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Journal of Visualized Experiments : JoVE Aug 2018Cell migration is an important process that influences many aspects of health, such as wound healing and cancer, and it is, therefore, crucial for developing methods to...
Cell migration is an important process that influences many aspects of health, such as wound healing and cancer, and it is, therefore, crucial for developing methods to study the migration. The scratch assay has long been the most common in vitro method to test compounds with anti- and pro-migration properties because of its low cost and simple procedure. However, an often-reported problem of the assay is the accumulation of cells across the edge of the scratch. Furthermore, to obtain data from the assay, images of different exposures must be taken over a period of time at the exact same spot to compare the movements of the migration. Different analysis programs can be used to describe the scratch closure, but they are labor intensive, inaccurate, and forces cycles of temperature changes. In this study, we demonstrate an optimized method for testing the migration effect, e.g. with the naturally occurring proteins Human- and Bovine-Lactoferrin and their N-terminal peptide Lactoferricin on the epithelial cell line HaCaT. A crucial optimization is to wash and scratch in PBS, which eliminates the aforementioned accumulation of cells along the edge. This could be explained by the removal of cations, which have been shown to have an effect on keratinocyte cell-cell connection. To ensure true detection of migration, pre-treating with mitomycin C, a DNA synthesis inhibitor, was added to the protocol. Finally, we demonstrate the automated optical camera, which eliminates excessive temperature cycles, manual labor with scratch closure analysis, while improving on reproducibility and ensuring analysis of identical sections of the scratch over time.
Topics: Biological Assay; Cell Line; Cell Movement; Gamma Cameras; Humans; In Vitro Techniques; Reproducibility of Results
PubMed: 30148500
DOI: 10.3791/57691 -
Journal of Nuclear Medicine : Official... Sep 2019There has been an evolutionary leap in SPECT imaging with the advent of camera systems that use solid-state crystals and novel collimator designs configured specifically... (Review)
Review
There has been an evolutionary leap in SPECT imaging with the advent of camera systems that use solid-state crystals and novel collimator designs configured specifically for cardiac imaging. Solid-state SPECT camera systems have facilitated dramatic reductions in both imaging time and radiation dose while maintaining high diagnostic accuracy. These advances are related to simultaneous improvement in photon sensitivity due to the collimator and imaging geometry, as well as image resolution due to the improved energy resolution of the new crystals. Improved photon sensitivity has facilitated fast or low-dose myocardial perfusion imaging (MPI), and early dynamic imaging has emerged as a technique for assessing myocardial blood flow with SPECT. Lastly, general-purpose solid-state camera systems and hybrid SPECT/CT systems have also been developed that may have important clinical roles in cardiac imaging. This review summarizes state-of-the-art solid-state SPECT MPI technology and clinical applications, including emerging techniques for SPECT MPI flow estimation. We also discuss imaging protocols used with the new cameras, potential imaging pitfalls, and the latest data providing large-scale validation of the diagnostic and prognostic value of this new technology.
Topics: Computer Simulation; Coronary Artery Disease; Equipment Design; Gamma Cameras; Heart; Humans; Image Processing, Computer-Assisted; Motion; Multimodal Imaging; Myocardial Perfusion Imaging; Perfusion; Photons; Prognosis; Registries; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Ventricular Function, Left
PubMed: 31375568
DOI: 10.2967/jnumed.118.220657 -
Journal of Biomedical Physics &... Apr 2022Recent research on photon detection has led to the introduction of a silicone photomultiplier (SiPM) that operates at a low voltage and is insensitive to magnetic fields.
BACKGROUND
Recent research on photon detection has led to the introduction of a silicone photomultiplier (SiPM) that operates at a low voltage and is insensitive to magnetic fields.
OBJECTIVE
This work aims to model a scintillation camera with a SiPM sensor and to evaluate the camera reconstructed images from gamma ray projection data.
MATERIAL AND METHODS
The type of study in this research is experimental work and analytical. The scintillation camera, modelled from an SiPM sensor array SL4-30035, coupled with a scintillation material Caesium Iodide doped with Thallium (CsI(Tl)), is used in the experimental part. The performance of the camera was evaluated from reconstructed images by a back-projection technique of a radioactive source Caesium-137 (Cs-137).
RESULTS
The experiments conducted with a 1 µCi Cs-137 radioactive source have revealed that the bias voltage ( ) of the SiPM needs to be set to 27.8 V at an operating temperature between 43 °C to 44 °C. The radioactive source has to be placed within a 1 cm distance from the sensor to obtain the optimum projection data. Finally, the back-projection technique for image reconstruction with linear interpolation pre-processing has revealed that the Ram-Lak filter produces a better image contrast ratio compared to others.
