3D Reference Research Articles

TH-E-211-05: Reference Dosimetry during Diagnostic CT Examination Using XR-QA Radiochromic Film Model

Purpose: We applied 2D reference dosimetry protocol for dose measurements using XR‐QA radiochromic film model during diagnostic computed tomography(CT) examinations carried out on patients and humanoid Rando phantom. Methods: Response of XR‐QA model GAFCHROMIC™ film reference dosimetry system was calibrated in terms of Air‐Kerma in air. Four most commonly used CT protocols were selected on our scanner(GE Lightspeed VCT 64), covering 3 anatomical sites (Head, Chest, and Abdomen). For each protocol, 25 patients ongoing planned diagnostic CT examination were recruited. Surface dose was measured using 4 or 8 strips taped on patients' skin and on Rando phantom. Film pieces were scanned prior to and after irradiation using Epson Expression™ 10000XL document scanner. Optical reflectance of the unexposed film piece was subtracted from exposed one to obtain final net reflectance change, which is subsequently converted to dose using previously established calibration curves. Results: Our measurements show that skin dose variation has a sinusoidal pattern along the scanning axis due to the helical movement of the X‐ray tube around body, and axial movement with pitch around head. Preliminary results show that the average skin dose for patients can be up to 6.8 cGy, 7.6 cGy, 6.0 cGy and 7.0 cGy for Head, Chest, Abdomen and Angio Abdomen protocol. The obtained experimental Dose‐Length Products (DLP) show higher values than CT based DLP taken from the scanner console. Conclusions: In this work, we applied an Air‐Kerma in air based radiochromic film reference dosimetry protocol for in vivo skin dose measurements. We found that green channel extracted from the scanned RGB image is the best suited for dose measurements in the range from 0 to 20 cGy. Measuredskin doses and corresponding DLPs are larger than provided by the manufacturers since they are measured on the skin of the patients.

Hydration Thermodynamics Using the Reference Interaction Site Model: Speed or Accuracy?

We report a method to dramatically improve the accuracy of hydration free energies (HFE) calculated by the 1D and 3D reference interaction site models (RISM) of molecular integral equation theory. It is shown that the errors in HFEs calculated by RISM approaches using the Gaussian fluctuations (GF) free energy functional are not random, but can be decomposed into linear combination of contributions from different structural elements of molecules (number of double bonds, number of OH groups, etc.). Therefore, by combining RISM/GF with cheminformatics, one can develop an accurate method for HFE prediction. We call this approach the structural description correction model (SDC) ( Ratkova et al. J. Phys. Chem. B 2010 , 114 , 12068 ). In this work, we investigated the prediction quality of the SDC model combined with 1D and 3D RISM approaches. In parallel, we analyzed the computational performance of these two methods. The SDC model parameters were obtained by fitting against a training set of 53 simple organic molecules. To demonstrate that the values of these parameters were transferable between different classes of molecules, the models were tested against 98 more complex molecules (including 38 polyfragment compounds). The results show that the 3D RISM/SDC model predicts the HFEs with very good accuracy (RMSE of 0.47 kcal/mol), while the 1D RISM approach provides only moderate accuracy (RMSE of 1.96 kcal/mol). However, a single 1D RISM/SDC calculation takes only a few seconds on a PC, whereas a single 3D RISM/SDC HFE calculation is approximately 100 times more computationally expensive. Therefore, we suggest that one should use the 1D RISM/SDC model for large-scale high-throughput screening of molecular hydration properties, while further refinement of these properties for selected compounds should be carried out with the more computationally expensive but more accurate 3D RISM/SDC model.

Three-Dimensional Transesophageal Echocardiography of Atrial Septal Defect: A Qualitative and Quantitative Anatomic Study

