Combined Imaging System Research Articles

An Automatic 3-D Ultrasound and Photoacoustic Combined Imaging System for Human Inflammatory Arthritis.

Aiming at a point-of-care device for rheumatology clinics, we developed an automatic 3-D imaging system combining the emerging photoacoustic (PA) imaging with conventional Doppler ultrasound (US) for detecting human inflammatory arthritis. This system is based on a commercial-grade GE HealthCare (GEHC, Chicago, IL, USA) Vivid E95 US machine and a Universal Robot UR3 robotic arm. This system automatically locates the patient's finger joints from a photograph taken by an overhead camera powered by an automatic hand joint identification method, followed by the robotic arm moving the imaging probe to the targeted joint to scan and obtain 3-D PA and Doppler US images. The GEHC US machine was modified to enable high-speed, high-resolution PA imaging while maintaining the features available on the system. The commercial-grade image quality and the high sensitivity in detecting inflammation in peripheral joints via PA technology hold great potential to significantly benefit clinical care of inflammatory arthritis in a novel way.

Initial clinical evaluation of a novel combined biometric, radio-frequency identification, and surface imaging system

PurposeTo evaluate and characterize the overall clinical functionality and workflow of the newly released Varian Identify system (version 2.3). MethodsThree technologies included in the Varian Identify system were evaluated: patient biometric authentication, treatment accessory device identification, and surface-guided radiation therapy (SGRT) function. Biometric authentication employs a palm vein reader. Treatment accessory device verification utilizes two technologies: device presence via Radio Frequency Identification (RFID) and position via optical markers. Surface-guidance was evaluated on both patient orthopedic setup at loading position and surface matching and tracking at treatment isocenter. A phantom evaluation of the consistency and accuracy for Identify SGRT function was performed, including a system consistency test, a translational shift and rotational accuracy test, a pitch and roll accuracy test, a continuous recording test, and an SGRT vs Cone-Beam CT (CBCT) agreement test. Results201 patient authentications were verified successfully with palm reader. All patient treatment devices were successfully verified for their presences and positions (indexable devices). The patient real-time orthopedic pose was successfully adjusted to match the reference surface captured at simulation. SGRT-reported shift consistency against couch readout was within (0.1 mm, 0.030). The shift accuracy was within (0.3 mm, 0.10). In continuous recording mode, the maximum variation was 0.2 ± 0.12 mm, 0.030 ± 0.020. The difference between Identify SGRT offset and CBCT was within (1 mm, 10). ConclusionsThis clinical evaluation confirms that Identify accurately functions for patient palm identification and patient treatment device presence and position verification. Overall SGRT consistency and accuracy was within (1 mm, 10), within the 2 mm criteria of AAPM TG302.

AFM is used to study the biophysics of hypertension-induced tachyarrhythmia.

Patients with long-lasting hypertension often suffer from atrial or ventricular arrhythmias. Evidence suggests that mechanical stimulation can change the refractory period and dispersion of the ventricular myocyte action potential through stretch-activated ion channels (SACs) and influence cellular calcium transients, thus increasing susceptibility to ventricular arrhythmias. However, the specific pathogenesis of hypertension-induced arrhythmias is unknown. In this study, through clinical data, we found that a short-term increase in blood pressure leads to a rise in tachyarrhythmias in patients with clinical hypertension. We investigated the mechanism of this phenomenon using a combined imaging system(AC) of atomic force microscopy (AFM) and laser scanning confocal microscopy. After mechanical distraction to stimulate ventricular myocytes isolated from Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR), we synchronously monitored cardiomyocyte stiffness and intracellular calcium changes. This method can reasonably simulate cardiomyocytes' mechanics and ion changes when blood pressure rises rapidly. Our results indicated that the stiffness value of cardiomyocytes in SHR was significantly more extensive than that of normal controls, and cardiomyocytes were more sensitive to mechanical stress; In addition, intracellular calcium increased rapidly and briefly in rats with spontaneous hypertension. After intervention with streptomycin, a SAC blocker, ventricular myocytes are significantly less sensitive to mechanical stimuli. Thus, SAC is involved in developing and maintaining ventricular arrhythmias induced by hypertension. The increased stiffness of ventricular myocytes caused by hypertension leads to hypersensitivity of cellular calcium flow to mechanical stimuli is one of the mechanisms that cause arrhythmias. The AC system is a new research method to study the mechanical properties of cardiomyocytes. This study provides new techniques and ideas for developing new anti-arrhythmic drugs. HIGHLIGHT: The mechanism of hypertension-induced tachyarrhythmia is not precise. Through this study, it is found that the biophysical properties of myocardial abnormalities, the myocardium is excessively sensitive to mechanical stimulation, and the calcium flow appears to transient explosive changes, leading to tachyarrhythmia.

