Visible Chinese Human Research Articles

Non-invasive optical monitoring of human lungs: Monte Carlo modeling of photon migration in Visible Chinese Human and an experimental test on a human.

The human lung was quantified and visualized by photon transport in this paper. A Monte Carlo (MC) simulation of voxelized media was used with the visible Chinese human (VCH). This study theoretically explored the feasibility of non-invasive optical detection of pulmonary hemodynamics, and investigated the optimal location of the light source in the lung photon migration and optimized the source-detector distance. The light fluence intensity showed that the photon penetration depth was 6-8.4 mm in the human lung. The optimal distance from the light source to the detector was 2.7-2.9 cm, but the optimal distance of the superior lobe of right lung was 3.3-3.5 cm. We then conducted experiments on diffuse light reflectance using NIRS on 14 volunteers. These measurements agree well with the simulation results. All the results demonstrated the great potential of non-invasive monitoring of pulmonary hemodynamics and contribute to the study of human lungs in the biomedical optics community.

Optimize Illumination Parameter of Low-Level Laser Therapy for Hemorrhagic Stroke by Monte Carlo Simulation on Visible Human Dataset

Stroke is the second leading cause of death and disability worldwide. The incidence of hemorrhagic stroke increases dramatically with the increasingly aging population. Recently, technology of low-level light/laser therapy (LLLT) is emerging as a novel noninvasive therapeutic approach to treat stroke based on effective photobiomodulation. To obtain optimal therapeutic effects, several LLLT illumination parameters such as beam size and beam type need to be optimized. However, the quantitative optimization of LLLT illumination parameters for stroke therapeutics is impractical to test directly on human subjects. In this paper, we employed a precise voxelized three-dimensional Monte Carlo method (MCVM) to simulate photon propagation within Visible Chinese human (VCH) head at different level of stroke with varied parameters of beams. By evaluation with criteria of the total fluence flux in lesion region and the maximal penetration depth, we found that Gaussian beam with larger or the same size of hemorrhagic region generates the highest and relative homogeneous therapeutic outcomes, while the Top-hat beam performed better when hemorrhagic region is much bigger than beam size. These results demonstrate the great potential of using VCH and MCVM in optimizing LLLT treatment parameters for stroke and in guiding future instrumentation of LLLT on hemorrhagic stroke.

Virtual Laparoscopic Training System Based on VCH Model.

Laparoscopy has been widely used to perform abdominal surgeries, as it is advantageous in that the patients experience lower post-surgical trauma, shorter convalescence, and less pain as compared to traditional surgery. Laparoscopic surgeries require precision; therefore, it is imperative to train surgeons to reduce the risk of operation. Laparoscopic simulators offer a highly realistic surgical environment by using virtual reality technology, and it can improve the training efficiency of laparoscopic surgery. This paper presents a virtual Laparoscopic surgery system. The proposed system utilizes the Visible Chinese Human (VCH) to construct the virtual models and simulates real-time deformation with both improved special mass-spring model and morph target animation. Meanwhile, an external device that integrates two five-degrees-of-freedom (5-DOF) manipulators was designed and made to interact with the virtual system. In addition, the proposed system provides a modular tool based on Unity3D to define the functions and features of instruments and organs, which could help users to build surgical training scenarios quickly. The proposed virtual laparoscopic training system offers two kinds of training mode, skills training and surgery training. In the skills training mode, the surgeons are mainly trained for basic operations, such as laparoscopic camera, needle, grasp, electric coagulation, and suturing. In the surgery-training mode, the surgeons can practice cholecystectomy and removal of hepatic cysts by guided or non-guided teaching.

Effect of head model on Monte Carlo modeling of spatial sensitivity distribution for functional near-infrared spectroscopy

Modeling Light propagation within human head to deduce spatial sensitivity distribution (SSD) is important for Near-infrared spectroscopy (NIRS)/imaging (NIRI) and diffuse correlation tomography. Lots of head models have been used on this issue, including layered head model, artificial simplified head model, MRI slices described head model, and visible human head model. Hereinto, visible Chinese human (VCH) head model is considered to be a most faithful presentation of anatomical structure, and has been highlighted to be employed in modeling light propagation. However, it is not practical for all researchers to use VCH head models and actually increasing number of people are using magnet resonance imaging (MRI) head models. Here, all the above head models were simulated and compared, and we focused on the effect of using different head models on predictions of SSD. Our results were in line with the previous reports on the effect of cerebral cortex folding geometry. Moreover, the influence on SSD increases with the fidelity of head models. And surprisingly, the SSD percentages in scalp and gray matter (region of interest) in MRI head model were found to be 80% and 125% higher than in VCH head model. MRI head models induced nonignorable discrepancy in SSD estimation when compared with VCH head model. This study, as we believe, is the first to focus on comparison among full serials of head model on estimating SSD, and provided quantitative evidence for MRI head model users to calibrate their SSD estimation.