Real-time three-dimensional (3D) transesophageal echocardiography (TEE) was used to analyze atrial septal defect (ASD) with 4 goals: (1) to determine feasibility, (2) to analyze the accuracy of qualitative and quantitative data, (3) to assess strengths and weaknesses of the available modes of 3D TEE, and (4) to provide 3D transesophageal echocardiographic reference images. Sixty-five patients with ASDs (age, 5-64 years; weight, 20-114 kg; body surface area, 0.8-2.4 m(2)) underwent 3D TEE during catheter intervention or surgery. Three-dimensional transesophageal echocardiographic formats included live 3D, 3D zoom, and full-volume 3D modes. Qualitative and quantitative analysis of the 3D data was compared with two-dimensional echocardiographic data and intraoperative inspection. Diagnostic-quality 3D TEE was successfully performed in all 65 patients. Fifty had secundum ASDs and 15 had other ASD types (seven sinus venosus, six primum, one common atrium, and one coronary sinus ASD). ASD type and location were correctly diagnosed in all patients. ASD shape and orientation were confirmed in 21 patients at surgery. Quantitative analysis of ASDs successfully demonstrated rims and changes in dimensions from systole to diastole. Live 3D mode had the highest volume rate, the best transgastric views, and the best views during device deployment but was limited by small sector size. Three-dimensional zoom mode allowed precropped live 3D images but was limited by slow volume rate. Full-volume mode had the best views of large defects and surrounding anatomy. However, it was limited by stitch artifact and required postacquisition cropping. Three-dimensional TEE is feasible and accurate. Each of the 3D transesophageal echocardiographic modalities has strengths and limitations.

Mass Spectrometric Characterization of Protein Structure Details Refines the Proteome Signature for Invasive Ductal Breast Carcinoma

Early diagnosis as well as individualized therapies are necessary to reduce the mortality of breast cancer, and personalized patient care strategies rely on novel prognostic or predictive factors. In this study, with six breast cancer patients, 2D gel analysis was applied for studying protein expression differences in order to distinguish invasive ductal breast carcinoma, the most frequent breast tumor subtype, from control samples. In total, 1203 protein spots were assembled in a 2D reference gel. Differentially abundant spots were subjected to peptide mass fingerprinting for protein identification. Twenty proteins with their corresponding 38 differentially expressed 2D gel spots were contained in our previously reported proteome signature, suggesting that distinct protein forms were contributing. In-depth MS/MS measurements enabled analyses of protein structure details of selected proteins. In protein spots that significantly contributed to our signature, we found that glyceraldehyde-3-phosphate dehydrogenase was N-terminally truncated, pyruvate kinase M2 and nucleoside diphosphate kinase A but not other isoforms of these proteins were of importance, and nucleophosmin phosphorylation at serine residues 106 and 125 were clearly identified. Principle component analysis and hierarchical clustering with normalized quantitative data from the 38 spots resulted in accurate separation of tumor from control samples. Thus, separation of tissue samples as in our initial proteome signature could be confirmed even with a different proteome analysis platform. In addition, detailed protein structure investigations enabled refining our proteome signature for invasive ductal breast carcinoma, opening the way to structure-/function studies with respect to disease processes and/or therapeutic intervention.

3D Face Reconstruction from a Single Image Using a Single Reference Face Shape

Human faces are remarkably similar in global properties, including size, aspect ratio, and location of main features, but can vary considerably in details across individuals, gender, race, or due to facial expression. We propose a novel method for 3D shape recovery of faces that exploits the similarity of faces. Our method obtains as input a single image and uses a mere single 3D reference model of a different person's face. Classical reconstruction methods from single images, i.e., shape-from-shading, require knowledge of the reflectance properties and lighting as well as depth values for boundary conditions. Recent methods circumvent these requirements by representing input faces as combinations (of hundreds) of stored 3D models. We propose instead to use the input image as a guide to "mold" a single reference model to reach a reconstruction of the sought 3D shape. Our method assumes Lambertian reflectance and uses harmonic representations of lighting. It has been tested on images taken under controlled viewing conditions as well as on uncontrolled images downloaded from the Internet, demonstrating its accuracy and robustness under a variety of imaging conditions and overcoming significant differences in shape between the input and reference individuals including differences in facial expressions, gender, and race.

Three-dimensional reference and stereotactic atlas of human cerebrovasculature from 7 Tesla

