A non-invasive approach to skin cancer diagnosis via graphene electrical tattoos and electrical impedance tomography.

Objective.Making up one of the largest shares of diagnosed cancers worldwide, skin cancer is also one of the most treatable. However, this is contingent upon early diagnosis and correct skin cancer-type differentiation. Currently, methods for early detection that are accurate, rapid, and non-invasive are limited. However, literature demonstrating the impedance differences between benign and malignant skin cancers, as well as between different types of skin cancer, show that methods based on impedance differentiation may be promising.Approach.In this work, we propose a novel approach to rapid and non-invasive skin cancer diagnosis that leverages the technologies of difference-based electrical impedance tomography (EIT) and graphene electronic tattoos (GETs).Main results.We demonstrate the feasibility of this first-of-its-kind system using both computational numerical and experimental skin phantom models. We considered variations in skin cancer lesion impedance, size, shape, and position relative to the electrodes and evaluated the impact of using individual and multi-electrode GET (mGET) arrays. The results demonstrate that this approach has the potential to differentiate based on lesion impedance, size, and position, but additional techniques are needed to determine shape.Significance.In this way, the system proposed in this work, which combines both EIT and GET technology, exhibits potential as an entirely non-invasive and rapid approach to skin cancer diagnosis.

Corneal thickness evaluation in healthy eyes: Comparison between two different Scheimpflug devices.

PURPOSE: To evaluate the correlation between corneal thickness (CT) measurements obtained with two Scheimpflug devices, Pentacam HR and Precisio, and to elaborate, if necessary, a regression formula which could make these results comparable. DESIGN: Retrospective, Comparative, Observational study. SETTING: Department of Medicine, Surgery and Dentistry, "Scuola Medica Salernitana" University of Salerno, Italy. METHODS: One hundred twenty four healthy eyes of 124 volunteers (65 males; range: 20-32 years; mean age of 24.8 ± 1.7) were included in this study. CT was measured using Pentacam HR and Precisio in three different points: the pupil center (PC), the corneal apex (CA) and the thinnest point (TP). RESULTS: CT obtained with both devices at the PC, at the CA and at the TP showed a good correlation (r = 0.97, r = 0.97, r = 0.97, respectively), but Pentacam HR measurements were significantly thicker than those provided by Precisio (p < 0.01). The differences between Pentacam HR and Precisio were 21.9 ± 8.8 µm at the PC, 21.9 ± 8.9 µm at the CA, 19.1 ± 9.0 µm at the TP. The calculated regression formulas were: y = 0.9558x + 2.3196 for the PC, y = 0.9519x + 4.5626 for the CA, y = 0.9364x + 15.436 for the TP, where x is the CT measured with Pentacam HR and y is the Precisio measurement. CONCLUSIONS: The findings provided by this study highlight that Precisio measures thinner corneas compared to Pentacam HR. The identified regression formulas could be utilized to make interchangeable the results obtained with these two devices.

The experimental study of mouse liver in magneto-acousto-electrical tomography by scan mode.

Magneto-acousto-electrical tomography (MAET) is an imaging method coupled with sound field and magnetic field. The aim of this study is to present some novel experimental results of the mouse liver for the magneto-acousto-electrical tomography measured by two electrodes. The magnetic field in the space of 60 mm3 is about 300 mT which generate by two permanent magnets. A plane transducer with 2.25 MHz center frequency is utilized to generate acoustic waves inside the object. The signal is detected by two similar 1 mm copper foil electrodes. An amplifier is designed to receive the MAET signal, and the gain of the amplifier is adjusted to be 54 dB. The phantom used in this paper is a mouse liver surrounded by a gel phantom with the conductivity of 0.7 S m-1. The gel phantom with the conductivity of 0.7 S m-1 is used to simulate the liver tumor, and the normal mouse liver is filled in the phantom. A series of the MAET signals are detected by the electrodes when the transducer is moved on a pre-set line route, then a B-scan image is realized. The experimental system can provide more information about the tumor and the results show that the MAET is sensitive enough for the potential clinical application of tumor in animal or human.