Characterizing a photoacoustic and fluorescence imaging platform for preclinical murine longitudinal studies.

To effectively study preclinical animal models, medical imaging technology must be developed with a high enough resolution and sensitivity to perform anatomical, functional, and molecular assessments. Photoacoustic (PA) tomography provides high resolution and specificity, and fluorescence (FL) molecular tomography provides high sensitivity; the combination of these imaging modes will enable a wide range of research applications to be studied in small animals. We introduce and characterize a dual-modality PA and FL imaging platform using in vivo and phantom experiments. The imaging platform's detection limits were characterized through phantom studies that determined the PA spatial resolution, PA sensitivity, optical spatial resolution, and FL sensitivity. The system characterization yielded a PA spatial resolution of in the transverse plane and in the longitudinal axis, a PA sensitivity detection limit not less than that of a sample with absorption coefficient , an optical spatial resolution of in the vertical axis and in the horizontal axis, and a FL sensitivity detection limit not concentration of IR-800. The scanned animals displayed in three-dimensional renders showed high-resolution anatomical detail of organs. The combined PA and FL imaging system has been characterized and has demonstrated its ability to image mice in vivo, proving its suitability for biomedical imaging research applications.

A.I. Pipeline for Accurate Retinal Layer Segmentation Using OCT 3D Images

An image data set from a multi-spectral animal imaging system was used to address two issues: (a) registering the oscillation in optical coherence tomography (OCT) images due to mouse eye movement and (b) suppressing the shadow region under the thick vessels/structures. Several classical and A.I.-based algorithms, separately and in combination, were tested for each task to determine their compatibility with data from the combined animal imaging system. The hybridization of A.I. with optical flow followed by homography transformation was shown to be effective (correlation value > 0.7) for registration. Resnet50 backbone was shown to be more effective than the famous U-net model for shadow region detection with a loss value of 0.9. A simple-to-implement analytical equation was shown to be effective for brightness manipulation with a 1% increment in mean pixel values and a 77% decrease in the number of zeros. The proposed equation allows the formulation of a constraint optimization problem using a controlling factor α for the minimization of the number of zeros, the standard deviation of the pixel values, and maximizing the mean pixel value. For layer segmentation, the standard U-net model was used. The A.I.-Pipeline consists of CNN, optical flow, RCNN, a pixel manipulation model, and U-net models in sequence. The thickness estimation process had a 6% error compared with manually annotated standard data.

Mango (Mangifera indica cv. Sein Ta Lone) ripeness level prediction using color and textural features of combined reflectance-fluorescence images

Sein Ta lone mango of different maturity level images has been obtained using reflectance and fluorescence imaging systems. It has been found that fluorescence images show interesting patterns in correlation with the accumulation of bluish fluorescence compounds in the lenticel spots on the mango surface. Color and textural features of both reflectance and fluorescence images have been evaluated to develop a ripeness prediction model. The results show that combining color features of reflectance image and textural features could increase the R2 of the Partial Least Square Regression (PLSR) model up to 0.97 for Brix prediction and 0.99 for pH prediction with Root Mean Square Error (RMSE) of 0.5 for both. These results show the potential of the combined reflectance-fluorescence imaging system for mango ripeness assessment.

