Development of a voxel phantom of Japanese adult male in upright posture

Sato, Kaoru; Noguchi, Hiroshi; Endo, Akira; Emoto, Yutaka; Koga, Sukehiko; Saitô, Kimiaki

doi:10.1093/rpd/ncm272

Cited by 20 publications

(20 citation statements)

References 6 publications

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“…Saito et al [75] from the Japanese Atomic Energy Research Institute (JAERI) developed an adult male model named Otoko (the first Asian phantom) and an adult female phantom named Onago. More recently, Saito et al has developed the JM, JM2, and JF phantoms which have a refined vertical slice thickness [76][77][78]. These phantoms were used mainly for radiation dosimetry applications in Japan.…”

Section: Second-generation Voxel Phantoms (From Late 1980 To Early 20mentioning

confidence: 99%

Computational Phantoms for Organ Dose Calculations in Radiation Protection and Imaging

2013

The Phantoms of Medical and Health Physics

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Dosimetry for ionizing radiation has to do with the determination of amount and distribution pattern of the energy deposited in a part or parts of the human body from internal or external radiation sources. To protect against occupational exposures, dose limits for radiosensitive organs are recommended by international organizations and are adopted as national regulations. In both diagnostic radiology and nuclear medicine, X-ray photons and gamma rays traverse through body tissues to form images of the anatomy, depositing radiation energy in organs along the pathway via secondary electrons. Accurate radiation dosimetry is essential but also quite challenging for three reasons: (1) there are many diverse exposure scenarios resulting in unique spatial and temporal relationships between the source and human body; (2) an exposure can involve multiple radiation types, each of which is governed by different radiation physics principles, such as photons (X-ray photons, gamma rays, and positrons), electrons, alpha particles, neutrons, and protons; (3) the human body consists of a large number of anatomical structures of diverse shape, composition and density, leading to complex radiation interaction patterns. Since it is inconvenient to place a dosimeter inside the human body, organ dose estimates have been obtained mostly using a physical phantom or a computational phantom that mimics the interior and exterior anatomical features of the human body.Historically, the term phantom was used in most radiological science literature to mean a physical model of the human body. In the radiation protection community, however, the term has also been used to refer to a mathematically defined anatomical model that is distinctly different from a physiologically based model such as that related to respiration or blood flow. In this chapter, the phrases, ''computational phantom'' and ''physical phantom,'' are used to avoid confusion.

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Section: Second-generation Voxel Phantoms (From Late 1980 To Early 20mentioning

confidence: 99%

Computational Phantoms for Organ Dose Calculations in Radiation Protection and Imaging

2013

The Phantoms of Medical and Health Physics

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“…Construction procedures for Japanese voxel phantoms developed at Japan Atomic Energy Agency (JAEA) have been described in detail elsewhere 13,14,18,22) but will be briefly outlined. Grey value thresholds are used to segment tissue regions, such as bone, soft tissues, lungs, adipose, and air with different densities.…”

Section: Segmentation Processes Of Organs and Tissuesmentioning

confidence: 99%

“…However, soft tissues cannot be segmented by a single grey value threshold, because there are no significant differences between densities of most soft tissues. Therefore, image processing techniques [2][3][4]13,14,18,22) are used to segment soft tissues. After segmentations, region-specific identification numbers are assigned to voxels belonging to each organ region in order to identify the segmented regions.…”

Section: Segmentation Processes Of Organs and Tissuesmentioning

confidence: 99%

“…The mass fractions of hard bone and bone marrow in voxels of the bone tissue were quantified using the previous segmentation techniques. [2][3][4]13,14,18,22) The mass of bone marrow of JF was adjusted to the average 21) of Japanese adult female. Thus, voxels with grey values below 800 were regarded as bone marrow only, voxels with grey values between 800 and 2040 were regarded as a mixture of bone marrow and hard bone, and voxels with grey values higher than 2040 were regarded as hard bone only.…”

Section: Segmentation Processes Of Organs and Tissuesmentioning

confidence: 99%

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Development of a Japanese Adult Female Voxel Phantom

Sato

Noguchi

Emoto

et al. 2009

Journal of Nuclear Science and Technology

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A Japanese adult female voxel (volume pixel) phantom (JF) was developed using CT images of a healthy female volunteer. The height (152 cm) and weight (44 kg) of JF are smaller than the averages of Japanese adult female. The voxel size of JF is 0:98 Â 0:98 Â 1 mm 3 . Therefore, the shapes of small or complicated organs, such as thyroid and stomach, are distinctly reproduced. The shapes of female-specific organs, such as ovary and uterus, in JF are also realistically represented compared with those of a previously developed phantom. These results suggest that JF enables the accurate evaluation of organ doses due to diverse exposures to Japanese adult females. Photon-specific absorbed fractions (SAFs) for liver or stomach as target organs and for kidney as a source organ were calculated using JF and compared with those of other phantoms. It was concluded that the SAFs calculated using JF and other phantoms depend on the organ distances from source to target.

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“…A whole-body CT scan was carried out at Fujita Health University Hospital after the approval of our plans and objectives by the Ethics Committee of Fujita Health University Hospital. 18,22) A helical CT scanner (Aquilion, Toshiba Medical Systems Co. Ltd., Japan) was used to obtain the CT images. The resolution and slice thickness of CT images used for the construction of JF were 512 Â 512 pixels and 1 mm, respectively.…”

Section: Ct Scans For a Volunteermentioning

confidence: 99%