A 1 MHz Miniaturized Electrical Impedance Tomography System for Prostate Imaging.

An ASIC for a high frequency electrical impedance tomography (EIT) imaging system for prostate cancer screening is presented. The ASIC enables a small form-factor architecture, which ensures high signal-to-noise ratio (SNR) at MHz frequencies. The 4-channel ASIC was designed and fabricated in a standard CMOS 0.18- µm technology and integrates a novel current driver for current stimulus, instrumentation amplifier to interface with the tissue, VGA to provide variable gain and ADC with SPI interface for digitization. A prototype miniaturized EIT system was built and it was evaluated using a model transrectal imaging probe immersed into a tank filled with saline and a metal inclusion that demonstrated the open-domain problem of imaging prostate cancer lesion. The system maintained an SNR between 66 and 76 dB over the frequency range of 500 Hz to 1 MHz. Also, it produced reconstructed EIT images that depicted the presence of the small metal inclusion that modeled a prostate cancer imaging application.

Screening Candidates for Refractive Surgery With Corneal Tomographic-Based Deep Learning.

Importance: Evaluating corneal morphologic characteristics with corneal tomographic scans before refractive surgery is necessary to exclude patients with at-risk corneas and keratoconus. In previous studies, researchers performed screening with machine learning methods based on specific corneal parameters. To date, a deep learning algorithm has not been used in combination with corneal tomographic scans. Objective: To examine the use of a deep learning model in the screening of candidates for refractive surgery. Design, Setting, and Participants: A diagnostic, cross-sectional study was conducted at the Zhongshan Ophthalmic Center, Guangzhou, China, with examination dates extending from July 18, 2016, to March 29, 2019. The investigation was performed from July 2, 2018, to June 28, 2019. Participants included 1385 patients; 6465 corneal tomographic images were used to generate the artificial intelligence (AI) model. The Pentacam HR system was used for data collection. Interventions: The deidentified images were analyzed by ophthalmologists and the AI model. Main Outcomes and Measures: The performance of the AI classification system. Results: A classification system centered on the AI model Pentacam InceptionResNetV2 Screening System (PIRSS) was developed for screening potential candidates for refractive surgery. The model achieved an overall detection accuracy of 94.7% (95% CI, 93.3%-95.8%) on the validation data set. Moreover, on the independent test data set, the PIRSS model achieved an overall detection accuracy of 95% (95% CI, 88.8%-97.8%), which was comparable with that of senior ophthalmologists who are refractive surgeons (92.8%; 95% CI, 91.2%-94.4%) (P = .72). In distinguishing corneas with contraindications for refractive surgery, the PIRSS model performed better than the classifiers (95% vs 81%; P < .001) in the Pentacam HR system on an Asian patient database. Conclusions and Relevance: PIRSS appears to be useful in classifying images to provide corneal information and preliminarily identify at-risk corneas. PIRSS may provide guidance to refractive surgeons in screening candidates for refractive surgery as well as for generalized clinical application for Asian patients, but its use needs to be confirmed in other populations.

Corneal aberrations measured with a high-resolution Scheimpflug tomographer: repeatability and reproducibility.

PURPOSE: To evaluate the precision of elevation and wavefront aberration measurements with the Pentacam HR (Oculus Optikgeräte GmbH). SETTING: Flinders University, Australia. DESIGN: Instrument evaluation study. METHODS: A randomly selected eye of 100 participants was scanned twice with the Pentacam HR by 1 observer on the 3 measurement modes: 25-picture, 50-picture, and cornea fine. A second observer performed 2 scans on the same random eye with the 25-picture mode. Repeatability and reproducibility were assessed using the within-subject SD (Sw) statistic from a 1-way analysis of variance. RESULTS: From the 100 scanned eyes, the higher-order aberration root mean square (RMS) repeatability limit for both elevation and wavefront, and anterior and posterior measurements was 0.03 µm for all 3 measurement modes. Anterior, posterior, and total corneal wavefront Zernike terms were highly precise, with most Zernike terms displaying a repeatability limit of 0.03 µm. The least repeatable measurement was the posterior elevation Zernike term with the 25-picture scan (repeatability limit 1.50 µm). The cornea fine measurement mode provided the most precise measurements. Reproducibility limits (second observer) were similar to repeatability limits with the 25-picture scan mode. CONCLUSIONS: The Pentacam HR provided highly precise aberration outputs. The most precise measurements are achievable with the cornea fine measurement mode and wavefront aberrations. One should be cognizant of posterior elevation aberration precision, particularly for lower radial order and higher azimuthal frequency terms. Accounting for tilt and misalignment of aberrations, all RMS and Zernike aberrations were extremely precise (repeatability and reproducibility limit less than 0.000001 µm).