Modern approaches of high-voltage transmission lines monitoring

Transmission lines require timely inspection and monitoring to prevent emergency situations during operation. System emergency situations as blackout are very undesirable, so they need their previous detection and prevention. Accordingly, this can be avoided by detailed monitoring the functioning of all elements of the power system. The directions of remote control for researching the operational state of electric power facilities through the use of special equipment, in particular aerial vehicles, have gained sufficient development. Possibilities of practical means of remote monitoring of power transmission lines are also considered. Due to their relatively inexpensive use and ease of operation, distant controlled aerial vehicles are an effective approach for surveying high-voltage power lines. A number of advantages of using distant controlled aerial vehicles are the extended functionality of monitoring quality provided by modern equipment. Functional analysis of modern on-board equipment indicates the possibility of detecting research objects on a real-time scale, due to the use of telemetry, satellite and combined television and thermal imaging systems, with the possibility of detailed observe. The most perspective is the use of combined heat-television systems, which allow improving the technical characteristics of the surveillance system significantly. This method provides monitoring of heat losses, detection of overheated elements of transmission lines and assessment of the performance of elements. Such technology ensures more safer and timely detection of malfunctions, threats to operation and carrying out work on their elimination. In addition, the fields of application of distant controlled aerial vehicles as surveys for the design of energy systems are increasing.

Combined Scattering, Interferometric, and Fluorescence Oblique Illumination for Live Cell Nanoscale Imaging

To determine the molecular and/or mechanical basis of cell migration using live cell imaging tools, it is necessary to correlate multiple 3D spatiotemporal events simultaneously. Fluorescence nanoscopy and label-free nanoscale imaging can complement each other by providing both molecular specificity and structural dynamics of sub-cellular structures. A combined imaging system would permit obtaining quantitative 3D spatial temporal details of individual cellular components. In this paper, we empirically determined optimal azimuthal scanning angles of rotating beams to achieve simultaneous and label-free nanoscale and fluorescence imaging. Label-free nanoscale imaging here refers to interferometric, bright-field (BF) and dark-field (DF) rotating coherence scattering (ROCS) microscopy, while fluorescence refers to high-inclined laminated oblique (HiLO) and total internal reflection fluorescence (TIRF) imaging. The combined capabilities of interferometric, scattering, and fluorescence imaging enable (1) the identification of molecular targets (substrate or organelle), (2) quantification of 3D cell morphodynamics, and (3) tracking of intracellular organelles in 3D. This combined imaging tool was then used to characterize migrating platelets and endothelial cells, both critical to the process of infection and wound healing. The combined imaging results of more than ∼1000 platelets suggest that serum albumin (bovine) is necessary for platelets to migrate and scavenge fibrin/fibrinogen. Furthermore, we identified new asynchronous membrane fluctuations between the leading and rear edges of a migrating platelet. We further demonstrated that interferometric imaging permits the quantification of mitochondrial dynamics on human lung microvascular endothelial cells. Our data suggests that axial displacement of mitochondria is minimal when it is closer to the nucleus or the leading edge of a cell membrane. Taken together, this combined nanoscopy platform helps to quantify multiple spatial temporal events of a migrating cell that will undoubtedly open ways to new quantitative correlative nanoscale live cell imaging.

Comparison of instantaneous knee kinematics during walking and running

BackgroundAccurate measurements of in-vivo knee joint kinematics are essential to elucidate healthy knee motion and the changes that accompany injury and repair. Although numerous experimental measurements have been reported, the accurate non-invasive analysis of in-vivo knee kinematics remains a challenge in biomechanics. Research questionThe study objective was to investigate in-vivo knee kinematics before, at, and after contact during walking and running using a combined high-speed dual fluoroscopic imaging system (DFIS) and magnetic resonance (MR) imaging technique. MethodsThree-dimensional (3D) knee models of ten participants were created using MR images. Knee kinematics during walking and running were determined using high-speed DFIS. The 3D knee models were then related to fluoroscopic images to obtain in-vivo six-degrees-of-freedom knee kinematics. ResultsBefore contact knee flexion, external femoral rotation, and proximal-distal distance were 11.9°, 3.4°, and 1.0 mm greater during running compared to walking, respectively. Similar differences were observed at initial contact (9.9°, 7.9°, and 0.9 mm, respectively) and after contact (6.4°, 2.2°, and 0.8 mm, respectively). Posterior femoral translation at initial contact was also increased during running compared to walking. SignificanceThis study demonstrated accurate instantaneous in-vivo knee kinematic characteristics that may further the understanding of the intrinsic biomechanics of the knee during gait.

