The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Klaus Suhling - One of the best experts on this subject based on the ideXlab platform.
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Sub-??s time resolution in wide-field time-correlated single photon counting microscopy obtained from the photon event phosphor decay
New Journal of Physics, 2015Co-Authors: Liisa M. Hirvonen, Zden??k Petr????ek, Andrew Beeby, Klaus SuhlingAbstract:Fast frame rate complementary metal-oxide-semiconductor cameras in combination with photon counting image Intensifiers can be used for microsecond resolution wide-field fluorescence lifetime imaging with single photon sensitivity, but the time resolution is limited by the camera exposure time. We show here how the image Intensifier's P20 phosphor afterglow can be exploited for accurate timing of photon arrival well below the camera exposure time. By taking ratios of the intensity of the photon events in two subsequent frames, photon arrival times were determined with 300 ns precision with 18.5 mu s frame exposure time (54 kHz camera frame rate). Decays of ruthenium and iridium-containing compounds with around 1 mu s lifetimes were mapped with this technique, including in living HeLa cells, using excitation powers below 0.5 mu W. Details of the implementation to calculate the arrival time from the photon event intensity ratio are discussed, and we speculate that by using an image Intensifier with a faster phosphor decay to match a higher camera frame rate, photon arrival time measurements on the nanosecond time scale could be possible.
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Wide-field time-correlated single photon counting (TCSPC) microscopy with time resolution below the frame exposure time
Nuclear Instruments and Methods in Physics Research Section A: Accelerators Spectrometers Detectors and Associated Equipment, 2015Co-Authors: Liisa M. Hirvonen, Zdeněk Petrášek, Klaus SuhlingAbstract:Fast frame rate CMOS cameras in combination with photon counting Intensifiers can be used for fluorescence imaging with single photon sensitivity at kHz frame rates. We show here how the phosphor decay of the image Intensifier can be exploited for accurate timing of photon arrival well below the camera exposure time. This is achieved by taking ratios of the intensity of the photon events in two subsequent frames, and effectively allows wide-field TCSPC. This technique was used for measuring decays of ruthenium compound Ru(dpp) with lifetimes as low as 1 μs with 18.5 μs frame exposure time, including in living HeLa cells, using around 0.1 μW excitation power. We speculate that by using an image Intensifier with a faster phosphor decay to match a higher camera frame rate, photon arrival time measurements on the nanosecond time scale could well be possible.
Liisa M. Hirvonen - One of the best experts on this subject based on the ideXlab platform.
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Sub-??s time resolution in wide-field time-correlated single photon counting microscopy obtained from the photon event phosphor decay
New Journal of Physics, 2015Co-Authors: Liisa M. Hirvonen, Zden??k Petr????ek, Andrew Beeby, Klaus SuhlingAbstract:Fast frame rate complementary metal-oxide-semiconductor cameras in combination with photon counting image Intensifiers can be used for microsecond resolution wide-field fluorescence lifetime imaging with single photon sensitivity, but the time resolution is limited by the camera exposure time. We show here how the image Intensifier's P20 phosphor afterglow can be exploited for accurate timing of photon arrival well below the camera exposure time. By taking ratios of the intensity of the photon events in two subsequent frames, photon arrival times were determined with 300 ns precision with 18.5 mu s frame exposure time (54 kHz camera frame rate). Decays of ruthenium and iridium-containing compounds with around 1 mu s lifetimes were mapped with this technique, including in living HeLa cells, using excitation powers below 0.5 mu W. Details of the implementation to calculate the arrival time from the photon event intensity ratio are discussed, and we speculate that by using an image Intensifier with a faster phosphor decay to match a higher camera frame rate, photon arrival time measurements on the nanosecond time scale could be possible.
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Wide-field time-correlated single photon counting (TCSPC) microscopy with time resolution below the frame exposure time
Nuclear Instruments and Methods in Physics Research Section A: Accelerators Spectrometers Detectors and Associated Equipment, 2015Co-Authors: Liisa M. Hirvonen, Zdeněk Petrášek, Klaus SuhlingAbstract:Fast frame rate CMOS cameras in combination with photon counting Intensifiers can be used for fluorescence imaging with single photon sensitivity at kHz frame rates. We show here how the phosphor decay of the image Intensifier can be exploited for accurate timing of photon arrival well below the camera exposure time. This is achieved by taking ratios of the intensity of the photon events in two subsequent frames, and effectively allows wide-field TCSPC. This technique was used for measuring decays of ruthenium compound Ru(dpp) with lifetimes as low as 1 μs with 18.5 μs frame exposure time, including in living HeLa cells, using around 0.1 μW excitation power. We speculate that by using an image Intensifier with a faster phosphor decay to match a higher camera frame rate, photon arrival time measurements on the nanosecond time scale could well be possible.
Zden??k Petr????ek - One of the best experts on this subject based on the ideXlab platform.
