Comparison of three F-labeled 2-nitroimidazoles for imaging hypoxia in breast cancer xenografts: [F]FBNA, [F]FAZA and [F]FMISO.

Background: Tumour hypoxia is associated with increased metastasis, invasion, poor therapy response and prognosis. Most PET radiotracers developed and used for clinical hypoxia imaging belong to the 2-nitroimidazole family. Recently we have developed novel 2-nitroimidazole-derived PET radiotracer [F]FBNA (N-(4-[F]fluoro-benzyl)-2-(2-nitro-1H-imidazol-1-yl)-acet-amide), an F-labeled analogue of antiparasitic drug benznidazole.

A comparative PET imaging study of Sc- and Ga-labeled bombesin antagonist BBN2 derivatives in breast and prostate cancer models.

Introduction: Radiolabeled peptides play a central role in nuclear medicine as radiotheranostics for targeted imaging and therapy of cancer. We have recently proposed the use of metabolically stabilized GRPR antagonist BBN2 for radiolabeling with F and Ga and subsequent PET imaging of GRPRs in prostate cancer. The present work studied the impact of Sc- and Ga-labeled DOTA complexes attached to GRPR antagonist BBN2 on the in vitro GRPR binding affinity, and their biodistribution and tumor uptake profiles in MCF7 breast and PC3 prostate cancer models.

Comparison of scandium-44 g with other PET radionuclides in pre-clinical PET phantom imaging.

Purpose: The decay characteristics of radionuclides in PET studies can impact image reconstruction. Sc has been the topic of recent research due to potential theranostic applications and is a promising radiometal for PET imaging. In this study, the reconstructed images from phantom measurements with scandium in a small-animal PET scanner are compared with F and two prominent radiometals: Cu and Ga METHODS: Three phantoms filled with F, C, Ga, and Sc were imaged in the Siemens Inveon PET scanner.

Activity cross-calibration of unsealed radionuclides utilizing a portable ion chamber.

Purpose: To present and evaluate an ion chamber-based method for the cross-calibration between sites of activity measurements of unsealed radionuclides. Notably, the method allows direct comparison of short lived (i.e.

Delivered dose uncertainty analysis at the tumor apex for ocular brachytherapy.

Purpose: To estimate the total dosimetric uncertainty at the tumor apex for ocular brachytherapy treatments delivered using 16 mm Collaborative Ocular Melanoma Study (COMS) and Super9 plaques loaded with (125)I seeds in order to determine the size of the apex margin that would be required to ensure adequate dosimetric coverage of the tumor.

Methods: The total dosimetric uncertainty was assessed for three reference tumor heights: 3, 5, and 10 mm, using the Guide to the expression of Uncertainty in Measurement/National Institute of Standards and Technology approach. Uncertainties pertaining to seed construction, source strength, plaque assembly, treatment planning calculations, tumor height measurement, plaque placement, and plaque tilt for a simple dome-shaped tumor were investigated and quantified to estimate the total dosimetric uncertainty at the tumor apex.

Detecting functional changes with [(18)F]FAZA in a renal cell carcinoma mouse model following sunitinib therapy.

Background: The multitargeting tyrosine kinase inhibitor (TKI) sunitinib is currently the first-line drug therapy for metastasizing renal cell carcinoma (RCC). TKIs have profound effects on tumor angiogenesis, leading to modifications of the tumor microenvironment. The goal of this study was to determine whether these treatment-induced changes can be detected with [(18)F]FAZA.

NEMA NU 4-2008 comparison of preclinical PET imaging systems.

Unlabelled: The National Electrical Manufacturers Association (NEMA) standard NU 4-2008 for performance measurements of small-animal tomographs was recently published. Before this standard, there were no standard testing procedures for preclinical PET systems, and manufacturers could not provide clear specifications similar to those available for clinical systems under NEMA NU 2-1994 and 2-2001. Consequently, performance evaluation papers used methods that were modified ad hoc from the clinical PET NEMA standard, thus making comparisons between systems difficult.

Biodistribution and uptake of 3'-deoxy-3'-fluorothymidine in ENT1-knockout mice and in an ENT1-knockdown tumor model.

Unlabelled: (18)F-3'-Deoxy-3'-fluorothymidine ((18)F-FLT) is a PET tracer that accumulates in proliferating tissues. The current study was undertaken to determine whether equilibrative nucleoside transporter 1 (ENT1) is important for (18)F-FLT uptake in normal tissues and tumors.

Methods: ENT1-knockout (ENT1(-/-)) mice were generated and compared with wild-type (ENT1(+/+)) mice using small-animal (18)F-FLT PET.

Investigation of a 3D system distortion correction method for MR images.

Interest has been growing in recent years in the development of radiation treatment planning (RTP) techniques based solely on Magnetic Resonance (MR) images. However, it is recognized that MR images suffer from scanner-related and object-induced distortions that may lead to an incorrect placement of anatomical structures. This subsequently may result in a reduced accuracy in delivering treatment dose fractions in RTP.