Managing erroneous measurements of dynamic brain electrical impedance tomography after reconnection of faulty electrodes.

OBJECTIVE: Electrode detachment may occur during dynamic brain electrical impedance tomography (EIT) measurements. After the faulty electrodes have been reset, EIT can restore to steady monitoring but the corrupted data, which will challenge interpretation of the results, are notoriously difficult to recover. APPROACH: Here, a piecewise processing method (PPM) is introduced to manage the erroneous EIT data after reattachment of faulty electrodes. In the PPM, we define the three phases before, during and after reconnection of the faulty electrode as PI, PII and PIII, respectively. Using this definition, an empirical mode decomposition-based interpolation method is introduced to compensate the corrupted data in PII, using the valid measurements in PI and PIII. Then, the compensated data in PII are spliced at the end of PI. Thus, there will be a surge at the junction of PII and PIII due to the changes in contact state of the repositioned electrodes. Finally, to ensure all the EIT data are obtained under constant electrode settings, we calculate the above changes and eliminate them from the data after PII. To verify the performance of the PPM, experiments based on head models, with anatomical structures and with human subjects were conducted. Metrics including permutation entropy (PE) and image correlation (IC) were proposed to measure the stability of the signal and the quality of the reconstructed EIT images, respectively. MAIN RESULTS: The results demonstrated that the PE of the processed data was reduced to 0.25 and the IC improved to 0.78. SIGNIFICANCE: Without iterative calculations the PPM could efficiently manage the erroneous EIT data after reattachment of the faulty electrodes.

Navigated non-contact fluorescence tomography.

A non-contact approach for diffuse optical tomography (DOT) has been developed for on-demand image updates using surgical navigation technology. A stereoscopic optical tracker provides real-time localization of reflective spheres mounted to a laser diode and near-infrared camera. Standard camera calibration is combined with tracking data to determine the intrinsic camera parameters (focal length, principal point and non-linear lens distortion) and the tracker-to-camera transform. Tracker-to-laser calibration is performed using images of laser beam intersection with a tracked calibration surface. Source and detector positions for a finite-element DOT implementation are projected onto the boundary elements of the tissue mesh by finding ray-triangle intersections. A multi-stage model converts camera counts to surface flux by accounting for lens aperture settings, fluorescence filter transmittance, photodetector quantum efficiency, photon energy, exposure time, readout offset and camera gain. The image-guidance framework was applied to an in-house optical tomography system configured for indocyanine green (ICG) fluorescence. Mean target registration errors for camera and laser calibration were less than 1 mm. Surface flux measurements of total reflectance and fluorescence in Intralipid-based fluorescence phantoms (0-2 µg ml-1) had mean errors of 3.1% and 4.4%, respectively, relative to diffusion theory predictions. Spatially-resolved reflectance measurements in a calibrated optical phantom agreed with theory for radial distances up to 25 mm from the laser source. Inverse fluorescence reconstructions of a sub-surface fluorescence target confirmed the localization accuracy (average target centroid error of 0.44 mm). This translational research system is under investigation for clinical applications in head and neck surgery, including oral cavity tumor resection, lymph node mapping and free-flap perforator assessment.

Miniature fluorescence molecular tomography (FMT) endoscope based on a MEMS scanning mirror and an optical fiberscope.

