Accuracy and reproducibility of tumor positioning during prolonged and multi-modality animal imaging studies.

Dedicated small-animal imaging devices, e.g. positron emission tomography (PET), computed tomography (CT) and magnetic resonance imaging (MRI) scanners, are being increasingly used for translational molecular imaging studies.

Prediction of absorbed dose to normal organs in thyroid cancer patients treated with 131I by use of 124I PET and 3-dimensional internal dosimetry software.

Unlabelled: The objective of this work was to determine normal organ (131)I dosimetry in patients undergoing radioiodide therapy for thyroid cancer by use of serial scanning with (124)I PET.

Methods: A total of 26 patients who had papillary and follicular metastatic thyroid cancer and who were already enrolled in a Memorial Sloan-Kettering Cancer Center (131)I thyroid cancer protocol were selected for this study. Imaging before (131)I therapy consisted of multiple, whole-body (124)I PET studies over a period of 2-8 d, an (18)F-FDG PET scan and, for some, a diagnostic CT scan.

Patient-specific dosimetry for 131I thyroid cancer therapy using 124I PET and 3-dimensional-internal dosimetry (3D-ID) software.

Unlabelled: Compared with conventional, whole-organ, S-factor-based dosimetry, 3-dimensional (3D), patient-specific dosimetry better accounts for radionuclide distribution and anatomic patient variability. Its accuracy, however, is limited by the quality of the cumulated activity information that is provided as input. This input has typically been obtained from SPECT and planar imaging studies.

Correction for oral contrast artifacts in CT attenuation-corrected PET images obtained by combined PET/CT.

Unlabelled: Recent studies have shown increased artifacts in CT attenuation-corrected (CTAC) PET images acquired with oral contrast agents because of misclassification of contrast as bone. We have developed an algorithm, segmented contrast correction (SCC), to properly transform CT numbers in the contrast regions from CT energies (40-140 keV) to PET energy at 511 keV.

Methods: A bilinear transformation, equivalent to that supplied by the PET/CT scanner manufacturer, for the conversion of linear attenuation coefficients of normal tissues from CT to PET energies was optimized for BaSO(4) contrast agent.

Pharmacokinetics and Biodistribution of (86)Y-Trastuzumab for (90)Y dosimetry in an ovarian carcinoma model: correlative MicroPET and MRI.

Unlabelled: Preclinical biodistribution and pharmacokinetics of investigational radiopharmaceuticals are typically obtained by longitudinal animal studies. These have required the sacrifice of multiple animals at each time point. Advances in small-animal imaging have made it possible to evaluate the biodistribution of radiopharmaceuticals across time in individual animals, in vivo.

Murine S factors for liver, spleen, and kidney.

Unlabelled: Preclinical evaluation of new radiopharmaceuticals is performed in animal systems before testing is started in humans. These studies, often performed in murine or other rodent models, are important in understanding the relationship between absorbed dose and response, which can be translated to preclinical results for humans. In performing such calculations, either electrons are assumed to deposit all of their energy locally or idealized models of mouse anatomy are used to determine absorbed fractions.

Patient-specific, 3-dimensional dosimetry in non-Hodgkin's lymphoma patients treated with 131I-anti-B1 antibody: assessment of tumor dose-response.

Unlabelled: A comprehensive, SPECT-based, patient-specific 3-dimensional (3D) dosimetry analysis has been performed using 3D-ID, a previously developed software package. The role of the total-body tumor burden, individual lesion size, tumor absorbed dose, and the spatial distribution of the absorbed dose on response and on the time course of tumor shrinkage has been examined in patients with lymphoma treated by radioimmunotherapy.

Methods: Data from 15 patients participating in a phase II study of (131)I-labeled anti-B1 antibody (tositumomab) were used.