A system for quantitatively assessing certain performance parameters of gamma camera systems from reflective print and film transparency final images.

H V Piltingsrud; R G Hoops

doi:10.1118/1.595961

Home/Archive/PubMed

PubMed · 3951407

A system for quantitatively assessing certain performance parameters of gamma camera systems from reflective print and film transparency final images.

H V Piltingsrud·R G Hoops

View original source ↗Export metadata ↓

Abstract

Past efforts at routine evaluation of gamma camera systems performance, using final product images, primarily resulted in qualitative assessments. This paper describes a system for quantitatively determining certain performance parameters of gamma camera systems using paper-backed print and transparent film test images of the same type used for viewing by the nuclear medicine physician. By use of appropriate transmission and line source phantoms, the gamma camera system's spatial resolution, distortion, and flood field uniformity as a function of position in the image field, are determined using a semiautomated image scanning and data reduction system. This system consists of a high-resolution scanning microdensitometer/reflectometer, interfaced to a computer, along with necessary programs to locate bar and line grid intersection points in the image. Also included are algorithms for calculating the various image parameters desired. This system may provide an analytical method for quantitatively assessing certain performance parameters of gamma camera systems, using the final-product images from the cameras.

Explore related subjects

Densitometry Gamma Rays Humans Models, Theoretical Photography Tomography, X-Ray Computed Journal Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

H V Piltingsrud, R G Hoops. A system for quantitatively assessing certain performance parameters of gamma camera systems from reflective print and film transparency final images.. https://doi.org/10.1118/1.595961

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2006

Component volumes of unsaturated phosphatidylcholines in fluid bilayers: a densitometric study.

The specific volumes of six 1,2-diacylphosphatidylcholines with monounsaturated acyl chains (diCn:1PC, n=14-24 is the even number of acyl chain carbons) in fluid bilayers in multilamellar vesicles dispersed in H(2)O were determined by the vibrating tube densitometry as a function of temperature. From the data obtained with diCn:1PC (n=14-22) vesicles in combination with the densitometric data from Tristram-Nagle et al. [Tristram-Nagle, S., Petrache, H.I., Nagle, J.F., 1998. Structure and interactions of fully hydrated dioleoylphosphatidylcholine bilayers. Biophys. J. 75, 917-925.] and Koenig and Gawrisch [Koenig, B.W., Gawrisch, K., 2005. Specific volumes of unsaturated phosphatidylcholines in the liquid crystalline lamellar phase. Biochim. Biophys. Acta 1715, 65-70.], the component volumes of phosphatidylcholines in fully hydrated fluid bilayers at 30 degrees C were obtained. The volume of the acyl chain CH and CH(2) group is V(CH)=22.30 A(3) and V(CH2) =A(3), respectively. The volume of the headgroup including the glyceryl and acyl carbonyls, V(H), and the ratio of acyl chain methyl and methylene group volumes, r=V(CH3):V(CH2) are linearly interdependent: V(H)=a-br, where a=434.41 A(3) and b=-55.36 A(3) at 30 degrees C. From the temperature dependencies of component volumes, their isobaric thermal expansivities (alpha(X)=V(X)(-1)(partial differential V(X)/ partial differential T) where X=CH(2), CH, or H were calculated: alpha(CH2)=118.4x10(-5)K(-1), alpha(CH)=71.0x10(-5)K(-1), alpha(H)=7.9x10(-5)K(-1) (for r=2) and alpha(H)=9.6x10(-5)K(-1) (for r=1.9). The specific volume of diC24:1PC changes at the main gel-fluid phase transition temperature, t(m)=26.7 degrees C, by 0.0621 ml/g, its specific volume is 0.9561 and 1.02634 ml/g at 20 and 30 degrees C, respectively, and its isobaric thermal expansivity alpha=68.7x10(-5) and 109.2x10(-5)K(-1) below and above t(m), respectively. The component volumes and thermal expansivities obtained can be used for the interpretation of X-ray and neutron scattering and diffraction experiments and for the guiding and testing molecular dynamics simulations of phosphatidylcholine bilayers in the fluid state.

Densitometry↗

PubMed2006

[The diagnostics of osteoporosis in the evaluation of fracture risk].

Osteoporosis is a metabolic bone disease affecting a large portion of the population. In the osteoporotic process, organic and inorganic components on the bone are reduced, bone quality is deteriorated, strength of bone tissue is diminished, thus fracture risk is increasing as a consequence. Knowledge of the disease is essential for all physicians due to the frequency of this disorder. The aim of osteoporosis diagnostics is to discover the disease, to differentiate from other similar disorders, and to estimate fracture risk in order to introduce effective treatment. To carry out this task effectively, beside the proper evaluation of the patient's history, physical examination, osteodensitometry, X-ray and laboratory tests, some new factors revealed recently known to influence fracture risk should also be considered. The purpose of the present review is to summarize most recent data related to the diagnostics of osteoporosis from the view of the everyday practice.

Densitometry↗

PubMed2006

Portal verification of high-energy electron beams using their photon contamination by film-cassette systems.

BACKGROUND AND PURPOSE: Though electron beams are widely used in radiotherapy, their verification is not well established in clinical practice. The present study compares the suitability of several sensitive film-cassette systems for electron-portal verification by contaminating photons. MATERIAL AND METHODS: The characteristics of the optical density curves of film-cassette combinations were determined by exposing them to the bremsstrahlung contamination of a variety of electron beams. Using a Las-Vegas Phantom the spatial low-contrast resolution of the combinations was investigated. The absorbed dose rates due to the contaminant photons were measured for different geometric conditions. RESULTS: Suitable film-cassette combinations were found for portal verification of all usual electron energies. The best image quality was obtained using the EC film and the EC-L cassettes. For electron energies higher than 6 MeV some film-cassette combinations are suitable to verify abutted electron and photon portals using the same film sheet. CONCLUSION: The verification of electron portals and of abutted electron-photon portals can be performed by sensitive film-cassette systems with an image quality comparable to photon-beam verification.

Densitometry↗