CONCLUSION
This research has successfully modelled a scintillation camera with SiPM that was able to reconstruct images with an 86.4% contrast ratio from gamma ray projection data.
PubMed: 35433519
DOI: 10.31661/jbpe.v0i0.2009-1183 -
PloS One 2021We developed a compact and lightweight time-resolved mirrorless scintillation detector (TRMLSD) employing image processing techniques and a convolutional neural network...
PURPOSE
We developed a compact and lightweight time-resolved mirrorless scintillation detector (TRMLSD) employing image processing techniques and a convolutional neural network (CNN) for high-resolution two-dimensional (2D) dosimetry.
METHODS
The TRMLSD comprises a camera and an inorganic scintillator plate without a mirror. The camera was installed at a certain angle from the horizontal plane to collect scintillation from the scintillator plate. The geometric distortion due to the absence of a mirror and camera lens was corrected using a projective transform. Variations in brightness due to the distance between the image sensor and each point on the scintillator plate and the inhomogeneity of the material constituting the scintillator were corrected using a 20.0 × 20.0 cm2 radiation field. Hot pixels were removed using a frame-based noise-reduction technique. Finally, a CNN-based 2D dose distribution deconvolution model was applied to compensate for the dose error in the penumbra region and a lack of backscatter. The linearity, reproducibility, dose rate dependency, and dose profile were tested for a 6 MV X-ray beam to verify dosimeter characteristics. Gamma analysis was performed for two simple and 10 clinical intensity-modulated radiation therapy (IMRT) plans.
RESULTS
The dose linearity with brightness ranging from 0.0 cGy to 200.0 cGy was 0.9998 (R-squared value), and the root-mean-square error value was 1.010. For five consecutive measurements, the reproducibility was within 3% error, and the dose rate dependency was within 1%. The depth dose distribution and lateral dose profile coincided with the ionization chamber data with a 1% mean error. In 2D dosimetry for IMRT plans, the mean gamma passing rates with a 3%/3 mm gamma criterion for the two simple and ten clinical IMRT plans were 96.77% and 95.75%, respectively.
CONCLUSION
The verified accuracy and time-resolved characteristics of the dosimeter may be useful for the quality assurance of machines and patient-specific quality assurance for clinical step-and-shoot IMRT plans.
Topics: Gamma Cameras; Humans; Image Processing, Computer-Assisted; Neural Networks, Computer; Radiometry; Radiotherapy Dosage; Radiotherapy, Intensity-Modulated; Reproducibility of Results; Scintillation Counting; X-Rays
PubMed: 33577602
DOI: 10.1371/journal.pone.0246742 -
Physics in Medicine and Biology Sep 2011The development of radiation detectors capable of delivering spatial information about gamma-ray interactions was one of the key enabling technologies for nuclear... (Review)
Review
The development of radiation detectors capable of delivering spatial information about gamma-ray interactions was one of the key enabling technologies for nuclear medicine imaging and, eventually, single-photon emission computed tomography (SPECT). The continuous sodium iodide scintillator crystal coupled to an array of photomultiplier tubes, almost universally referred to as the Anger Camera after its inventor, has long been the dominant SPECT detector system. Nevertheless, many alternative materials and configurations have been investigated over the years. Technological advances as well as the emerging importance of specialized applications, such as cardiac and preclinical imaging, have spurred innovation such that alternatives to the Anger Camera are now part of commercial imaging systems. Increased computing power has made it practical to apply advanced signal processing and estimation schemes to make better use of the information contained in the detector signals. In this review we discuss the key performance properties of SPECT detectors and survey developments in both scintillator and semiconductor detectors and their readouts with an eye toward some of the practical issues at least in part responsible for the continuing prevalence of the Anger Camera in the clinic.
Topics: Equipment Design; Gamma Cameras; Humans; Nuclear Medicine; Radiation Monitoring; Radionuclide Imaging; Scintillation Counting; Semiconductors; Sensitivity and Specificity; Signal Processing, Computer-Assisted; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed
PubMed: 21828904
DOI: 10.1088/0031-9155/56/17/R01 -
Igaku Butsuri : Nihon Igaku Butsuri... 2022At present scintillation gamma camera plays key role in nuclear medicine as planner and tomographic single photon imaging modality. The basic technology of gamma camera... (Review)
Review
At present scintillation gamma camera plays key role in nuclear medicine as planner and tomographic single photon imaging modality. The basic technology of gamma camera made remarkable progress carried out by many researchers and engineers from around 1970 to 1980 and reached some matured stage as analog signal processing. Among them Dr. E. Tanaka made key contribution through the proposal of "Ideal arithmetics for position computer" (1969) and its implementation by the delay line time conversion (1970). These works triggered other unique position computing method applied to gamma camera products. This article reviews these technological progresses and outlines the next advances of gamma camera in the digital computer era.
