Diagnostics in medicine plays a critical role in helping medical professionals deliver proper diagnostic decisions. Most samples in this trade are of the human origin and a great portion of methodologies practiced in biology labs is shared in clinical diagnostic laboratories as well. Most clinical tests are quantitative in nature and recent increase in interests in preventive medicine requires the determination of minimal concentration of target analyte: they exist in small quantities at the early stage of various diseases. Radiometry or the use of optical radiation is the most trusted and reliable means of converting biologic concentrations into quantitative physical quantities. Since optical energy is readily available in varying energies (or wavelengths), the appropriate combination of light and the sample absorption properties provides reliable information about the sample concentration through Beer-Lambert law to a decent precision. In this article, the commonly practiced techniques in clinical and biology labs are reviewed from the standpoint of radiometry.
Template matching method is presented to identify the peaks from the scanned signals of lateral flow immunoassay
strips. The template is composed of two pulses separated by the distance of the control and the target ligand line in the
assay, and is convolved with the scanned signal to deliver the maximum at the center of the two peaks. The peak regions
were identified with the predefined distances from the center. Glycosylated haemoglobin immunoassay strips and
fluorescent strip readers from Boditechmed Inc. were tested to estimate the lot and reader variations of the concentration
measurands. The results showed the robustness of the propose method.
Prostate-specific antigen (PSA) is an androgen-dependent glycoprotein protease (M.W. 33 kDa) and a member of kallikrein super-family of serine protease, and has chymotrypsin-like enzymatic activity. It is synthesized by the prostate epithelial cells and found in the prostate gland and seminal plasma as a major protein. It is widely used as a clinical marker for diagnosis, screening, monitoring and prognosis of prostate cancer. In normal male adults, the concentration of PSA in the blood is below 4 ng/ml and this value increases in patients with the prostate cancer or the benign prostatic hyperplasia (BPH) due to its leakage into the circulatory system. As such, systematic monitoring of the PSA level in the blood can provide critical information about the progress of the prostatic disease. We have fabricated a bread-board time resolved fluorescence system that could detect a concentration of Prostate Specific Antigen t-PSA) at clinically meaningful level in plasma as well as in whole blood sample. We chose Europium chelates as the fluorescence markers to attach to the PSA for its long decay lifetime and relative photostability. We have simplified the electronic circuits considerably by employing a MCS. With this setup, we have successfully proved that PSA concentration of 4pg/mL can be detected with acceptable reliability.
Prostate-specific antigen (PSA) is an androgen-dependent glycoprotein protease (M.W. 33 kDa) and a member of kallikrein super-family of serine protease, and has chymotrypsin-like enzymatic activity. It is synthesized by the prostate epithelial cells and found in the prostate gland and seminal plasma as a major protein. It is widely used as a clinical marker for diagnosis, screening, monitoring and prognosis of prostate cancer. In normal male adults, the concentration of PSA in the blood is below 4 ng/ml and this value increases in patients with the prostate cancer or the benign prostatic hyperplasia (BPH) due to its leakage into the circulatory system. As such, systematic monitoring of the PSA level in the blood can provide critical information about the progress of the prostatic disease. We have developed a compact integral system that can quantitatively measure the concentration of total PSA in human blood. This system utilizes the fluorescence emitted from the dye molecules attached to PSA molecules after appropriate immunoassay-based processing. Developed for the purpose of providing an affordable means of fast point-of-care testing of the prostate cancer, this system proved to be able to detect the presence of the PSA at the level of 0.18 ng/ml in less than 12 minutes, with the actual measurement taking less than 2 minutes. The design concept for this system is presented together with the result for a few representative samples.
A compact integral system was developed capable of quantitatively measuring analytes in biological fluids. This system uses the fluorescence as a reporter molecule to provide the information about the molecular density of the target molecule in the test sample. Developed for the purpose of providing an affordable means of fast point–of-care testing of marker molecules specifically arranged in the specimen, this system proved to be able to detect the presence of the marker agent at the level of 50 pg/ml in less than 15 minutes, with the actual measurement taking less than 1.5 minutes. The design concept for this unit is presented together with the result for a few representative samples.
We introduce an optical means of reconstructing the topology of rough objects under the microscope or at a relatively high magnification. First, 2D images were obtained under the conventional optical microscope or under the macroscopic imaging system, focused on differing height of the sample. The depth information was extracted by sensing the focus of each pixel of the conventional image slice. Each sample height associated with the best 'focus figure' for each pixel was marked and were later utilized to generate the 3D coordinate map.
A design concept of a mammography system is presented that is expected to reduce the background radiation without the penalty of the increased dosage or time. The monochromatic radiation from Mo target is Bragg reflected from a crystal mirror fabricated as per the Johansson geometry. Radiation then comes to a focus on the opposite side of the source point, and a pinhole located at this focal point will filter out the scattering from the bulk of the breast tissue. The focal spot size should be identical to the target spot size under an ideal circumstance. LiF crystal was assumed for the study, but any crystal with appropriate lattice constant and reflectivity can be adopted, depending on the difficulty of fabrication. Expected technical difficulties are presented and discussed.
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