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Purpose: Prostate-specific membrane antigen (PSMA) is a cell surface protein with high expression in prostate carcinoma (PC) cells. Recently, procedures have been developed to label PSMA ligands with Ga, Tc and I. Our initial experience with Glu-NH-CO-NH-Lys-(Ahx)-[Ga(HBED-CC)](Ga-PSMA) suggests that this novel tracer can detect PC relapses and metastases with high contrast. The aim of this study was to investigate its biodistribution in normal tissues and tumour lesions. Methods: A total of 37 patients with PC and rising prostate-specific antigen (PSA) levels were subjected to Ga-PSMA positron emission tomography (PET)/CT. Quantitative assessment of tracer uptake was performed 1 and 3 h post-injection (p.i.) by analysis of mean and maximum standardized uptake values (SUV) of several organs and 65 tumour lesions. Subsequently, tumour to background ratios were calculated. Results: The PET/CT images showed intense tracer uptake in both kidneys and salivary glands. Moderate uptake was seen in lacrimal glands, liver, spleen and in small and large bowel. Quantitative assessment revealed excellent contrast between tumour lesions and most normal tissues. Of 37 patients, 31 (83.8 %) showed at least one lesion suspicious for cancer at a detection rate of 60 % at PSA <2.2 ng/ml and 100 % at PSA >2.2 ng/ml. Median tumour to background ratios were 18.8 (2.4-158.3) in early images and 28.3 (2.9-224.0) in late images. Conclusion: The biodistribution of the novel Ga-PSMA tracer and its ability to detect PC lesions was analysed in 37 patients. Within healthy organs, kidneys and salivary glands demonstrated the highest radiotracer uptake. Lesions suspicious for PC presented with excellent contrast as early as 1 h p.i. with high detection rates even at low PSA levels. [ABSTRACT FROM AUTHOR]

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A response from the authors of the article "PET imaging with a [68]Ga]gallium-labelled PSMA ligand for the diagnosis of prostate cancer: biodistribution in humans and first evaluation of tumour lesions" in the 2012 issue is presented.

A correction to the article "PET Imaging With a [68Ga]Gallium-Labelled PSMA Ligand for the Diagnosis of Prostate Cancer: Biodistribution in Humans and First Evaluation of Tumour Lesions" that was published online on March 2, 2013 is presented.

[Tl(OCH2Me)]4 (1) was reacted with excess HOR to prepare a series of [Tl(OR)]n, where OR = OCHMe2 (2, n = 4), OCMe3 (3, n = 4), OCH2CMe3 (4, n = 4), OC6H3(Me)2-2,6 (5, n = infinity), and OC6H3(CHMe2)2-2,6 (6, n = infinity). Single-crystal X-ray diffraction experiments revealed that in the solid state the alkoxide-ligated compound 4 adopts a cubane structure, whereas the aryloxide derivatives, 5 and 6, formed polymeric chains. Compounds 1-6 were also characterized by 203,205Tl solution and 205Tl solid-state NMR spectroscopy. In solution it was determined that 1-4 retained the [Tl-O]4 cube structure, whereas the polymeric species 5 and 6 appeared to be fluxional. Variations in the solution and solid-state structures for the [Tl(OR)]4 cubes and polymeric [Tl(OAr)]infinity are influenced by the steric hindrance of the ligand. The acidity of the parent alcohol influences the degree of covalency at the Tl metal center, which is reflected in the 203,205Tl chemical shifts for 1-6.