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Most NIR‐IIb fluorophores are nanoparticle‐based probes with long retention (≈1 month or longer) in the body. Here, we applied a novel cross‐linked coating to functionalize core/shell lead sulfide/cadmium sulfide quantum dots (PbS/CdS QDs) emitting at ≈1600 nm. The coating was comprised of an amphiphilic polymer followed by three crosslinked amphiphilic polymeric layers (P3 coating), imparting high biocompatibility and >90 % excretion of QDs within 2 weeks of intravenous administration. The P3‐QDs were conjugated to an engineered anti‐CD8 diabody (Cys‐diabody) for in vivo molecular imaging of CD8+ cytotoxic T lymphocytes (CTLs) in response to anti‐PD‐L1 therapy. Two‐plex molecular imaging in combination with down‐conversion Er nanoparticles (ErNPs) was performed for real‐time in vivo monitoring of PD‐L1 positive tumor cells and CTLs with cellular resolution by non‐invasive NIR‐IIb light sheet microscopy. Imaging of angiogenesis in the tumor microenvironment and of lymph nodes deep in the body with a signal‐to‐background ratio of up to ≈170 was also achieved using P3‐QDs. [ABSTRACT FROM AUTHOR]

The exquisite specificity of antibodies and antibody fragments renders them excellent agents for targeted delivery of radionuclides. Radiolabeled antibodies and fragments have been successfully used for molecular imaging and radioimmunotherapy (RIT) of cell surface targets in oncology and immunology. Protein engineering has been used for antibody humanization essential for clinical applications, as well as optimization of important characteristics including pharmacokinetics, biodistribution, and clearance. Although intact antibodies have high potential as imaging and therapeutic agents, challenges include long circulation time in blood, which leads to later imaging time points post‐injection and higher blood absorbed dose that may be disadvantageous for RIT. Using engineered fragments may address these challenges, as size reduction and removal of Fc function decreases serum half‐life. Radiolabeled fragments and pretargeting strategies can result in high contrast images within hours to days, and a reduction of RIT toxicity in normal tissues. Additionally, fragments can be engineered to direct hepatic or renal clearance, which may be chosen based on the application and disease setting. This review discusses aligning the physical properties of radionuclides (positron, gamma, beta, alpha, and Auger emitters) with antibodies and fragments and highlights recent advances of engineered antibodies and fragments in preclinical and clinical development for imaging and therapy. [ABSTRACT FROM AUTHOR]

Purpose: The most commonly used technology currently used for autoradiography is storage phosphor screens, which has many benefits such as a large field of view but lacks particle-counting detection of the time and energy of each detected radionuclide decay. A number of alternative designs, using either solid state or scintillator detectors, have been developed to address these issues. The aim of this study is to characterize the imaging performance of one such instrument, a double-sided silicon strip detector (DSSD) system for digital autoradiography. A novel aspect of this work is that the instrument, in contrast to previous prototype systems using the same detector type, provides the ability for user accessible imaging with higher throughput. Studies were performed to compare its spatial resolution to that of storage phosphor screens and test the implementation of multiradionuclide ex vivo imaging in a mouse preclinical animal study. Methods: Detector background counts were determined by measuring a nonradioactive sample slide for 52 h. Energy spectra and detection efficiency were measured for seven commonly used radionuclides under representative conditions for tissue imaging. System dead time was measured by imaging 18F samples of at least 5 kBq and studying the changes in count rate over time. A line source of 58Co was manufactured by irradiating a 10 μm nickel wire with fast neutrons in a research reactor. Samples of this wire were imaged in both the DSSD and storage phosphor screen systems and the full width at half maximum (FWHM) measured for the line profiles. Multiradionuclide imaging was employed in a two animal study to examine the intratumoral distribution of a 125I-labeled monoclonal antibody and a 131I-labeled engineered fragment (diabody) injected in the same mouse, both targeting carcinoembryonic antigen. Results: Detector background was 1.81 × 10-6 counts per second per 50 × 50 μm pixel. Energy spectra and detection efficiency were successfully measured for seven radionuclides. The system dead time was measured to be 59 μs, and FWHM for a 58Co line source was 154 ± 14 μm for the DSSD system and 343 ± 15 μm for the storage phosphor system. Separation of the contributions from 125I and 131I was performed on autoradiography images of tumor sections. Conclusions: This study has shown that a DSSD system can be beneficially applied for digital autoradiography with simultaneous multiradionuclide imaging capability. The system has a low background signal, ability to image both low and high activity samples, and a good energy resolution. [ABSTRACT FROM AUTHOR]

Objective To develop and implement Project LEAD (leadership, education, and advocacy development), a science course for breast cancer activists. Population Students were breast cancer activists and other consumers, mainly affiliated with advocacy organizations in the United States of America. Setting Project LEAD is offered by the National Breast Cancer Coalition; the course takes place over 5 days and is offered 4 times a year, in various cities in the United States of America. Results The Project LEAD curriculum has developed over 5 years to include lectures, problem-based study groups, case studies, interactive critical appraisal sessions, a seminar by an ‘expert’ scientist, role play, and homework components. A core faculty has been valuable for evaluating and revising the course and has proved necessary to provide consistent high quality teaching. Course evaluations indicated that students gained critical appraisal skills, enhanced their knowledge and developed confidence in selected areas of basic science and epidemiology. Conclusions Project LEAD comprises a unique curriculum for training breast cancer activists in science and critical appraisal. Course evaluations indicate that students gain confidence and skills from the course. [ABSTRACT FROM AUTHOR]