Although there exist some reference and stereotactic anatomical human brain atlases, there is no equivalent cerebrovascular atlas. A 3D reference atlas of the human cerebrovasculature that is interactive, stereotactic, very detailed, completely parcellated, fully labeled, extendable, dissectible, deformable, and user friendly, is needed in education, training, research, and clinical applications.We constructed a sophisticated and very detailed cerebrovascular atlas with 1325 vascular segments, the smallest of 80μm in diameter. The atlas was created from multiple 3 and 7T scans by employing tools and methods developed in our lab. In contrast to a sort of “sampled” vascular geometry cited in the literature, we provide information about the “continuous” geometry of the vascular model measurable in 3D at every location and along any vascular segment for both hemispheres.This cerebrovascular atlas was validated taking into account domain knowledge from various fields including angiography, neurosurgery, neuroradiology, (clinical) neuroanatomy, and terminology. Validation was considered as a confirmation of the created vascular model to a typical (conventional) cerebrovascular system with nearly average dimensions. It was done in terms of vessel subdivision, origin, course, surrounding anatomy, patterns, length, diameter, and branches. This validation demonstrates that the constructed cerebrovascular model generally represents a normal, typical cerebrovasculature with its dimensions close to average.This 7T atlas along with the vascular model is a rich source of knowledge about the human cerebrovasculature. The atlas is applicable in education, research, and clinical applications; it has already been applied in deep brain stimulation.

Relating function to structure: fMRI in (transgenic) mice and the Waxholm Space Reference System

Relating function to structure: fMRI in (transgenic) mice and the Waxholm Space Reference System

Damaged behavior under plane stress

This paper deals with the numerical treatment of advanced elasto-viscoplasticdamage constitutive equations in the particular case of plane stress. The viscoplastic constitutive equations account for the mixed isotropic and kinematic non linear hardening and are fully coupled with the isotropic ductile damage. The viscous effect is indifferently described by a power function (Norton type) or an hyperbolic sine function. Different time integration schemes are used and compared to each other assuming plane stress condition, widely used when dealing with shell structures as well as to the 3D reference case.

Eulerian and Lagrangian views of a turbulent boundary layer flow using time-resolved tomographic PIV

Coherent structures and their time evolution in the logarithmic region of a turbulent boundary layer investigated by means of 3D space–time correlations and time-dependent conditional averaging techniques are the focuses of the present paper. Experiments have been performed in the water tunnel at TU Delft measuring the particle motion within a volume of a turbulent boundary layer flow along a flat plate at a free-stream velocity of 0.53 m/s at Re ? = 2,460 based on momentum thickness by using time-resolved tomographic particle image velocimetry (PIV) at 1 kHz sampling rate and particle tracking velocimetry (PTV). The obtained data enable an investigation into the flow structures in a 3D Eulerian reference frame within time durations corresponding to 28 ?/U. An analysis of the time evolution of conditional averages of vorticity components representing inclined hairpin-like legs and of Q2- and Q4-events has been performed, which gives evidence to rethink the early stages of the classical hairpin development model for high Reynolds number TBLs. Furthermore, a PTV algorithm has been applied on the time sequences of reconstructed 3D particle image distributions identifying thousands of particle trajectories that enable the calculation of probability distributions of the three components of Lagrangian accelerations.

Indoor Hovering Control of Small Ducted-fan Type OAV Using Ultrasonic Positioning System

This study focused on a development of attitude stabilization and a position (hovering) control scheme of the SFR (Small Flying Robot). The platform type of the SFR is a ducted-fan type OAV having a diameter of 30 cm. The attitude of the SFR was successfully stabilized by a PD control method. In the attitude control loop, the feedback states were angle and angular rates, which were outputs from an AHRS (Attitude Heading Reference System). The position of the SFR was controlled precisely by the LQI (Linear Quadratic Integration) method with a Kalman filter. In the position control loop, an ultrasonic positioning system was used for the 3D position reference, which was developed in a previous research. The proposed simple mathematical model could analyze dynamics and stability of the SFR. Also, the stabilities of the attitude control and the precision of the position control were verified by comparing and analyzing data of experiments and simulations.

Comparison of segmentation methods for MRI measurement of cardiac function in rats

To establish the accuracy, intra- and inter-observer variabilities of four different segmentation methods for measuring cardiac functional parameters in healthy and infarcted rat hearts. Six Wistar rats were imaged before and after myocardial infarction using an electrocardiogram and respiratory-gated spoiled gradient echo sequence. Blinded and randomized datasets were analyzed by various semi-automatic and manual segmentation methods to compare their measurement bias and variability. In addition, the accuracy of these methods was assessed by comparison with reference measurements acquired from high-resolution three-dimensional (3D) datasets of a heart phantom. Relative inter- and intra-observer variability were found to be similar for all four methods. Semi-automatic segmentation methods reduced analysis time by up to 70%, while yielding similar measurement bias and variability compared with manual segmentation. Semi-automatic methods were found to underestimate the ejection fraction for healthy hearts compared with manual segmentation while overestimating them in infarcted hearts. However, semi-automatic segmentation of short axis slices agreed better with 3D reference scans of a heart phantom compared with manual segmentation. Semi-automatic segmentation methods are faster than manual segmentation, while offering a similar intra- and inter-observer variability. However, a potential bias has been observed between healthy and infarcted hearts for different methods, which should also be considered when selecting the most appropriate analysis technique.

