It is generally acknowledged that calibration of the imaging system (be it a SPECT or a PET scanner) is one of the critical components associated with in vivo activity quantification in nuclear medicine. The system calibration is generally performed through the acquisition of a source with a known amount of radioactivity. The decay-corrected calibration factor is the "output" quantity in a meas...

When point calibration targets are used to calibrate a SAR image, the calibration accuracy is governed by two major factors. The first factor stems from the stringent requirement on the radar cross section (RCS) of the point calibration target. To reduce the effect of radar return from the background, the RCS of a point calibration target must be much larger than that of the background. Calibra...

BACKGROUND Breast density is a significant breast cancer risk factor measured from mammograms. The most appropriate method for measuring breast density for risk applications is still under investigation. Calibration standardizes mammograms to account for acquisition technique differences prior to making breast density measurements. We evaluated whether a calibration methodology developed for an...

Introduction In this work, a novel method using calculated calibration signal is introduced to improve high-pass GRAPPA (hp-GRAPPA) [1] when only limited auto-calibration signal (ACS) lines are acquired. Hp-GRAPPA suppresses the central calibration signal to reduce image support. When the number of ACS lines is limited, this suppression will result in insufficient calibration signal which cause...

Direct orthogonal signal correction(DOSC) and Savitzky-Golay filters (SGF) were applied as preprocessing methods on the original and first derivative absorbance data. Principle component regression (PCR), partial least squares (PLS) and iterative target transformation factor analysis (ITTFA), were used in spectrophotometric simultaneous determination of heavy divalent metal ions, l...

Normal erythrocytes were subject to swelling and some haemolysis when suspended in a NaCl-formaldehyde-Na(2)EDTA diluent of pH 4.9 for routine blood-cell counting in the Coulter counter. A phosphate-buffered saline of pH 7.4 was substituted and has proven satisfactory for total erythrocyte counts. Polyvinyltoluene latex was unsuitable for volume calibration of the counter, because of aggregatio...

We have evaluated the responsivity of seven different thermal detectors compared to an electrically calibrated photoacoustic reference detector at 119 μm (2.5 THz) and 394 μm (0.76 THz) laser wavelengths. Among the thermal detectors is an electrically calibrated thermopile having a vertically aligned carbon nanotube array as the absorber. We document the uncertainty contributions attributable t...

The current study shows a calibration method in gas chromatography (GC) with detection by mass spectrometry (MS) to quantify polychlorinated biphenyls (PCBs) present in transformer oils. The calibration was carried out with a secondary standard composed of a mixture of Aroclors (A1254:A1260), in one to one proportion and a reference standard (1,3,5-trichlorobenzene). This last one was used to e...

In this paper, measurement and calibration of a high-sensitivity microwave power sensor through an attenuator is performed using direct comparison transfer technique. To provide reliable results, a mathematical model previously derived using signal flow graphs together with non-touching loop rule analysis for the measurement estimate (i.e., calibration factor) and its uncertainty evaluation is ...