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Sub-??s time resolution in wide-field time-correlated single photon counting microscopy obtained from the photon event phosphor decay
New Journal of Physics, 2015Co-Authors: Liisa M. Hirvonen, Zden??k Petr????ek, Andrew Beeby, Klaus SuhlingAbstract:Fast frame rate complementary metal-oxide-semiconductor cameras in combination with photon counting image Intensifiers can be used for microsecond resolution wide-field fluorescence lifetime imaging with single photon sensitivity, but the time resolution is limited by the camera exposure time. We show here how the image Intensifier's P20 phosphor afterglow can be exploited for accurate timing of photon arrival well below the camera exposure time. By taking ratios of the intensity of the photon events in two subsequent frames, photon arrival times were determined with 300 ns precision with 18.5 mu s frame exposure time (54 kHz camera frame rate). Decays of ruthenium and iridium-containing compounds with around 1 mu s lifetimes were mapped with this technique, including in living HeLa cells, using excitation powers below 0.5 mu W. Details of the implementation to calculate the arrival time from the photon event intensity ratio are discussed, and we speculate that by using an image Intensifier with a faster phosphor decay to match a higher camera frame rate, photon arrival time measurements on the nanosecond time scale could be possible.
Andrew Beeby - One of the best experts on this subject based on the ideXlab platform.
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Sub-??s time resolution in wide-field time-correlated single photon counting microscopy obtained from the photon event phosphor decay
New Journal of Physics, 2015Co-Authors: Liisa M. Hirvonen, Zden??k Petr????ek, Andrew Beeby, Klaus SuhlingAbstract:Fast frame rate complementary metal-oxide-semiconductor cameras in combination with photon counting image Intensifiers can be used for microsecond resolution wide-field fluorescence lifetime imaging with single photon sensitivity, but the time resolution is limited by the camera exposure time. We show here how the image Intensifier's P20 phosphor afterglow can be exploited for accurate timing of photon arrival well below the camera exposure time. By taking ratios of the intensity of the photon events in two subsequent frames, photon arrival times were determined with 300 ns precision with 18.5 mu s frame exposure time (54 kHz camera frame rate). Decays of ruthenium and iridium-containing compounds with around 1 mu s lifetimes were mapped with this technique, including in living HeLa cells, using excitation powers below 0.5 mu W. Details of the implementation to calculate the arrival time from the photon event intensity ratio are discussed, and we speculate that by using an image Intensifier with a faster phosphor decay to match a higher camera frame rate, photon arrival time measurements on the nanosecond time scale could be possible.
David J. Gladstone - One of the best experts on this subject based on the ideXlab platform.
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Camera selection for real-time in vivo radiation treatment verification systems using Cherenkov imaging
Medical Physics, 2015Co-Authors: Jacqueline M Andreozzi, Rongxiao Zhang, Adam K. Glaser, Lesley A Jarvis, Brian W Pogue, David J. GladstoneAbstract:PURPOSE: To identify achievable camera performance and hardware needs in a clinical Cherenkov imaging system for real-time, in vivo monitoring of the surface beam profile on patients, as novel visual information, documentation, and possible treatment verification for clinicians.\n\nMETHODS: Complementary metal-oxide-semiconductor (CMOS), charge-coupled device (CCD), intensified charge-coupled device (ICCD), and electron multiplying-intensified charge coupled device (EM-ICCD) cameras were investigated to determine Cherenkov imaging performance in a clinical radiotherapy setting, with one emphasis on the maximum supportable frame rate. Where possible, the image Intensifier was synchronized using a pulse signal from the Linac in order to image with room lighting conditions comparable to patient treatment scenarios. A solid water phantom irradiated with a 6 MV photon beam was imaged by the cameras to evaluate the maximum frame rate for adequate Cherenkov detection. Adequate detection was defined as an average electron count in the background-subtracted Cherenkov image region of interest in excess of 0.5% (327 counts) of the 16-bit maximum electron count value. Additionally, an ICCD and an EM-ICCD were each used clinically to image two patients undergoing whole-breast radiotherapy to compare clinical advantages and limitations of each system.\n\nRESULTS: Intensifier-coupled cameras were required for imaging Cherenkov emission on the phantom surface with ambient room lighting; standalone CMOS and CCD cameras were not viable. The EM-ICCD was able to collect images from a single Linac pulse delivering less than 0.05 cGy of dose at 30 frames/s (fps) and pixel resolution of 512 × 512, compared to an ICCD which was limited to 4.7 fps at 1024 × 1024 resolution. An Intensifier with higher quantum efficiency at the entrance photocathode in the red wavelengths [30% quantum efficiency (QE) vs previous 19%] promises at least 8.6 fps at a resolution of 1024 × 1024 and lower monetary cost than the EM-ICCD.\n\nCONCLUSIONS: The ICCD with an Intensifier better optimized for red wavelengths was found to provide the best potential for real-time display (at least 8.6 fps) of radiation dose on the skin during treatment at a resolution of 1024 × 1024.