WB) PET studies using an acquisition-specific NEC (AS-NEC) cure generation

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