We present a novel FMT endoscope by using a MEMS scanning mirror and an optical fiberscope. The diameter of this highly miniaturized FMT device is only 5 mm. To our knowledge, this is the smallest FMT device we found so far. Several phantom experiments based on indocyanine green (ICG) were conducted to demonstrate the imaging ability of this device. Two tumor-bearing mice were systematically injected with tumor-targeted NIR fluorescent probes (ATF-PEG-IO-830) and were then imaged to further demonstrate the ability of this FMT endoscope for imaging small animals.

All-reflective ring illumination system for photoacoustic tomography.

Given that breast cancer is the second leading cause of cancer-related deaths among women in the United States, it is necessary to continue improving the sensitivity and specificity of breast imaging systems that diagnose breast lesions. Photoacoustic (PA) imaging can provide functional information during in vivo studies and can augment the structural information provided by ultrasound (US) imaging. A full-ring, all-reflective, illumination system for photoacoustic tomography (PAT) coupled to a full-ring US receiver is developed and tested. The US/PA tomography system utilizes a cone mirror and conical reflectors to optimize light delivery for PAT imaging and has the potential to image objects that are placed within the ring US transducer. The conical reflector used in this system distributes the laser energy over a circular cross-sectional area, thereby reducing the overall fluence. This, in turn, allows the operator to increase the laser energy achieving better cross-sectional penetration depth. A proof-of-concept design utilizing a single cone mirror and a parabolic reflector is used for imaging cylindrical phantoms with light-absorbing objects. For the given phantoms, it has been shown that there was no restriction in imaging a given targeted cross-sectional area irrespective of vertical depth, demonstrating the potential of mirror-based, ring-illuminated PAT system. In addition, the all-reflective ring illumination method shows a uniform PA signal across the scanned cross-sectional area.

Quantitative assessment of breast density using transmission ultrasound tomography.

PURPOSE: Breast density is important in the evaluation of breast cancer risk. At present, breast density is evaluated using two-dimensional projections from mammography with or without tomosynthesis using either (a) subjective assessment or (b) a computer-aided approach. The purpose of this work is twofold: (a) to establish an algorithm for quantitative assessment of breast density using quantitative three-dimensional transmission ultrasound imaging; and (b) to determine how these quantitative assessments compare with both subjective and objective mammographic assessments of breast density. METHODS: We described and verified a threshold-based segmentation algorithm to give a quantitative breast density (QBD) on ultrasound tomography images of phantoms of known geometric forms. We also used the algorithm and transmission ultrasound tomography to quantitatively determine breast density by separating fibroglandular tissue from fat and skin, based on imaged, quantitative tissue characteristics, and compared the quantitative tomography segmentation results with subjective and objective mammographic assessments. RESULTS: Quantitative breast density (QBD) measured in phantoms demonstrates high quantitative accuracy with respect to geometric volumes with average difference of less than 0.1% of the total phantom volumes. There is a strong correlation between QBD and both subjective mammographic assessments of Breast Imaging - Reporting and Data System (BI-RADS) breast composition categories and Volpara density scores - the Spearman correlation coefficients for the two comparisons were calculated to be 0.90 (95% CI: 0.71-0.96) and 0.96 (95% CI: 0.92-0.98), respectively. CONCLUSIONS: The calculation of breast density using ultrasound tomography and the described segmentation algorithm is quantitatively accurate in phantoms and highly correlated with both subjective and Food and Drug Administration (FDA)-cleared objective assessments of breast density.

Current-conveyor-based wide-band current driver for electrical impedance tomography.