Topics: Computers; Gamma Cameras; Nuclear Medicine; Radionuclide Imaging
PubMed: 35354731
DOI: 10.11323/jjmp.42.1_17 -
PET Clinics Jul 2018Recent advances in nuclear medicine instrumentation have led to the emergence of improved molecular imaging techniques to image breast cancer: dedicated gamma cameras... (Review)
Review
Recent advances in nuclear medicine instrumentation have led to the emergence of improved molecular imaging techniques to image breast cancer: dedicated gamma cameras using γ-emitting Tc-sestamibi and breast-specific PET cameras using F-fluorodeoxyglucose. This article focuses on the current role of such approaches in the clinical setting including diagnosis, assessing local extent of disease, monitoring response to therapy, and, for gamma camera imaging, possible supplemental screening in women with dense breasts. Barriers to clinical adoption and technologies and radiotracers under development are also discussed.
Topics: Breast; Breast Neoplasms; Female; Gamma Cameras; Humans; Positron-Emission Tomography; Radionuclide Imaging; Reproducibility of Results
PubMed: 30100076
DOI: 10.1016/j.cpet.2018.02.008 -
Expert Review of Anticancer Therapy Aug 2009Molecular breast imaging (MBI) is a new nuclear medicine technique that utilizes small semiconductor-based gamma-cameras in a mammographic configuration to provide... (Comparative Study)
Comparative Study Review
Molecular breast imaging (MBI) is a new nuclear medicine technique that utilizes small semiconductor-based gamma-cameras in a mammographic configuration to provide high-resolution functional images of the breast. Current studies with MBI have used Tc-99m sestamibi, which is an approved agent for breast imaging. The procedure is relatively simple to perform. Imaging can be performed within 5 min postinjection, with the breast lightly compressed between the two detectors. Images of each breast are acquired in the craniocaudal and mediolateral oblique projections facilitating comparison with mammography. Key studies have confirmed that MBI has a high sensitivity for the detection of small breast lesions. In patients with suspected breast cancer, MBI has an overall sensitivity of 90%, with a sensitivity of 82% for lesions less than 10 mm in size. Sensitivity was lowest for tumors less than 5 mm in size. Tumor detection does not appear to be dependent on tumor type, but rather on tumor size. Studies using MBI and breast-specific gamma-imaging have shown that these methods have comparable sensitivity to breast MRI. A large clinical trial compared MBI with screening mammography in over 1000 women with mammographically dense breast tissue and increased risk of breast cancer and showed that MBI detected two-to three-times more cancers than mammography. In addition, MBI appears to have slightly better specificity than mammography in this trial. MBI provides high-resolution functional images of the breast and its potential applications range from evaluation of the extent of disease to a role as an adjunct screening technique in certain high-risk populations. MBI is highly complementary to existing anatomical techniques, such as mammography, tomosynthesis and ultrasound.
Topics: Breast Neoplasms; Clinical Trials as Topic; Female; Gamma Cameras; Humans; Mammography; Radionuclide Imaging; Radiopharmaceuticals; Sensitivity and Specificity; Technetium Tc 99m Sestamibi
PubMed: 19671027
DOI: 10.1586/era.09.75 -
Seminars in Roentgenology Apr 2022Molecular breast imaging (MBI) is a nuclear medicine study performed with dedicated gamma camera systems optimized to image the uptake of Tc-99m sestamibi in the breast....
Molecular breast imaging (MBI) is a nuclear medicine study performed with dedicated gamma camera systems optimized to image the uptake of Tc-99m sestamibi in the breast. MBI provides a relatively low-cost and simple functional breast imaging method that can identify breast cancers obscured by dense fibroglandular tissue on mammography. Recent studies have also found that background levels of uptake in benign dense tissue may provide breast cancer risk information. This article discusses the latest updates in MBI technology, recent evidence supporting its clinical use, and work in progress that may aid in wider adoption of MBI.
Topics: Breast; Breast Neoplasms; Female; Gamma Cameras; Humans; Mammography; Molecular Imaging; Radiopharmaceuticals; Technetium Tc 99m Sestamibi
PubMed: 35523526
DOI: 10.1053/j.ro.2021.12.006