title: Validation of the circular harmonic transform (CHT) algorithm for quantitative SPECT.
abstract: The purpose of this study was to validate the use of the circular harmonic transform (CHT) algorithm for quantitative single-photon emission computed tomography (SPECT) with isotopes technetium-99m (99mTc) and indium-111 (111In) under clinically relevant conditions. Phantom studies were the principal tools used. Volumes of fillable organs within a tissue-equivalent anthropomorphic phantom were determined over a wide range (145-1960 ml) to within 6% by using a thresholding technique. Additionally, phantom studies with nonuniform activity distributions were made. These included a background of activity and hot as well as cold lesions. The hot lesion was computed to within 12% (111In) and 7.7% (99mTc), and contrast in the cold lesion was approximately 70% for both isotopes. The CHT algorithm incorporates the energy-distance relation (EDR) which minimizes the degrading effects of attenuation, scatter, collimator blur and poor statistics.
authors.affiliation: Johns Hopkins Oncology Center, Department of Radiation Oncology, Johns Hopkins Medical Institutions, Baltimore, Maryland 21231.
authors.forename: W G
authors.initials: WG
authors.lastname: Hawkins
authors.forename: N C
authors.initials: NC
authors.lastname: Yang
authors.forename: P K
authors.initials: PK
authors.lastname: Leichner
mesh_terms: D000465:Algorithms; D005583:Fourier Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007205:Indium Radioisotopes; D008961:Models, Structural; D013667:Technetium; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D007205:Indium Radioisotopes; D013667:Technetium