• Title/Summary/Keyword: applicator

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Dose Distribution of 3-Channel Ovoid Applicator (3-Channel Vaginal Ovoids의 선량분포 특성)

  • Kim Chang Hee;Yun Sang Mo;Kim Sung Kyu;Shin Sei One
    • Progress in Medical Physics
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    • v.15 no.3
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    • pp.134-139
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    • 2004
  • This study was aimed to develop a new ovoid applicator for vaginal high-dose rate intracavitary radiation therapy, evaluate uniformity of dose distribution, and assess clinical applicability. The authors evaluated dose uniformity of vaginal mucosa according to 5-different ovoid-separation using 2-channel and modified 3-channel ovoid applicator. There were no significant differences in the dose distribution along the vaginal mucosa with 2 and 2.5 cm separations, but there were between the 2-channel and 3-channel ovoid applicator with a separation of 3 cm or more. Although a low dose area was shown between two ovoid applicators with the 2-channel ovoid applicator, the dose distribution along the vaginal mucosa with the 3-channel ovoid applicator was very uniform.

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Design of a New Applicator for High-Dose Rate Vaginal Brachytherapy (고선량율 질강 근접조사를 위한 새로운 적용구의 제작)

  • Shin, Sei One
    • Yeungnam University Journal of Medicine
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    • v.17 no.2
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    • pp.123-128
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    • 2000
  • Purpose: This study was aimed to develop a new vaginal applicator(Shin's Applicator) for 2-channel high-dose rate vaginal brachytherapy to evaluate uniformity of surface dose, and to present 3-dimensional dose distribution of the applicator. Methods: Shin's Applicator was inexpensively constructed using human soft tissue equivalent acrylic bar. We evaluated dose uniformity along the applicator surface using film densitometer and performed vaginal intracavitary brachytherapy after insertion of the applicator using HDR brachytherapy planning software and brachytherapy unit(Ralstron-20B). Results: Shin's Applicator allows improved dose distribution than the existing 1-channel cylinder and achieves diminished urinary bladder and rectal dose by 20%. Conclusions: From the above results, it can be concluded that Shin's Applicator may be an improved form of a vaginal applicator. Furthermore, it can be suggested that this applicator has an advantage, for it prevents vaginal stenosis after radiation therapy and can be used as a disposable vaginal dilator. Further follow up examination with radiological study may be helpful to evaluate the therapeutic efficacy of this applicator.

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Development of Variable Rate Granule Applicator for Environment-Friendly Precision Agriculture (I) - Concept Design of Variable Rate Pneumatic Granule Applicator and Manufacture of Prototype - (친환경 정밀농업을 위한 입제 변량살포기 개발 (I) - 송풍식 입제 변량살포기 개념설계와 시작기 제작 -)

  • Ryu K.H.;Kim Y.J.;Cho S.I.;Rhee J.Y.
    • Journal of Biosystems Engineering
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    • v.31 no.4
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    • pp.305-314
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    • 2006
  • Precision farming has been known as an environment friendly farming technology. This study was conducted to develop a variable-rate granule fertilizer applicator as an attempt for introducing the precision farming technologies to rice cultivation in Korea. In this paper, concept design process and manufacturing of prototype variable rate granule applicator was reported. For concept design, some design guide lines were selected. Based on the design guide line and some engineering knowledge, concept design was conducted. The designed prototype granule applicator was mounted at the rear of riding type cultivator for paddy field and had a 10m wide boom structure with pneumatic conveying and application system as well as 1GPS receiver, 1 granule hopper, 12 blow heads, 2 metering devices and 1 controller. The fertilizer applicator had 942 ka of weight, 740m of ground clearance and 1,117mm of center of gravity from the ground. The applicator was designed to be able to $34{\sim}428kg/ha$ of granule at $0.2{\sim}0.8m/s$ of fertilizer working speed.

Dose Characteristics for IORT Applicator of ML-15MDX Electron Beam (ML-15MDX 술중조사용 Applicator에 의한 전자선선량 특성)

  • Choi, Tae-Jin;Lee, Ho-Joon;Kim, Yeung-Ae;Kim, Jin-Hee;Kim, Ok-Bae
    • Radiation Oncology Journal
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    • v.11 no.2
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    • pp.455-461
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    • 1993
  • Experimental measurements of dose characteristics with pentagonal applicator at nominal energy of 4, 6, 9, 12 and 15 MeV electron beam were performed for intraoperative radiotherapy (IORT) in ML-15MDX linear accelerator. This paper presents the percent depth dose, surface dose, beam flatness and output factors of using the IORT applicator in different electron beam energy. The output factor showed as a 24 percent higher in IORT applicator than that of reference $10{\times}10cm^2$ applicator. The surface dose of using the IORT applicator showed 7.7 and 2.7 percent higher than that of reference field in 4 and 15 MeV electron beam, respectively. In our experiments, the variation of percent depth dose was very small but the output factor and flatnees at 0.5 cm depth have showed a large value in IORT applicator.

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The Improvement of Characteristics of The Applicator Using Semi-rigid Coaxial Cable Antenna for RFA (반강체 동축케이블 안테나를 이용한 RFA용 어플리케이터의 특성 개선)

  • 강철준;박성교;김선호;박종백
    • Proceedings of the IEEK Conference
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    • pp.24-27
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    • 2003
  • Radiofrequency ablation (RFA) as one of the microwave hyperthermia is becoming the treatment of choice for small but inoperable tumors of the liver. In this paper, we designed the applicator composed of semi-rigid coaxial cable antenna with a ring slot for RFA. To optimize the maximum output of radiation with omni direction at 2450 ㎒, we simulated the applicator using Electromagnetic simulation program and analyzed the return loss and the electric field E$\_$tot/ at the near-field region between the simulation results and measurement results. As a result, we obtained the return loss of -29.786 dB at 2450 ㎒ when the applicator was placed between two blocks of a pig's liver, and the measurement results agreed with the simulation results well. Therefore, this applicator using semi-rigid coaxial cable antenna with a ring slot can be used very usefully as the applicator for RFA.