Organ dose conversion coefficients for external neutron irradiation based on the Chinese mathematical phantom (CMP)

A group of Monte Carlo simulations has been performed for external neutron dosimetry calculation based on a whole-body mathematical model. The Chinese mathematical phantom (CMP) is a mathematical human body model developed based on methods of ORNL (Oak ridge National Laboratory) mathematical phantom series (OMPS), and data from Chinese reference man and reference Asian man. Fluence-to-absorbed dose conversion coefficients of 24 organs and tissues for monoenergetic neutron beams ranging from 10−9 to 102 MeV were calculated using the Monte Carlo code MCNPX. Irradiation conditions include anterior–posterior, posterior–anterior, right lateral, left lateral, rotational, and isotropic geometries. Results for the different organs are compared with those recommended in International Commission of Radiological Protection (ICRP) publication 74 and results obtained based on the visible Chinese human (VCH) phantom. Overall the consistency among the three sets of data was observed, but significant deviations up to 30–50% were also found in the AP, PA and lateral irradiation conditions. Since CMP represents the Chinese population, this work is helpful as a reference to investigate the difference of the neutron induced organ doses due to the anatomical variation between the Chinese and the Caucasians, and that between the average population and an individual.

THE DEVELOPMENT AND APPLICATION OF THE VISIBLE CHINESE HUMAN MODEL FOR MONTE CARLO DOSE CALCULATIONS

A new whole-body computational phantom, the Visible Chinese Human (VCH), was developed using high-resolution transversal photographs of a Chinese adult male cadaver. Following the segmentation and tridimensional reconstruction, a voxel-based model that faithfully represented the average anatomical characteristics of the Chinese population was established for radiation dosimetry. The vascular system of VCH was fully preserved, and the cadaver specimen was processed in the standing posture. A total of 8,920 slices were obtained by continuous sectioning at 0.2 mm intervals, and 48 organs and tissues were segmented from the tomographic color images at 5440 x 4080 pixel resolution, corresponding to a voxel size of 0.1 x 0.1 x 0.2 mm3. The resulting VCH computational phantom, consisting of 230 x 120 x 892 voxels with a unit volume of 2 x 2 x 2 mm3, was ported into Monte Carlo code MCNPX2.5 to calculate the conversion coefficients from kerma free-in-air to absorbed dose and to effective dose for external monoenergetic photon beams from 15 keV to 10 MeV under six idealized external irradiation geometries (anterior-posterior, posterior-anterior, left lateral, right lateral, rotational, and isotropic). Organ masses of the VCH model are fairly different from other human phantoms. Differences of up to 300% are observed between doses from ICRP 74 data and those of VIP-Man. Detailed information from the VCH model is able to improve the radiological datasets, particular for the Chinese population, and provide insights into the research of various computational phantoms.

Monte Carlo simulations for external neutron dosimetry based on the visible Chinese human phantom

A group of Monte Carlo simulations has been performed for external neutron dosimetry calculation based on a whole-body anatomical model, the visible Chinese human (VCH) phantom, which was newly developed from high-resolution cryosectional color photographic images of a healthy Chinese adult male cadaver. Physical characteristics of the VCH computational phantom that consists of 230 × 120 × 892 voxels corresponding to an element volume of 2 × 2 × 2 mm3 are evaluated through comparison against a variety of other anthropomorphic models. Organ-absorbed doses and the effective doses for monoenergic neutron beams ranging from 10−9 MeV to 10 GeV under six idealized irradiation geometries (AP, PA, LLAT, RLAT, ROT and ISO) were calculated using the Monte Carlo code MCNPX2.5. Absorbed dose results for selected organs and the effective doses are presented in the form of tables. Dose results are also compared with currently available neutron data form ICRP Publication 74 and those of VIP-Man. Anatomical variations between different models, as well as their influence on dose distributions, are explored. Detailed information derived from the VCH phantom is able to lend quantitative references to the widespread application of human computational models in radiology.

Virtual Temporal Bone Anatomy

The Visible Human Project (VHP) initiated by the U.S. National Library of Medicine has drawn much attention and interests from around the world. The Visible Chinese Human (VCH) project has started in China. The current study aims at acquiring a feasible virtual methodology for reconstructing the temporal bone of the Chinese population, which may provide an accurate 3-D model of important temporal bone structures that can be used in teaching and patient care for medical scientists and clinicians. A series of sectional images of the temporal bone were generated from section slices of a female cadaver head. On each sectional image, SOIs(structures of interest) were segmented by carefully defining their contours and filling their areas with certain gray scale values. The processed volume data were then inducted into the 3D Slicer software (developed by the Surgical Planning Lab at Brigham and Women's Hospital and the MIT AI Lab) for resegmentation and generation of a set of tagged images of the SOIs. 3D surface models of SOIs were then reconstructed from these images. The temporal bone and structures in the temporal bone, including the tympanic cavity, mastoid cells, sigmoid sinus and internal carotid artery, were successfully reconstructed. The orientation of and spatial relationship among these structures were easily visualized in the reconstructed surface models. The 3D Slicer software can be used for 3-dimensional visualization of anatomic structures in the temporal bone, which will greatly facilitate the advance of knowledge and techniques critical for studying and treating disorders involving the temporal bone.