Shape optimization of curved slots on 3D surface

In the aeronautic and aerospace thin-walled structures, hole shape designs are very popular to achieve the weight reduction, structural reparation, cooling and other purposes and have important influences on the structural weight, performances and fatigue life. Due to the fact that the hole shape optimization has to ensure the movement of the hole contour always located on the specific 3D surface, it is difficult to define reasonably the geometric design variables and the automatic design procedure of engineering simulation by means of existing design methodologies. The research group of Professor ZHANG WeiHong at Northwestern Polytechnical University, China has been dedicated to advanced optimization methods of aeronautic and aerospace lightweight structures for a long time. Recently, WANG Dan, Ph. D student, Professor ZHANG WeiHong, her supervisor and other research staffs deeply investigated the above problem in the paper “Shape optimization of 3D curved slots and its application to the squirrel-cage elastic support design”, which was published in SCIENCE CHINA Physics, Mechanics & Astronomy, (http://phys.scichina.com/) Volume 10, 2010. The squirrel-cage elastic support is one of the most important components of an aero-engine rotor system. A proper structural design will favor the static and dynamic performances of the system. This elastic support is a typical thin-walled structure of cylindrical surface on which a certain number of milling slots are distributed in a periodic way. Previous works related to the squirrel-cage elastic support design were mainly experience-based and focused on the vibration reduction and structure resistance analysis. However, practical applications indicate that the transition of a small circular arc on the rectangular slots will lead to an important stress concentration which will further initiate fatigue cracks and even sometimes break the cage strips. Yet, no related references exist about shape optimization of holes on such 3D surfaces. A new parametrical mapping method is proposed by the research team of Professor ZHANG Weihong. The essential idea is to define geometrical design variables in the 2D reference coordinate system for the description of 3D curved contours. Mathematical demonstrations show that this approach ensures that the curved contours are automatically located on the prescribed 3D surface. As a result, the 3D design problem is equivalently transformed into a 2D parametric problem. Finally, slot shape optimization of the aero-engine squirrel-cage elastic supports is successfully performed by this approach. Three kinds of slot contour shapes, i.e., one-directional symmetrical shapes, bi-directional symmetrical shapes and elliptical shapes are used to test the approach. It concludes that the spindly slot shape with two narrow ends and one large width at the center is a new valid design. The stress concentration in the squirrel-cage elastic supports can be effectively reduced without increasing the structural weight or changing the structural rigidity. In fact, the parametrical mapping method is a universal approach that combines perfectly the philosophies of computational geometry and shape optimization and it can be thus applied to shape design optimization of holes on other types of surfaces.

Calibrating mix models for NIF tuning

Mixing may play a role in early "tuning" implosions at the National Ignition Facility (NIF), intended for optimizing target geometry and laser operating parameters prior to the first ignition shots. Turbulent transport models allow mixing to be represented in integrated capsule-plus-hohlraum simulations, so that its effects can be predicted. Such models typically have many adjustable coefficients, so it is important to calibrate the coefficients systematically, whether by comparison to experiments, theory, or detailed higher fidelity simulations. We have begun by comparing to results from high-resolution 2D multimode simulations of a NIF Rev3 CH(Ge) ignition capsule, using the time-varying angle-averaged radial profiles of ion species composition as the calibration reference. 1D implosion simulations are performed with either of two turbulence models, and the models are calibrated so that the 1D composition profiles roughly match the 2D reference profiles at a sequence of five times near the end of the implosion. Details of the reference profiles, however, such as non-monotonicity resulting from structures in the flow, cannot be represented by these models. Parameter searches, besides identifying optimal sets of model coefficients, also exhibit model sensitivity to parameter variations.

