Extending the detectability index to quantitative imaging performance: applications in tomosynthesis and CT

2010 ◽  
Author(s):  
Samuel Richard ◽  
Baiyu Chen ◽  
Ehsan Samei
Keyword(s):  
Quantitative Imaging ◽  
Imaging Performance

Quantitative imaging performance of MARS spectral photon‐counting CT for radiotherapy

2020 ◽  
Vol 47 (8) ◽  
pp. 3423-3434 ◽  
Author(s):  
Mikaël Simard ◽  
Raj Kumar Panta ◽  
Stephen T. Bell ◽  
Anthony P.H. Butler ◽  
Hugo Bouchard
Keyword(s):  
Quantitative Imaging ◽  
Photon Counting ◽  
Imaging Performance

OC-0585: Quantitative imaging performance of MARS spectral photon-counting CT for radiotherapy

2020 ◽  
Vol 152 ◽  
pp. S328-S329
Author(s):  
M. Simard ◽  
R. Kumar Panta ◽  
H. Prebble ◽  
A.P.H. Butler ◽  
P.H. Butler ◽  
...  
Keyword(s):  
Quantitative Imaging ◽  
Photon Counting ◽  
Imaging Performance

scholarly journals A multicentre and multi-national evaluation of the accuracy of quantitative Lu-177 SPECT/CT imaging performed within the MRTDosimetry project

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Johannes Tran-Gia ◽  
Ana M. Denis-Bacelar ◽  
Kelley M. Ferreira ◽  
Andrew P. Robinson ◽  
Nicholas Calvert ◽  
...  
Keyword(s):  
Quantitative Imaging ◽  
Ct Imaging ◽  
Partial Volume Correction ◽  
Partial Volume ◽  
Volume Correction ◽  
Activity Recovery ◽  
Calibration Protocol ◽  
Imaging Performance ◽  
Comparison Exercise

Abstract Purpose Patient-specific dosimetry is required to ensure the safety of molecular radiotherapy and to predict response. Dosimetry involves several steps, the first of which is the determination of the activity of the radiopharmaceutical taken up by an organ/lesion over time. As uncertainties propagate along each of the subsequent steps (integration of the time–activity curve, absorbed dose calculation), establishing a reliable activity quantification is essential. The MRTDosimetry project was a European initiative to bring together expertise in metrology and nuclear medicine research, with one main goal of standardizing quantitative 177Lu SPECT/CT imaging based on a calibration protocol developed and tested in a multicentre inter-comparison. This study presents the setup and results of this comparison exercise. Methods The inter-comparison included nine SPECT/CT systems. Each site performed a set of three measurements with the same setup (system, acquisition and reconstruction): (1) Determination of an image calibration for conversion from counts to activity concentration (large cylinder phantom), (2) determination of recovery coefficients for partial volume correction (IEC NEMA PET body phantom with sphere inserts), (3) validation of the established quantitative imaging setup using a 3D printed two-organ phantom (ICRP110-based kidney and spleen). In contrast to previous efforts, traceability of the activity measurement was required for each participant, and all participants were asked to calculate uncertainties for their SPECT-based activities. Results Similar combinations of imaging system and reconstruction lead to similar image calibration factors. The activity ratio results of the anthropomorphic phantom validation demonstrate significant harmonization of quantitative imaging performance between the sites with all sites falling within one standard deviation of the mean values for all inserts. Activity recovery was underestimated for total kidney, spleen, and kidney cortex, while it was overestimated for the medulla. Conclusion This international comparison exercise demonstrates that harmonization of quantitative SPECT/CT is feasible when following very specific instructions of a dedicated calibration protocol, as developed within the MRTDosimetry project. While quantitative imaging performance demonstrates significant harmonization, an over- and underestimation of the activity recovery highlights the limitations of any partial volume correction in the presence of spill-in and spill-out between two adjacent volumes of interests.

Fluorescent potentiometric dyes for membrane-potential imaging

1994 ◽  
Vol 52 ◽  
pp. 166-167
Author(s):  
Leslie M. Loew
Keyword(s):  
Membrane Potential ◽  
Single Cells ◽  
Quantitative Imaging ◽  
Optical Recording ◽  
Biological Processes ◽  
Major Focus ◽  
The Past ◽  
Excitable Systems ◽  
Major Application ◽  
The Impact

A major application of potentiometric dyes has been the multisite optical recording of electrical activity in excitable systems. After being championed by L.B. Cohen and his colleagues for the past 20 years, the impact of this technology is rapidly being felt and is spreading to an increasing number of neuroscience laboratories. A second class of experiments involves using dyes to image membrane potential distributions in single cells by digital imaging microscopy - a major focus of this lab. These studies usually do not require the temporal resolution of multisite optical recording, being primarily focussed on slow cell biological processes, and therefore can achieve much higher spatial resolution. We have developed 2 methods for quantitative imaging of membrane potential. One method uses dual wavelength imaging of membrane-staining dyes and the other uses quantitative 3D imaging of a fluorescent lipophilic cation; the dyes used in each case were synthesized for this purpose in this laboratory.