Validation of a combined ultrasound and bioluminescence imaging system with magnetic resonance imaging in orthotopic pancreatic murine tumors

Preclinical mouse solid tumor models are widely used to evaluate efficacy of novel cancer therapeutics. Recent reports have highlighted the need for utilizing orthotopic implantation to represent clinical disease more accurately, however the deep tissue location of these tumors makes longitudinal assessment challenging without the use of imaging techniques. The purpose of this study was to evaluate the performance of a new multi-modality high-throughput in vivo imaging system that combines bioluminescence imaging (BLI) with robotic, hands-free ultrasound (US) for evaluating orthotopic mouse models. Long utilized in cancer research as independent modalities, we hypothesized that the combination of BLI and US would offer complementary advantages of detection sensitivity and quantification accuracy, while mitigating individual technological weaknesses. Bioluminescent pancreatic tumor cells were injected into the pancreas tail of C57BL/6 mice and imaged weekly with the combination system and magnetic resonance imaging (MRI) to serve as a gold standard. BLI photon flux was quantified to assess tumor activity and distribution, and US and MRI datasets were manually segmented for gross tumor volume. Robotic US and MRI demonstrated a strong agreement (R2 = 0.94) for tumor volume measurement. BLI showed a weak overall agreement with MRI (R2 = 0.21), however, it offered the greatest sensitivity to detecting the presence of tumors. We conclude that combining BLI with robotic US offers an efficient screening tool for orthotopic tumor models.

Investigation into wind effects on fire spread on inclined wooden rods by multi-spectrum and schlieren imaging

A combined imaging system that can monitor the visible flame, invisible hot flow, flame temperature and surface temperature was developed to investigate the combustion of wooden rods inclined at 30° under forced air flow. A micro wind tunnel is designed to generate the forced air flow that is at an angle with the fire rod. It is found that a low-speed air flow can enhance the combustion of the burning lifetime and charring rate, while a high wind speed can decrease the intensity of combustion. There were three aspects that were found to influence the burning and spreading of the fire: 1. The effect of flame temperature; 2. The temperature change of the wooden surface; 3. The effect of the flow field around the burning rods, particularly for the flow field underneath the rod surface. The statistics and visualisation have enhanced the understanding of the mechanisms of wood combustion in a forced air flow. The developed imaging system is beneficial for monitoring the combustion process because it can monitor the flame temperature, wood surface temperature and visualise the invisible hot combustion products simultaneously.

Development of a PET/EPRI combined imaging system for assessing tumor hypoxia

Precise quantitative delineation of tumor hypoxia is essential in radiation therapy treatment planningto improve the treatment efficacy by targeting hypoxic sub-volumes.We developed a combined imaging system of positron emission tomography (PET) and electron para-magnetic resonance imaging (EPRI) of molecular oxygento investigate the accuracy of PET imaging in assessing tumor hypoxia.The PET/EPRI combined imaging system aims to use EPRI to precisely measure the oxygen partial pressure in tissues.This will evaluate the validity of PET hypoxic tumor imaging by (near) simultaneously acquired EPRI as ground truth. The combined imaging system was constructed by integrating a small animal PET scanner (inner ring diameter 62 mm and axial field of view 25.6 mm)and an EPRI subsystem (field strength 25 mT and resonant frequency 700 MHz).The compatibility between the PET and EPRI subsystems were tested with both phantom and animal imaging.Hypoxic imaging on a tumor mouse model using 18F-fluoromisonidazole radio-tracerwas conducted with the developed PET/EPRI system.We report the development and initial imaging results obtained from the PET/EPRI combined imaging system.

