Cell surface proteins can play important roles in cancer pathogenesis. Comprehensive understanding of the surface protein expression patterns of tumor cells and, consequently, the pathogenesis of tumor cells, depends on molecular probes against these proteins. To be effectively used for tumor diagnosis, classification and therapy, such probes would be capable of specific binding to targeted tumor cells. Molecular aptamers, designer DNA/RNA probes, can address this challenge by recognizing proteins, peptides and other small molecules with high affinity and specificity. Through a process known as cell-SELEX, we used live acute myeloid leukemia (AML) cells to select a group of DNA aptamers that can recognize acute myeloid leukemia cells with dissociation constants (Kds) in the nanomolar range. Interestingly, one aptamer (KH1C12), compared with two control cell lines (K562 and NB4), showed significant selectivity to the target AML cell line (HL60) and could recognize the target cells within a complex mixture of normal bone marrow aspirates. The other two aptamers KK1B10 and KK1D04 recognize targets associated with monocytic differentiation. Our studies demonstrate that the selected aptamers can be used as a molecular tool for further understanding surface protein expression patterns on tumor cells and thus providing a foundation for effective molecular analysis of leukemia and its subcategories.
Purpose: Our intention was to perform some machine quality assurance (QA) tests that require the use of films with electronic portal imaging device (EPID). A software tool was designed for these tasks which include Light vs Radiation Field, Isocenter Star Shot, Winston‐Lutz and MLC Picket Fence images. Methods: For Light vs Radiation Field, BB dots were placed on the tabletop to indicate the light field and double‐exposure technique was used to enhance the display of BB dots. For Table Isocenter Star Shot, a square field was used, and a steel ruler was placed on the table to show one of the major axis on the images. For Winston‐Lutz test, we placed a small steel ball at isocenter and irradiate it with a square field from various gantry angles. For MLC Picket Fence test, we used a multi‐segment MLC field to deliver six rectangular fields adjacent to each other. In addition to the composite image, the EPID also saved the image from each segment. Our software analyzed the images of all segments. Results: The ability to save multiple images without entering the treatment room greatly shortened the overall time spent. The test results of Light vs Radiation Field, Isocenter Star Shot and Winston‐Lutz from the EPID are similar to the film, except the image quality is much better on EPID images. A significant advantage of EPID is that individual image of every segment can be saved and analyzed; where as one cannot determine accurately the position errors on a composite image of film. This analysis of EPID based images facilitates easy calibration of MLC leaves Conclusions: Compared to film method, the EPID images are of higher quality and better consistency. The software we developed provides us with fast, convenient, and accurate analysis for this application.
Purpose: Megavoltage Cone‐Beam CT (MVCBCT) is an essential image guided radiation therapy (IGRT) device to acquire patient's daily treatment CT for accurate localization of treatment targets. The objective of this research was to assess its image qualities. Method and Materials: The image quality of MVCBCT was assessed by four indicators: noise, contrast, spatial resolution, and CT intensity stability. A CT electron density phantom and a Siemens calibration phantom were used. The images were acquired under various MU settings. The Siemens Syngo image processing software was used to sample and analysis the data. Results: The noise factor was used and found that the more MU to acquire the images produced less noise. 6 MU is the cut‐off value for noise factor of less than 5%. For contrast of the outer ring of the CT phantom, the electron density range of <0.952 and >0.976 were visible on all MUs. For the inner ring, we only see <0.952 and >1.052 on MU <9 and >1.043 for MU > 15. For the CT intensity stability, if the CT number differences has to be <50 to qualify as “stable”, then 6 MU is the border line. For spatial resolution, MTF was used to evaluate Siemens phantom images. The lp/mm at MTF = 0.5 was 0.07, a little less than the criteria of 0.08 and for MTF = 0.1, we had 0.28, which is >criteria of 0.25. Conclusion: The images from MVCBCT device were assessed for quality indicators; we conclude that the MU of 6 or above would have satisfactory results. For the future application of dose calculation on the MVCBCT images, the CT intensity stability is important, and we found that for 6 MU and above would have stable CT numbers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.