OBJECTIVE: In this paper a wide-band integrated current driver for electrical impedance tomography (EIT) is presented. The application is primarily for prostate and breast cancer detection which require the tissue to be interrogated at frequencies up to 10 MHz while achieving low harmonic distortion and high accuracy. APPROACH: The current driver is based on current conveyor architecture and can deliver 1.2 mA of peak to peak ac current between frequencies of 100 Hz-10 MHz. It is fabricated in CMOS 0.18 [Formula: see text]m technology with a power supply of 3.3 V, and occupies a core area of 0.26 [Formula: see text]. MAIN RESULTS: The measured harmonic distortion for a peak current of 1.2 mA is <[Formula: see text] for frequencies less than 100 kHz, and increases to [Formula: see text] at 10 MHz. The measured output impedance of the current driver is 101 k[Formula: see text] at 1 MHz and 19.5 k[Formula: see text] at 10 MHz. SIGNIFICANCE: The circuit is suitable for high frequency active electrode applications.

3-D Microwave Tomography Using the Soft Prior Regularization Technique: Evaluation in Anatomically Realistic MRI-Derived Numerical Breast Phantoms.

OBJECTIVE: Fusion of magnetic resonance imaging (MRI) breast images with microwave tomography is accomplished through a soft prior technique, which incorporates spatial information (from MRI), i.e., accurate boundary location of different regions of interest, into the regularization process of the microwave image reconstruction algorithm. METHODS: Numerical experiments were completed on a set of three-dimensional (3-D) breast geometries derived from MR breast data with different parenchymal densities, as well as a simulated tumor to evaluate the performance over a range of breast shapes, sizes, and property distributions. RESULTS: When the soft prior regularization technique was applied, both permittivity and conductivity relative root mean square error values decreased by more than 87% across all breast densities, except in two cases where the error decrease was only 55% and 78%. In addition, the incorporation of structural priors increased contrast between tumor and fibroglandular tissue by 59% in permittivity and 192% in conductivity. CONCLUSION: This study confirmed that the soft prior algorithm is robust in 3-D and can function successfully across a range of complex geometries and tissue property distributions. SIGNIFICANCE: This study demonstrates that our microwave tomography is capable of recovering accurate tissue property distributions when spatial information from MRI is incorporated through soft prior regularization.

Visualising peripheral arterioles and venules through high-resolution and large-area photoacoustic imaging.

Photoacoustic (PA) imaging (PAI) has been shown to be a promising tool for non-invasive blood vessel imaging. A PAI system comprising a hemispherical detector array (HDA) has been reported previously as a method providing high morphological reproducibility. However, further improvements in diagnostic capability will require improving the image quality of PAI and fusing functional and morphological imaging. Our newly developed PAI system prototype not only enhances the PA image resolution but also acquires ultrasonic (US) B-mode images at continuous positions in the same coordinate axes. In addition, the pulse-to-pulse alternating laser irradiation shortens the measurement time difference between two wavelengths. We scanned extremities and breasts in an imaging region 140 mm in diameter and obtained 3D-PA images of fine blood vessels, including arterioles and venules. We could estimate whether a vessel was an artery or a vein by using the S-factor obtained from the PA images at two wavelengths, which corresponds approximately to the haemoglobin oxygen saturation. Furthermore, we observed tumour-related blood vessels around breast tumours with unprecedented resolution. In the future, clinical studies with our new PAI system will help to elucidate various mechanisms of vascular-associated diseases and events.

Small near-infrared photochromic protein for photoacoustic multi-contrast imaging and detection of protein interactions in vivo.

Photoacoustic (PA) computed tomography (PACT) benefits from genetically encoded probes with photochromic behavior, which dramatically increase detection sensitivity and specificity through photoswitching and differential imaging. Starting with a DrBphP bacterial phytochrome, we have engineered a near-infrared photochromic probe, DrBphP-PCM, which is superior to the full-length RpBphP1 phytochrome previously used in differential PACT. DrBphP-PCM has a smaller size, better folding, and higher photoswitching contrast. We have imaged both DrBphP-PCM and RpBphP1 simultaneously on the basis of their unique signal decay characteristics, using a reversibly switchable single-impulse panoramic PACT (RS-SIP-PACT) with a single wavelength excitation. The simple structural organization of DrBphP-PCM allows engineering a bimolecular PA complementation reporter, a split version of DrBphP-PCM, termed DrSplit. DrSplit enables PA detection of protein-protein interactions in deep-seated mouse tumors and livers, achieving 125-µm spatial resolution and 530-cell sensitivity in vivo. The combination of RS-SIP-PACT with DrBphP-PCM and DrSplit holds great potential for noninvasive multi-contrast deep-tissue functional imaging.