An MM/3D-RISM Approach for Ligand Binding Affinities

We have modified the popular MM/PBSA or MM/GBSA approaches (molecular mechanics for a biomolecule, combined with a Poisson-Boltzmann or generalized Born electrostatic and surface area nonelectrostatic solvation energy) by employing instead the statistical-mechanical, three-dimensional molecular theory of solvation (also known as 3D reference interaction site model, or 3D-RISM-KH) coupled with molecular mechanics or molecular dynamics ( Blinov , N. ; et al. Biophys. J. 2010 ; Luchko , T. ; et al. J. Chem. Theory Comput. 2010 ). Unlike the PBSA or GBSA semiempirical approaches, the 3D-RISM-KH theory yields a full molecular picture of the solvation structure and thermodynamics from the first principles, with proper account of chemical specificities of both solvent and biomolecules, such as hydrogen bonding, hydrophobic interactions, salt bridges, etc. We test the method on the binding of seven biotin analogues to avidin in aqueous solution and show it to work well in predicting the ligand-binding affinities. We have compared the results of 3D-RISM-KH with four different generalized Born and two Poisson-Boltzmann methods. They give absolute binding energies that differ by up to 208 kJ/mol and mean absolute deviations in the relative affinities of 10-43 kJ/mol.

SU‐GG‐J‐63: Evaluation of Treatment Shifts for Prostate and Rectum Patients Undergoing CBCT Guided IGRT Using KV CBCT

Purpose: We present results of a pilot study established to investigate protocol to access inter‐fraction setup errors for patients with rectal and prostate cancer receiving CBCT based IGRT. We also report on radiation skin doses to patients from a typical CBCT acquisition for daily patient positioning using previously established 2D reference radiochromic film dosimetry protocol. Method and Materials: Patients receiving radical course of IGRT based treatment using CBCT were eligible. Pre‐treatment 3D imaging of 20 patients in treatment position was acquired using kV CBCT on‐board imaging (OBI) system (v. 1.4, Varian Medical Systems, Palo Alto). Scans were preformed using Pelvis CBCT protocol. Reconstructed CBCT images obtained prior to treatment were co‐registered with planning CT data set using bony landmarks for rectal cancer patients and prostate soft tissue visibility and prostate contours for prostate cancer patients. For dose measurements we used 2D dosimetry protocol that employs XR‐QA radiochromic film. Results: Our measurements show that average displacements over investigated rectal cancer patient population was 3.68±1.51 mm in vertical, 3.18±2.0 mm in lateral and 1.59±1.34 mm in longitudinal direction with the maximum observed shift in lateral direction of 11 mm. Average displacements over prostate cancer population showed 2.29±1.69 mm in lateral, 3.36±2.06 mm in vertical, and 3.36±2.06 mm in longitudinal direction with the maximum shift observed in vertical direction of 18 mm. Measured anterior dose during CBCT amounts to 1.60 cGy in larger and up to 3.17 cGy in smaller patients, while the lateral dose was ranging from 1.63 cGy in larger and up to 2.68 cGy in smaller patients. Conclusion: Our investigation showed that 3D conformai therapy with reduced margin in all 3 directions can be used for prostate and rectal cancer patients undergoing daily CBCT based IGRT. However, this benefit must be weighted against dose delivered to patients during CBCT.

SU-DD-A4-04: Comparison of Dose Deposition from KV X-Rays during CBCT Scans between Two Commercially Available On-Line Imaging Systems

Purpose: Accurate dosimetry of the additional dose from kV cone‐beam CT(CBCT)image‐guidedradiation therapy(IGRT) is becoming increasingly important for radiationoncologists to make decisions on IGRT frequency in regards to the additional dose to radiosensitive organs, especially skin. In this study, the skindoses and dose profiles during CBCT scans within an anthropomorphic Rando Phantom were compared for two commercially available systems: X‐ray Volumetric Imager (XVI, Elekta Oncology Systems, Crawley, UK) and On‐Board Imager (OBI, Varian Medical Systems, Palo Alto, CA). Method and Materials:CBCT scans were acquired using the XVI (v. 4.2) on an Elekta Synergy linac (Elekta, Crawley, UK). Doses from three clinical scan protocols Head and Neck S20F0, Chest M20F1, and Prostate M10F1 were compared to doses from similar protocols on OBI (v. 1.4) system using the same 2D reference dosimetry protocol that employs XR‐QA GAFCHROMIC™ film. Results: Our results show that the skindose of 4.5 ± 0.2 cGy from the Prostate M10F1 protocol on XVI, compared to 3.7 ± 0.09 cGy from Pelvis protocol on the OBI system, has higher values. Measured skindose from XVI Head and Neck S20F0 protocol ranged from 0.44 ± 0.01 mGy to 1.58 ± 0.03 mGy, which is significantly lower than the dose from OBI Standard and High Quality head protocols. Dose profiles for the three XVI protocols are heavily dependant on gantry angle sweep during the CBCT acquisition.Conclusions: The skindose from the XVI system is higher for the pelvis and thorax, but is much lower for the head CBCT scans compared to OBI protocols. Given the ability to manipulate the preset parameters, lower doses may be achieved with the XVI system by lowering the total mAs for a given scan, while taking into consideration the image quality reduction.