The influence of confocal microscope design on imaging performance

1993 ◽  
Vol 51 ◽  
pp. 144-145
Author(s):  
C J R Sheppard
Keyword(s):  
Image Quality ◽  
Fluorescence Imaging ◽  
Confocal Microscope ◽  
Industrial Applications ◽  
Three Dimensions ◽  
Design Parameters ◽  
Weak Signals ◽  
Size And Shape ◽  
Imaging Performance ◽  
Fundamental Limitation

The confocal microscope is now widely used in both biomedical and industrial applications for imaging, in three dimensions, objects with appreciable depth. There are now a range of different microscopes on the market, which have adopted a variety of different designs. The aim of this paper is to explore the effects on imaging performance of design parameters including the method of scanning, the type of detector, and the size and shape of the confocal aperture.It is becoming apparent that there is no such thing as an ideal confocal microscope: all systems have limitations and the best compromise depends on what the microscope is used for and how it is used. The most important compromise at present is between image quality and speed of scanning, which is particularly apparent when imaging with very weak signals. If great speed is not of importance, then the fundamental limitation for fluorescence imaging is the detection of sufficient numbers of photons before the fluorochrome bleaches.

A new method for the observation of Type II magnetic contrast

1990 ◽  
Vol 48 (4) ◽  
pp. 764-765
Author(s):  
R.P. Ferrier ◽  
S. McVitie
Keyword(s):  
Domain Walls ◽  
Incident Beam ◽  
Objective Lens ◽  
Type Ii ◽  
Backscattering Coefficient ◽  
Magnetic Contrast ◽  
Standard Geometry ◽  
Backscattered Electron ◽  
Imaging Performance ◽  
Good Probe

Type II magnetic contrast was first observed by Philibert and Tixier and relies on the change in the effective backscattering coefficient due to interaction of the scattered electrons within the specimen and the local magnetic induction (for a review see Tsuno). Depending on the tilt of the specimen and the position of the backscattered electron detector(s), contrast due to the presence of either or both domains and domain walls can be obtained; in the case of the latter, the standard geometry is for the specimen to be normal to the incident beam and the detectors are positioned above it and close to the optic axis. This is the geometry adopted in our studies, which used a JEOL 2000FX with a special split objective lens polepiece; this permitted the specimen to be in magnetic field-free space, the separate lens gaps above and below allowing good probe forming capabilities combined with excellent Lorentz imaging performance. A schematic diagram is shown in Fig. 1.

New Feasible Concepts of Aberration Correction for Realizing High-Resolution Electron Microscopes

1990 ◽  
Vol 48 (1) ◽  
pp. 202-203
Author(s):  
H. Rose
Keyword(s):  
Spherical Aberration ◽  
Wave Length ◽  
Electron Wave ◽  
Optical Lens ◽  
Resolution Electron ◽  
Rotationally Symmetric ◽  
Electron Microscopes ◽  
The Cost ◽  
Imaging Performance ◽  
Acceleration Voltage

The imaging performance of the light optical lens systems has reached such a degree of perfection that nowadays numerical apertures of about 1 can be utilized. Compared to this state of development the objective lenses of electron microscopes are rather poor allowing at most usable apertures somewhat smaller than 10-2 . This severe shortcoming is due to the unavoidable axial chromatic and spherical aberration of rotationally symmetric electron lenses employed so far in all electron microscopes.The resolution of such electron microscopes can only be improved by increasing the accelerating voltage which shortens the electron wave length. Unfortunately, this procedure is rather ineffective because the achievable gain in resolution is only proportional to λ1/4 for a fixed magnetic field strength determined by the magnetic saturation of the pole pieces. Moreover, increasing the acceleration voltage results in deleterious knock-on processes and in extreme difficulties to stabilize the high voltage. Last not least the cost increase exponentially with voltage.

Do we need Quantitative Imaging?

2020 ◽  
Vol 59 (03) ◽  
pp. 225-226 ◽  
Author(s):  
Janet F. Eary ◽  
Winfried Brenner
Keyword(s):  
Quantitative Imaging
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