Experimental fluence-modulated proton computed tomography by pencil beam scanning.

PURPOSE: This experimental study is aimed at demonstrating, using a simple cylindrical water phantom, the feasibility of fluence-modulated proton computed tomography (FMpCT) by pencil beam scanning (PBS) proton computed tomography (pCT). METHODS: The phase II pCT prototype of the Loma Linda U. and U. C. Santa Cruz was operated using the PBS beam line of the Northwestern Medicine Chicago Proton Center. A 20 × 10 grid of 1.37 cm full width half maximum pencil beams (PB) equally spaced by 1 cm was used to acquire 45 projections in step and shoot mode. The PB pattern's fluence was modified to allow FMpCT scans with fluence modulation factors (FMF) of 50% and 20%. A central FMpCT region of interest (FMpCT-ROI) was used to define a high image quality region. Reconstructed images were evaluated in terms of relative stopping power (RSP) accuracy and noise using annular ROIs. The FMpCT dose savings were estimated by Monte Carlo (MC) simulation of the pCT acquisitions using beam phase space distributions. PBS pCT results with homogeneous fluence were additionally compared to broad beam results in terms of RSP accuracy and noise. RESULTS: PBS pCT scans with acceptable pileup were possible, and images were comparable to previously acquired broad beam pCT images in terms of both noise and accuracy. In the FMpCT-ROI, the noise and accuracy from full fluence (FF) scans were preserved. Dose savings of up to 60% were achieved at the object's edge when using FMF of 20%. CONCLUSION: In this study, we have demonstrated that PBS pCT scans can achieve equivalent accuracy as those obtained from broad beams. The feasibility of FMpCT scans was demonstrated; image accuracy and noise were successfully preserved in the central FMpCT-ROI chosen for this study, and dose reduction of up to 60% at the object's edge was realized.

Atrial myxoma in a patient with patent foramen ovale: evaluation with multimodal imaging. Case report / Mixoma auricular en un paciente con foramen oval permeable: evaluación con imágenes multimodales. Reporte de un caso

Abstract: Primary cardiac tumors in adults are rare and mostly benign, approximately 75%, being the myxoma the most frequent in half of that percentage. One-fourth of the primary cardiac tumors are malignant and 95% of the cases are sarcomas. Metastases are more frequent than primary tumors. Cardiac surgery is indicated specially in benign masses and therapies such as chemotherapy and/or radiotherapy should be reserved for unresectable or metastatic malignancies. Hence the importance of a diagnostic approach, which leads to the best therapeutic conduct and in many cases, a multimodal image approach is necessary, as it is exposed in our case.(AU)

Resumen: Los tumores cardiacos primarios en adultos son raros y en su mayoría benignos, aproximadamente el 75%, siendo el mixoma el más frecuente en la mitad de ese porcentaje. Un cuarto de los tumores cardiacos primarios son malignos y el 95% de los casos son sarcomas. Las metástasis son más frecuentes que los tumores primarios. La cirugía cardiaca está indicada especialmente en masas benignas y las terapias como la quimioterapia y/o la radioterapia deben reservarse para tumores malignos o metástasis irresecables. De ahí la importancia de un enfoque de diagnóstico, que conduzca a la mejor conducta terapéutica y, en muchos casos, es necesario un enfoque de imagen multimodal, como está expuesto en nuestro caso.(AU)

Full-angle tomographic phase microscopy of flowing quasi-spherical cells.