Determination of relative position of antenna system and RGB-D sensor in combined microwave imaging system

Microwave imaging technique allows obtaining images of hidden objects in structures and media using microwaves. This technique has various applications such as: nondestructive testing, medical imaging, concealed weapon detection, through-the-wall imaging, etc. Obtaining radar images in these applications is based on processing phase and amplitude of the reflected signal recorded over an aperture (a microwave hologram). Recently, systems began to appear in which the radar part is supplemented by an RGB-D sensor, which allows to obtain new capabilities. For example, there is the a microwave screening system architecture in which inverse synthetic aperture is formed by the natural motion of the subject in the vicinity of a stationary linear antenna array. The microwave system is complemented with an synchronous RGB-D video sensor which captures the trajectory of the moving subject in 3D and allows coherent processing of the radar signal. Another system detects objects buried under irregular surface and uses RGB-D sensor for capturing the surface relief for suppressing reflection of the sounding signal from the surface. Calibration between a radar and an RGB-D sensor is an essential process for microwave and optical data fusion. This article presents a novel approach for calibration, using a planar calibration target which is made of radiotransparent material (such a foam plastic sheet) with square marker and six small metal balls embedded in target surface and representing point objects. The proposed method exploits 3D-3D correspondences between coordinates of point objects in two coordinate systems associated to the sensor and to the radar. One points set is extracted from optical data, using marked corners of the target as a base points. Second points set is obtained from microwave data as local maxima of 3D volume of data reconstructed from one-frequency microwave hologram. Computer modeling were performed using Autodesk 3ds Max software by which models of all components of the system were built and the optical image from the sensor was modeled. Test experiments were carried out using a measurement system composed of the following components: a compact vector network analyzer (VNA), two mechanical scanners with stepper motors, one transmitting and one receiving horn antennas, mounted on the VNA, an RGB-D sensor, a microcontroller board, and a computer. The high accuracy of the method is confirmed both by computer modeling and physical experiment. The accuracy of determination of relative position between the radar and the sensor is about one fifth of the signal wavelength used.

Relative Orientation Method for Airborne Pushbroom Combined Imaging System

Relative Orientation Method for Airborne Pushbroom Combined Imaging System

Shortwave infrared hyperspectral imaging system coupled with multivariable method for TVB-N measurement in pork

Monitoring and maintaining the freshness of meat is important to ensuring a supply of meat that is safe for consumption. The objective of this study is to present a shortwave infrared (SWIR) hyperspectral imaging system in combination with partial least-squares regression (PLSR) model and feature selection methods that can be used for the prediction of the total volatile basic nitrogen (TVB-N) content in fresh pork. The SWIR hyperspectral reflectance images were acquired for pork samples removed from refrigerated storage after 1, 4, 8, 11, 15, and 21 days. The hyperspectral SWIR images and actual TVB-N contents were used for constructing the PLSR model. PLSR models were optimized by using feature selection strategies such as random frog (RF) and variable importance in projection (VIP) score. The predictions from the optimal RF-PLSR model value with maximum normalization preprocessing exhibited correlation coefficient values for Rc2 and Rp2 of 0.94 and 0.90, respectively. Moreover, this research showed that visualization of TVB-N levels applied to the optimal model based on selected wavebands provide an intuitive way to interpret the spatial information of the sample. This study revealed that the multivariate models developed here for rapid and nondestructive evaluation of pork freshness can be feasible for use in online inspection systems as an effective substitute for traditional methods to evaluate pork freshness.

Autofluorescence Imaging of 3D Tumor-Macrophage Microscale Cultures Resolves Spatial and Temporal Dynamics of Macrophage Metabolism.

