• Progress in Medical Physics
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• v.24 no.1
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• pp.35-40
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• 2013

Recently, the uses of Multi-Detector Computed Tomography (MDCT) for radiation treatment simulation and planning which is used for intensity modulated radiation therapy with high technique are increasing. Because of the increasing uses of MDCT, additional doses are also increasing. The objective of this study is to evaluate the absorbed dose of body and skin undergoing in MDCT scans. In this study, the exposed dose at the surface and the center of the cylindrical water phantom was measured using an pencil ionization chamber, 30 cc ionization chamber and TL Powder. The results of MDCT were 31.84 mGy, 33.58 mGy and 32.73 mGy respectively. The absorbed dose at the surface showed that the TL reading value was 33.92 mGy from MDCT. These results showed that the surface dose was about 3.5% from the MDCT exposure higher than a dose which is located at the center of the phantom. These results mean that the total exposed dose undergoing MDCT 4 times (diagnostic, radiation therapy planning, follow-up et al.), is about 14 cGy, and have to be considered significantly to reduce the exposed dose from CT scan.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.528-553
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• 2020

Upland fields are characterized by dry environments, a high degree of disturbance by farming practices such as double-cropping, and a high diversity of crops compared to other field types. This study focused on the floristic composition and characteristics of upland fields in South Korea. Flora surveys were conducted in 36 areas in nine provinces at two times (June and August) in 2015. The results showed that the vascular plants in the upland fields in South Korea included 532 taxa, containing 100 families, 322 genera, 483 species, nine subspecies, 37 varieties, one form, and two hybrids. Among the 100 families, Asteraceae was the most diverse in species (75 taxa), followed by Poaceae (68 taxa), Fabaceae (34 taxa), Polygonaceae (21 taxa), Rosaceae (19 taxa), and Liliaceae (17 taxa). Based on the occurrence frequency of each species, Acalypha australis L. (100%), and Artemisia indica Willd. (100%) were the highest, followed by Humulus scandens (Lour.) Merr., Rorippa palustris (L.) Besser, Conyza canadensis (L.) Cronquist, Erigeron annuus (L.) Pers., Lactuca indica L., Commelina communis L., Digitaria ciliaris (Retz.) Koeler, Echinochloa crus-galli(L.) P.Beauv., Cyperus microiria Steud., and Oxalis corniculata L. The biological type of upland fields in South Korea was determined to be Th-R₅-D₄-e type. Rare plants were found in 11 taxa: Taxus cuspidata Siebold & Zucc, Magnolia kobus DC, Clematis trichotoma Nakai, Aristolochina contorta Bunge, Buxus sinica (Rehder & E.H.Wilson) M.Cheng var. koreana (Nakai ex Rehder) Q.L.Wang, Melothria japonica (Thunb.) Maxim, Mitrasacme indica Wight, Lithospermum arvense L., Carpesium rosulatum Miq., Allium senescens L., and Pseudoraphis sordida (Thwaites) S.M.Phillips & S.L.Chen. Ninety-seven taxa contained naturalized plants composed of 24 families, 68 genera, 97 species, one variety, and one form. The urbanization and naturalization indices were 30.5% and 18.4%, respectively.