We report a reliable full-angle tomographic phase microscopy (FA-TPM) method for flowing quasi-spherical cells along microfluidic channels. This method lies in a completely passive optical system, i.e. mechanical scanning or multi-direction probing of the sample is avoided. It exploits the engineered rolling of cells while they are flowing along a microfluidic channel. Here we demonstrate significant progress with respect to the state of the art of in-flow TPM by showing a general extension to cells having almost spherical shapes while they are flowing in suspension. In fact, the adopted strategy allows the accurate retrieval of rotation angles through a theoretical model of the cells' rotation in a dynamic microfluidic flow by matching it with phase-contrast images resulting from holographic reconstructions. So far, the proposed method is the first and the only one that permits to get in-flow TPM by probing the cells with full-angle, achieving accurate 3D refractive index mapping and the simplest optical setup, simultaneously. Proof of concept experiments were performed successfully on human breast adenocarcinoma MCF-7 cells, opening the way for the full characterization of circulating tumor cells (CTCs) in the new paradigm of liquid biopsy.

A novel CXCR4-targeted near-infrared (NIR) fluorescent probe (Peptide R-NIR750) specifically detects CXCR4 expressing tumors.

C-X-C chemokine receptor 4 (CXCR4) is over-expressed in multiple human cancers and correlates with tumor aggressiveness, poor prognosis and increased risk for distant metastases. Imaging agents for CXCR4 are thus highly desirable. We developed a novel CXCR4-targeted near-infrared (NIR) fluorescent probe (Peptide R-NIR750) conjugating the new developed CXCR4 peptidic antagonist Peptide R with the NIR fluorescent dye VivoTag-S750. Specific CXCR4 binding was obtained in cells overexpressing human CXCR4 (B16-hCXCR4 and human melanoma cells PES43), but not in CXCR4 low expressing cells (FB-1). Ex vivo evaluation demonstrated that PepR-NIR750 specifically detects B16-hCXCR4-derived subcutaneous tumors and lung metastases. Fluorescence Molecular Tomography (FMT) in vivo imaging was performed on mice carrying subcutaneous CHO and CHO-CXCR4 tumors. PepR-NIR750 accumulates only in CXCR4-positive expressing subcutaneous tumors. Additionally, an intense NIR fluorescence signal was detected in PES43-derived lung metastases of nude mice injected with PepR-NIR750 versus mice injected with VivoTag-S750. With a therapeutic intent, mice bearing PES43-derived lung metastases were treated with Peptide R. A the dramatic reduction in PES43-derived lung metastases was detected through a decrease of the PepR-NIR750 signal. PepR-NIR750 is a specific probe for non-invasive detection of human high CXCR4-expressing tumors and metastatic lesion and thus a valuable tool for cancer molecular imaging.

Phantom experiments using soft-prior regularization EIT for breast cancer imaging.

OBJECTIVE: A soft-prior regularization (SR) electrical impedance tomography (EIT) technique for breast cancer imaging is described, which shows an ability to accurately reconstruct tumor/inclusion conductivity values within a dense breast model investigated using a cylindrical and a breast-shaped tank. APPROACH: The SR-EIT method relies on knowing the spatial location of a suspicious lesion initially detected from a second imaging modality. Standard approaches (using Laplace smoothing and total variation regularization) without prior structural information are unable to accurately reconstruct or detect the tumors. The soft-prior approach represents a very significant improvement to these standard approaches, and has the potential to improve conventional imaging techniques, such as automated whole breast ultrasound (AWB-US), by providing electrical property information of suspicious lesions to improve AWB-US's ability to discriminate benign from cancerous lesions. MAIN RESULTS: Specifically, the best soft-regularization technique found average absolute tumor/inclusion errors of 0.015 S m-1 for the cylindrical test and 0.055 S m-1 and 0.080 S m-1 for the breast-shaped tank for 1.8 cm and 2.5 cm inclusions, respectively. The standard approaches were statistically unable to distinguish the tumor from the mammary gland tissue. An analysis of false tumors (benign suspicious lesions) provides extra insight into the potential and challenges EIT has for providing clinically relevant information. SIGNIFICANCE: The ability to obtain accurate conductivity values of a suspicious lesion (>1.8 cm) detected from another modality (e.g. AWB-US) could significantly reduce false positives and result in a clinically important technology.