Macrophages within the tumor microenvironment (TME) exhibit a spectrum of protumor and antitumor functions, yet it is unclear how the TME regulates this macrophage heterogeneity. Standard methods to measure macrophage heterogeneity require destructive processing, limiting spatiotemporal studies of function within the live, intact 3D TME. Here, we demonstrate two-photon autofluorescence imaging of NAD(P)H and FAD to nondestructively resolve spatiotemporal metabolic heterogeneity of individual macrophages within 3D microscale TME models. Fluorescence lifetimes and intensities of NAD(P)H and FAD were acquired at 24, 48, and 72 hours poststimulation for mouse macrophages (RAW264.7) stimulated with IFNγ or IL4 plus IL13 in 2D culture, confirming that autofluorescence measurements capture known metabolic phenotypes. To quantify metabolic dynamics of macrophages within the TME, mouse macrophages or human monocytes (RAW264.7 or THP-1) were cultured alone or with breast cancer cells (mouse polyoma-middle T virus or primary human IDC) in 3D microfluidic platforms. Human monocytes and mouse macrophages in tumor cocultures exhibited significantly different FAD mean lifetimes and greater migration than monocultures at 24, 48, and 72 hours postseeding. In cocultures with primary human cancer cells, actively migrating monocyte-derived macrophages had greater redox ratios [NAD(P)H/FAD intensity] compared with passively migrating monocytes at 24 and 48 hours postseeding, reflecting metabolic heterogeneity in this subpopulation of monocytes. Genetic analyses further confirmed this metabolic heterogeneity. These results establish label-free autofluorescence imaging to quantify dynamic metabolism, polarization, and migration of macrophages at single-cell resolution within 3D microscale models. This combined culture and imaging system provides unique insights into spatiotemporal tumor-immune cross-talk within the 3D TME. SIGNIFICANCE: Label-free metabolic imaging and microscale culture technologies enable monitoring of single-cell macrophage metabolism, migration, and function in the 3D tumor microenvironment.

A Dual-Frequency Coupled Resonator Transducer.

New ultrasound-mediated drug delivery systems, such as acoustic cluster therapy or combined imaging and therapy systems, require transducers that can operate beyond the bandwidth limitation (~100%) of conventional piezoceramic transducers. In this article, a dual-frequency coupled resonator transducer (CRT) comprised of a polymeric coupling layer with a low acoustic impedance (2-5 MRayl) sandwiched between two piezoceramic layers is investigated. Depending on the electrical configuration, the CRT exhibits two usable frequency bands. The resonance frequency of the high-frequency (HF) band can be tailored to be ~3-5 times higher than that of the low-frequency (LF) band using the stiffness in the coupling layer. The CRT's LF band was analyzed analytically, and we obtained the closed-form expressions for the LF resonance frequency. A dual-frequency CRT was designed, manufactured, and characterized acoustically, and comparisons with theory showed good agreement. The HF band exhibited a center frequency of 2.5 MHz with a -3-dB bandwidth of 70% and is suited to manipulate microbubbles or for diagnostic imaging applications. The LF band exhibited a center frequency of 0.5 MHz with a -3-dB bandwidth of 13% and is suited to induce biological effects in tissue, therein manipulation of microbubbles.

Dual Modality EIT-UTT for Water Dominate Three-Phase Material Imaging

Three-phase material imaging such as oil, gas and water is a critical problem in many processes. Monitoring and separation of each phase before corresponding process can be a key to realise cost efficiency production. In the oil and gas industry such a tool can generate great environmental benefits. In recent years, several multi-modality imaging systems are being adapted for such an application. It is not possible to gain information on three phase flow using a single imaging modality that can be deployed in production field. For a three-phase flow dominated by water phase, this is more challenging. The capability of the majority of current dual-modality systems was only demonstrated under limited flow regime conditions. This paper presents a novel combined imaging system including electrical impedance tomography (EIT), and ultrasound transmission tomography (UTT) for mapping three-phase flow. In water dominate mode, the EIT is able to image the nonconductive phases of oil and gas in a water dominate background phase, but not able to separate oil and gas. The EIT two-phase imaging then complimented with the speed of sound imaging of the UTT, which can separate liquid (oil and water) and gas. A dual modality EIT-UTT system combining a 32-electrode EIT array and a 32-transducer UTT sensor array is developed to demonstrate this novel three-phase material imaging. The concept was demonstrated using simulation study and then shown with experimental lab tests. Measurement principles and method are described, experiment based on several three-phase flow scenarios are established, and the results show successful distinguishably for all three phases.