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Utrecht Interstitial Applicator Shifts and DVH Parameter Changes in 3D CT-based HDR Brachytherapy of Cervical Cancer

  • Shi, Dan;He, Ming-Yuan;Zhao, Zhi-Peng;Wu, Ning;Zhao, Hong-Fu;Xu, Zhi-Jian;Cheng, Guang-Hui
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.9
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    • pp.3945-3949
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    • 2015
  • Background: For brachytherapy of cervical cancer, applicator shifts can not be avoided. The present investigation concerned Utrecht interstitial applicator shifts and their effects on organ movement and DVH parameters during 3D CT-based HDR brachytherapy of cervical cancer. Materials and Methods: After the applicator being implanted, CT imaging was achieved for oncologist contouring CTVhr, CTVir, and OAR, including bladder, rectum, sigmoid colon and small intestines. After the treatment, CT imaging was repeated to determine applicator shifts and OARs movements. Two CT images were matched by pelvic structures. In both imaging results, we defined the tandem by the tip and the base as the marker point, and evaluated applicator shift, including X, Y and Z. Based on the repeated CT imaging, oncologist contoured the target volume and OARs again. We combined the treatment plan with the repeated CT imaging and evaluated the change range for the doses of CTVhr D90, D2cc of OARs. Results: The average applicator shift was -0.16 mm to 0.10 mm for X, 1.49 mm to 2.14 mm for Y, and 1.9 mm to 2.3 mm for Z. The change of average physical doses and EQD2 values in Gy${\alpha}/{\beta}$ range for CTVhr D90 decreased by 2.55 % and 3.5 %, bladder D2cc decreased by 5.94 % and 8.77 %, rectum D2cc decreased by 2.94 % and 4 %, sigmoid colon D2cc decreased by 3.38 % and 3.72 %, and small intestines D2cc increased by 3.72 % and 10.94 %. Conclusions: Applicator shifts and DVH parameter changes induced the total dose inaccurately and could not be ignored. The doses of target volume and OARs varied inevitably.

Circularly Rotated Array for Dual Polarized Applicator in Superficial Hyperthermia System

  • Kim, Ki Joon;Choi, Woo Cheol;Yoon, Young Joong
    • Journal of electromagnetic engineering and science
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    • v.15 no.1
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    • pp.20-25
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    • 2015
  • A circularly rotated array for a dual polarized applicator in a superficial hyperthermia system is proposed. The applicator has a wider effective treatment area due to the $180^{\circ}$ phase shift. The dual polarized circularly rotated array (DPCRA) suppresses overheating at the center of the array and helps evenly distribute the heat. This array provides a more effective treatment area than a lattice array when a $2{\times}2$ dual polarized array is fitted to the treatment area. The treatment area is 71.5% of the aperture, whereas the effective treatment areas of the $2{\times}2$ dual polarized lattice array (DPLA) and the single polarized array (SPA) are 57.2% and 38.6% of the same aperture, respectively. The measurement matches the simulation results without blood circulation effects. In a $2{\times}2$ array applicator, the proposed DPCRA has more heat uniformity than the DLA and the SPA.

A study on Development of a Pneumatic Granular Applicator for Paddy Field (I) - Granular Discharge Rate, Diffuser and Optimal Application Conditions - (수도작용 송풍식 입제살포기 재발에 관한 연구 (I) - 입제 배출량, 분두 및 적정살포조건 -)

  • 정창주;정선옥;장영창;최영수;최중섭
    • Journal of Biosystems Engineering
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    • v.22 no.2
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    • pp.127-136
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    • 1997
  • This study was accomplished to develop a pneumatic granular applicator that can be attached to the conventional ride-on rice transplanter. Operating conditions of a metering device for the applicator were determined so as to obtain the required discharge rate of granules for field application. The shape and size of diffuser was selected for the applicator and the spacing between diffusers on a boom and the boom height were determined as an optimal application condition for uniform distribution. The diffuser spacing of 1m for the fertilizer and the diffuser spacing of 0.8m for the pesticide at the boom height over 0.8m were acceptable.

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Adaptability Analysis of Granule Fertilizer Applicator for Rapeseed Broadcasting (입제 비료살포기의 유채 파종 적용성 분석)

  • Lee, C.K.;Choi, Y.;Jun, H.J.;Lee, C.S.;Kim, Y.J.;Lee, S.K.;Oh, S.H.
    • Journal of Biosystems Engineering
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    • v.34 no.2
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    • pp.106-113
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    • 2009
  • This study was carried out to test feasibility of a granule fertilizer applicator for rapeseed seeding in paddy fields. The metering plate of a conventional applicator was modified for rapeseed seeding. The modified plate had new three seeding openings with total area of $342mm^2$. Average target discharging rates ranged from 6.3 to 21.0 g/s and correlated with opening areas. Application patterns of the rapeseed seeding showed M-shape. The coefficients of variation of the application showed 70.5% at 0.99 m/s of forwarding speed and 14.3 g/s of a discharge rate, and 77.7% at 1.72 m/s of a forwarding speed and 8.23 g/s of a discharge rate. The coefficients of variation in the direction of transverse of the tractor ranged from 7.3 to 47.7%. In rapeseed seeding tests using the applicator, seed damages rates were less than 15% due to the agitator, the seed hopper and the seeding plate break. Therefore, improvements of the applicator blow heads and seeding equipments were required in order to apply rapeseed efficiently.