Development of the two Korean adult tomographic computational phantoms for organ dosimetry

Abstract

Following the previously developed Korean tomographic phantom, KORMAN, two additional whole-body tomographic phantoms of Korean adult males were developed from magnetic resonance (MR) and computed tomography (CT) images, respectively. Two healthy male volunteers, whose body dimensions were fairly representative of the average Korean adult male, were recruited and scanned for phantom development. Contiguous whole body MR images were obtained from one subject exclusive of the arms, while whole-body CT images were acquired from the second individual. A total of 29 organs and tissues and 19 skeletal sites were segmented via image manipulation techniques such as gray-level thresholding, region growing, and manual drawing, in which each of segmented image slice was subsequently reviewed by an experienced radiologist for anatomical accuracy. The resulting phantoms, the MR-based KTMAN-1 (Korean Typical MAN-1) and the CT-based KTMAN-2 (Korean Typical MAN-2), consist of 300 X 150 X 344 voxels with a voxel resolution of 2 X 2 X 5 mm3 for both phantoms. Masses of segmented organs and tissues were calculated as the product of a nominal reference density, the prevoxel volume, and the cumulative number of voxels defining each organs or tissue. These organs masses were then compared with those of both the Asian and the ICRP reference adult male. Organ masses within both KTMAN-1 and KTMAN-2 showed differences within 40% of Asian and ICRP reference values, with the exception of the skin, gall bladder, and pancreas which displayed larger differences. The resulting three-dimensional binary file was ported to the Monte Carlo code MCNPX2.4 to calculate organ doses following external irradiation for illustrative purposes. Colon, lung, liver, and stomach absorbed doses, as well as the effective dose, for idealized photon irradiation geometries (anterior-posterior and right lateral) were determined, and then compared with data from two other tomographic phantoms (Asian and Caucasian), and stylized ORNL phantom. The armless KTMAN-1 can be applied to dosimetry for computed tomography or lateral x-ray examination, while the whole body KTMAN-2 can be used for radiation protection dosimetry.

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

“…The reference values for radiation protection provided by the ICRP publication 74 [2] were calculated with mathematical phantoms, which is called 'MIRD-type', where the body and the organs or the tissues are composed of simply geometrical shapes [3,4]. With the quick development of computers and medical imaging techniques, researchers have made considerable efforts to develop voxel-based anatomical models based on computer tomography (CT), magnetic resonance imaging (MRI), or color images of individuals for radiation dosimetry [5][6][7][8][9][10][11][12][13][14]. More than 30 voxel-based models have been established till now [15], a few of which are based on Chinese specimen, such as VCH phantom and CNMAN [16,17].…”

Construction of a High-quality Voxel Model VKH-Man Using Serially Sectioned Images from Visible Korean Human Project in Korea

“…Since then, most voxel models have been constructed using CT and MR images [2][3][4] . In general, CT and MR images provide fairly good information for accurate delineation of organs and tissues, but it is very difficult to distinguish some organs and tissues that share similar properties with neighboring tissues or that are in continuous movement (e.g., ovaries, pancreas, oesophagus, adrenals, thymus, small intestine, heart) [5][6] .…”

“…+82-2-2220-0513; Fax. +82-2-2220-4057;E-mail: chkim@hanyang.ac.kr from other computational models (KTMAN-2, VIP-Man, and ICRP-74) 4,7,10) .…”

A study of the effect of the lung shape on the lung absorbed dose in six standard photon and neutron exposure geometries

“…In addition, researchers developed some Asian reference phantoms based on the Asian Standard Man data (Saito et al, 2001;Lee et al 2004Lee et al , 2006Sato et al, 2007;Zhang et al, 2007;Li et al, 2009). Although the discrepancies between the organ masses and volumes of different Caucasian reference phantoms are fairly small, their mirihakim@ferdowsi.um.ac.ir organ doses in the photon fields differ significantly in some situations Ferrari et al, 2005;Zhang et al, 2009b;Kramer et al, 2010).…”