Mean glandular dose to patients from stereotactic breast biopsy procedures.

The aim of this work is to study the radiation doses delivered to a group of patients that underwent a stereotactic breast biopsy (SBB) procedure. Mean glandular doses (MGD) were estimated from the air-kerma measured at the breast surface entrance multiplying by specific conversion coefficients (DgN) that were estimated using Monte Carlo simulations. DgN were calculated for the 0° and  ±15° projections used in SBB and for the particular beam quality.

Characterization and simulation of noise in PET images reconstructed with OSEM: Development of a method for the generation of synthetic images.

Introduction: The goals of the study are to characterize imaging properties in 2D PET images reconstructed with the iterative algorithm ordered-subset expectation maximization (OSEM) and to propose a new method for the generation of synthetic images.

Material And Methods: The noise is analyzed in terms of its magnitude, spatial correlation, and spectral distribution through standard deviation, autocorrelation function, and noise power spectrum (NPS), respectively. Their variations with position and activity level are also analyzed.

Diagnostic value of the stand-alone synthetic image in digital breast tomosynthesis examinations.

Objective: To demonstrate the non-inferiority of synthetic image (SI) mammography versus full-field digital mammography (FFDM) in breast tomosynthesis (DBT) examinations.

Methods: An observational, retrospective, single-centre, multireader blinded study was performed, using 2384 images to directly compare SI and FFDM based on Breast Imaging Reporting and Data System (BIRADS) categorisation and visibility of radiological findings. Readers had no access to digital breast tomosynthesis slices.

Automated Breast Density Computation in Digital Mammography and Digital Breast Tomosynthesis: Influence on Mean Glandular Dose and BIRADS Density Categorization.

Rationale And Objectives: The study aimed to compare the breast density estimates from two algorithms on full-field digital mammography (FFDM) and digital breast tomosynthesis (DBT) and to analyze the clinical implications.

Materials And Methods: We selected 561 FFDM and DBT examinations from patients without breast pathologies. Two versions of a commercial software (Quantra 2D and Quantra 3D) calculated the volumetric breast density automatically in FFDM and DBT, respectively.

Biplane interventional pediatric system with cone-beam CT: dose and image quality characterization for the default protocols.

The aim of this study was to assess image quality and radiation dose of a biplane angiographic system with cone-beam CT (CBCT) capability tuned for pediatric cardiac procedures. The results of this study can be used to explore dose reduction techniques. For pulsed fluoroscopy and cine modes, polymethyl methacrylate phantoms of various thicknesses and a Leeds TOR 18-FG test object were employed.

Evaluation of the technical performance of three different commercial digital breast tomosynthesis systems in the clinical environment.

The aim of this work was to research and evaluate the performance of three different digital breast tomosynthesis (DBT) systems in the clinical environment (Siemens Mammomat Inspiration, Hologic Selenia Dimensions, and Fujifilm Amulet Innovality). The characterization included the study of the detector, the automatic exposure control, and the resolution of DBT projections and reconstructed planes. The modulation transfer function (MTF) of the DBT projections was measured with a 1mm thick steel edge, showing a strong anisotropy (30-40% lower MTF0.

A study on image quality provided by a kilovoltage cone-beam computed tomography.

The image-guided radiotherapy technique (IGRT) makes use of imaging devices to verify the positions of the target volume and organs at risk during the treatment sessions. In this work we evaluate the image quality provided by an imaging system based on a kilovoltage cone-beam CT, and explore its ability to perform IGRT and adaptive radiotherapy. We analyze the accuracy of the image slice width, the spatial resolution using the MTF function, the image uniformity, the signal-to-noise ratio, the contrast-to-noise ratio, the low-contrast sensitivity, and the HU linearity with density.

SU-E-T-391: Modelling Peripheral Photon Dose in TomoTherapy Treatments.

Purpose: The delivery of the therapeutic radiation dose to the tumour in photon radiotherapy, also implies dose deposition in distant organs (peripheral dose) related to secondary cancers induction (Hall and Wuu, Int J Radiat Oncol Biol Phys 56:83-88, 2003). Therefore, peripheral dose estimation in MU-demanding techniques, such as Helical TomoTherapy (HT), becomes relevant. TLD measurements and Monte Carlo modelling were compared by D'Agostino (Strahlenther Onkol 187:693, 2011).

Insensitivity of leptogenesis with flavor effects to low energy leptonic CP violation.

If the baryon asymmetry of the Universe is produced by leptogenesis, CP violation is required in the lepton sector. In the seesaw extension of the standard model with three hierarchical right-handed neutrinos, we show that the baryon asymmetry is insensitive to the Pontecorvo-Maki-Nagakawa-Sakata phases: thermal leptogenesis can work for any value of the observable phases. This result was well known when there were no flavor effects in leptogenesis; we show that it remains true when flavor effects are included.