Visual spatial learning of complex object morphologies through the interaction with virtual and real-world data

Conceptual design relies on extensive manipulation of the morphological properties of real or virtual objects. This study aims to investigate the nature of the perceptual information that could be retrieved in different representation modalities to learn a complex structure. An abstract and complex object was presented to two study populations, experts and non-experts, in three different representation modalities: 2D view; digital 3D model; real object. After viewing, observers had to draw some parts of the structure into a 2D reference frame. The results reveal a considerable performance advantage of digital 3D compared with real 3D, especially in the expert population. The results are discussed in terms of the nature of the morphological cues made available in the different representation modalities.

Average shape standard atlas for the adult Drosophila ventral nerve cord

Neuroanatomy benefits from quantification of neural structures, i.e., neurons, circuits, and brain parts, within a common reference system. Recent improvements in imaging techniques and increased computational power have made the creation of Web-based databases possible, which serve as common platforms for incorporating anatomical data. This study establishes a standard average shape atlas for the ventral nerve cord (VNC) of Drosophila melanogaster. This atlas allows for the registration of morphological, developmental, and genetic data into one quantitative 3D reference system. The standard is based on an average adult Drosophila VNC neuropil as labeled in 24 whole-mount preparations with the commercially available antibody (nc82) recognizing the Drosophila Bruchpilot protein (Brp). For the standardization procedure no expert knowledge of brain anatomy is required and global thresholding as well as straightforward affine and elastic registration procedures minimize user interactions. Successful registration is demonstrated for tracts and commissures, gene expression patterns, and geometric reconstructions of individual neurons. Any structure that is counterstained with anti-Brp can be registered into the standard, allowing for fast comparison of data from different experiments and different laboratories. In addition, standard transformations can be applied to gray scale image data, so that any confocal image stack that is colabeled with anti-Brp can be analyzed within standardized 3D reference coordinates. This allows for the creation of putative neural connectivity maps and the comparison of expression patterns derived from different preparations. The standard and protocols for histological methods, segmentation, and registration procedures will be made available on the Web.

A novel method for error verification of a handy laser scanner

This paper proposes a new method for error verification of a handy laser scanner (HLS), which integrates the calibration model, calibration plate and calibration procedures. The calibration model better describes an accurate modeling of the optical geometry of the HLS. The calibration plate provides a sufficient number of accurate 3D reference points uniformly distributed in a common world coordinate system. And the calibration procedures verify the HLS simultaneously based on the same reference points to eliminate the influences of the HLS calibration error. The influence of the lens distortion of the HLS is also studied, which makes the calibration model give a more accurate mathematical representation of the HLS and thus improves the system measurement accuracy. The experimental results have demonstrated that using this technique to verify the HLS, the measuring accuracy of the HLS can be improved by 36%, which also allows the HLS to automatically position itself in space and generate high-quality measurement in real time.

Theoretical Study on the Scanning Probe Microscopy for Surfaces and Interfaces

Theory and theoretical simulation methods of Scanning Probe Microscopy including Scanning Tunneling Microscopy, and various kinds of Atomic Force Microscopy are reviewed with recent results. The topics introduced here are the method for the STM Simulation, effect of the dissipation on the tunneling current as well as the method for the theoretical simulation of the Atomic Force Microscopy in water. We presented two methods based on the classical molecular dynamics and 3D Reference Interaction Site Method (3D-RISM). Some remarkable properties of the 3D force map of mica in water and the effect of the local charging of the sample on the water mediated force are discussed.