This study was carried out to obtain optimum operation conditions for X-ray machines. We investigated some factors affecting on quality assurance of conventional Siemen X-ray machine, inone of Mansoura Hospitals such as reproducibility of dose output, time and applied high voltage, Kilo-voltage accuracy, mA accuracy, time accuracy, and linearity. We measured these factors using Non-Invasive kil...

Introduction Accurate dose delivery is critical to the success of stereotactic radiosurgery. Unfortunately, verification of the accuracy of treatment delivery remains a challenging problem. Existing radiosurgery delivery paradigms are limited in their ability to verify the accurate delivery of radiation beams using data sampled from the beam after it has traversed the patient. The Zap-X Radiosu...

Recently a new iterative reconstruction algorithm named Iterative Reconstruction (SAFIRE) has been released by Siemens. This algorithm works in the raw data domain with noise reduction as main purpose, providing five different strengths. In this study, the effect of SAFIRE on image quality has been investigated using selected phantoms and a comparison with standard filtered back projection (FBP...

OBJECTIVE To investigate the dose-response relationship between breastfeeding duration and cognitive development in French preschool children. STUDY DESIGN In the French EDEN Mother-Child Cohort Study, we evaluated language ability with the Communicative Development Inventory (CDI) in 1387 2-year-old children and overall development with the Ages and Stages Questionnaire (ASQ) in 1199 3-year-...

The possible cancer risks caused by ionizing radiation doses of ~1 mSv or less are too small to be estimated directly from epidemiological data. The linear no-threshold (LNT) approach to estimating such risks involves using epidemiological data at higher (but still low) doses to establish an "anchor point", and then extrapolating the excess cancer risk linearly down from this point to the low d...

The high spatial resolution of radiochromic film makes it ideal for dosimetric measurements and dose distributions in regions of high dose gradient. Intensity-modulated radiation therapy, intravascular brachytherapy, and eye-plaque radiation therapy demand precise spatial dosimetric calculations. Such precision is not possible with conventional dosimeters, such as thermoluminescent dosimeters a...

The meaning and mathematical consequences of linearity (managing without a presumed ability to copy) are studied for a path-based model of processes which is also a model of affine-linear logic. This connection yields an affine-linear language for processes, automatically respecting open-map bisimulation, in which a range of process operations can be expressed. An operational semantics is provi...

background: since 1984 mri gel dosimetry has been introduced as a potential technique for 3d dosimetry. most of the studies have measured r1 (1/t1) or r2 (1/t2) properties of the gel depending on the gel type. we have studied image intensity change in the fricke gel by different mri protocols. materials and methods: gel dosimeters contain 0.4 mm ferrous sulphate, 1 mm nacl, 50 mm h2so4 and 1% b...

We describe two-step fluorescence microscopy, a new approach to non-linear imaging based on positive reversible photoswitchable fluorescent probes. The protein Padron approximates ideal two-step fluorescent behaviour: it equilibrates to an inactive state, converts to an active state under blue light, and blue light also excites this active state to fluoresce. Both activation and excitation are ...