Abstract B095: Mapping the genetic features of immune checkpoint responsiveness using AAV-CRISPR mediated in vivo screen

Abstract Immune checkpoint blockade has achieved tremendous clinical success across many tumor types, but fails to induce clinical responses in many patients. The mechanisms underlying checkpoint resistance remain poorly characterized. Recent studies have applied next generation sequencing techniques to catalog the mutational burden of patient tumors, which provides a wealth of data to determine common mutations. To map the genetic features of response to checkpoint blockade immunotherapy as well as correlating the clinical efficacy with certain mutations, we developed a novel direct in vivo CRISPR screening approach for high-throughput profiling of functional cancer drivers in an autochthonous manner by injecting AAVs carrying an sgRNA library targeting the top 50 TCGA pan-cancer recurrently mutated tumor suppressor genes (mTSG) into the immunocompetent Cas9 transgenic mice. All mice that received the AAV-mTSG library developed liver cancer and died within four months. We then utilized MIP sequencing of sgRNA target sites to chart the mutational landscape of these tumors, revealing the functional consequence of multiple variants in driving liver tumorigenesis as well as identifying specific gene pairs that were co-occurring across mice. Using this approach, we also mapped the mutation landscape changes under the pressures of immune checkpoint inhibitors, anti-PD1 or anti-CTLA4. We monitored liver tumor growth in AAV-mTSG injected LSL-Cas9;LSL-Fluc mice by using intravital bioluminescent imaging system (IVIS) in combination with dissection check before drug administration. Using IVIS data, we grouped them into 3 size-matched cohorts to receive anti-PD1 or anti-CTLA4 treatments or PBS control. According to the survival data, the mice with mTSG-induced liver tumor benefit from anti-PD1 or anti-CLTA4 treatment. By comparing the mutation frequencies of liver tumors in the mice receiving either checkpoint inhibitors or PBS treatment, we mapped the mutation landscape changes associated with anti-PD1 or anti-CTLA4 treatment. We are performing validation studies on top targets such as Arid1a, Stk11, and B2M. Using this approach, we systematically mapped the correlation of these top 50 driver mutations with cancer immune evasion and immunotherapy responsiveness, providing a valuable reference for patient stratification when considering immunotherapy as well as novel targets for synergistic interventions. Citation Format: Guangchuan Wang, Ryan Chow, Zhigang Bai, Lupeng Ye, Sidi Chen. Mapping the genetic features of immune checkpoint responsiveness using AAV-CRISPR mediated in vivo screen [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B095.

Correcting Cherenkov light attenuation in tissue using spatial frequency domain imaging for quantitative surface dosimetry during whole breast radiation therapy.

.Imaging Cherenkov emission during radiotherapy permits real-time visualization of external beam delivery on superficial tissue. This signal is linear with absorbed dose in homogeneous media, indicating potential for quantitative dosimetry. In humans, the inherent heterogeneity of tissue optical properties (primarily from blood and skin pigment) distorts the linearity between detected Cherenkov signal and absorbed dose. We examine the potential to correct for superficial vasculature using spatial frequency domain imaging (SFDI) to map tissue optical properties for large fields of view. In phantoms, applying intensity corrections to simulate blood vessels improves Cherenkov image (CI) negative contrast by 24% for a vessel 1.9-mm-in diameter. In human trials, SFDI and CI are acquired for women undergoing whole breast radiotherapy. Applied corrections reduce heterogeneity due to vasculature within the sampling limits of the SFDI from a 22% difference as compared to the treatment plan, down to 6% in one region and from 14% down to 4% in another region. The optimal use for this combined imaging system approach is to correct for small heterogeneities such as superficial blood vessels or for interpatient variations in blood/melanin content such that the corrected CI more closely represents the surface dose delivered.