Development and anatomical details of Japanese adult male/female voxel models Tomoaki Nagaoka, Soichi Watanabe, *Etsuo kunieda, **Masao Taki and Yukio Yamanaka National Institute of Information and Communications Technology * Department of Radiology School of Medicine, Keio University ** Department of Electrical Engineering, Tokyo Metropolitan University CONTENTS 1. Development and details of voxel models 2. Variable model (recent studies) Objectives Today, modern medical imaging and computer technologies allow development of new realistic (anatomical) whole-body models Develop realistic whole-body models ・Average Japanese (Asian) body shape ・Adult male and female ・Applicable to high-frequency EM fields (over 1 GHz) Procedures for Developing the Voxel Models Step1 : Acquisition of Subject’s Whole-body MRI Data (Axial Images) Cast Head Body MRI : Signa Advantage Lx 1.5T Scan parameters Pulse Sequence TR (ms) TE (ms) NSA Thickness (mm) Matrix FOV (mm) Head SE 500 16 3 2 256×256 240 Body SE 1000 9 1 2 256×256 480 Original Images for Numerical Models Male 22 Y 173.2 cm 65 kg Voxel size 2×2×2mm Female 22 Y 160.4 cm 53 kg Voxel size 2×2×2mm Step4: Identification of Tissue/Organ Types Tissue/organ identification list (extract) ID Tissue/organ Ｒ Ｇ Ｂ ID Tissue/organ Ｒ Ｇ Ｂ １ Skin ２５５ ０ ３ Gray matter ０ Muscle ２５５ ０ ４ White matter １７ ３ １２ ８ ２５ ５ ０ ２ ２５ ５ ０ Example of identification for transverse images Original Image Tissue-identified Image ４７ Step5: Final Correction Using 3D Images Smoothing of tissue/organ boundaries Checking the three orthogonal planes(axial,sagittal and coronal) Before Supervision by medical doctors After Details of Present Models 3-D Display of Present Models Voxel size: 2x2x2 mm Tissues and organs : 51 different types Ｍａｌ ｅ Ｆｅｍａ ｌｅ Mid-coronal Ｍａ ｌｅ Ｆｅｍ ａｌｅ Mid-sagittal Ｍａｌｅ Ｆｅｍａ ｌｅ Bone enhancement Body Dimensions (Comparison with average Japanese) Mean deviation of total measurement items Male, 4.03 ％ ; Female, 3.28 ％ Male H eight H ead length 1 .1 6 Tibiale height 1 .0 8 H ead breadth 1 .0 0 S ym physion height 0 .9 2 0 .8 4 Totalhead height C hest breadth A bdom inaldepth Trunk length B ideltoid breadth B icristalbreadth Female Masses of tissues/organs （Comparison with average Japanese) Deviation of mass of tissue or organ < 30% Male, about 60% ; Female, ：about 80 % Brain Skin Muscle Fat Skeleton 1.6 1.3 1 0.7 0.4 0.1 Male Salivary gland Large intestine Heart Kidney Thyroid Liver Stomach Pancreas Spleen Small intestine Female Summary of whole-body voxel models of Japanese Realistic high-resolution whole-body voxel models developed using MRI data from a Japanese adult male and female. • Highly precise simulation for Japanese (Asian) subjects • Electromagnetic exposure evaluation at high frequencies (up to 3 GHz) • Applicable to a variety of research fields （Radiation dosimetry, elastic analysis and thermal analysis） Future Plans • More suitable for masses of the tissues and organs of an average Japanese • Addition of tissues and organs (Yellow and red marrow, etc) Free sharing of database of developed voxel models Web site http://www2.nict.go.jp/mt/b186/bio/bio_human_model_E.html Recent studies about voxel models Variable model • Posture • Voxel-dimension • Age (figure) Pregnant woman model Development of variable posture model Posture transformation Free Form Deformation ① Object ② Control Cell ③ ④ ●：Control point Posture transformation of developed model using FFD Example of flexion (arm) 0 degrees 45 degrees 90 degrees Example of variable posture model Development of variable voxel-dimension models Example of rescale Size:2 mm Size: 1 mm Voxel sizel : 2 mm Smoothing ( The corner part is smooth) Voxel sizel : 1 mm Development of variable age (figure) models Figure’s transformation Child voxel model Adult voxel model Whole-body figures of Children Figure 1 Figure 2 About 3 years old 90cm, 13kg About 5 years old 105cm, 17kg Figure 3 About 7 years old 120cm, 23kg Body-dimension measurements of child Total of measurement items = 66 Average figures of child Surface model 3 years old 5 years old 7 years old Figure’s transformation (FFD algorithm) Child voxel models Development of pregnant woman model Body-dimension measurements of pregnant woman Subjects ( 5 volunteers) ・ Height: about 156-160cm ・ Progestational weight:50-52 kg ・ Age: 20-39 years old (Japanese woman) ・ After 7 month pregnant Total of measurement items = 104 ( 66 items : same items as child, 37 items: only pregnant woman) Surface model of pregnant woman 10 month MR Image of fetus Future prospects FFD and/or morphing Summary and future plans of variable models and pregnant woman model • Introduction of the variable models and pregnant woman model as the results of our present studies • The functions of these voxel models are based on adult voxel models We are continuing to improve the models and functions.
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