• Title/Summary/Keyword: Rectum

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Dose Distribution of Intensity Modulated Radiation Therapy in Prostate Cancer (전립선암에서 세기조절방사선치료의 선량분포 특성)

  • Kim, Sung-Kyu;Choi, Ji-Hoon;Yun, Sang-Mo
    • Progress in Medical Physics
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    • v.21 no.3
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    • pp.298-303
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    • 2010
  • The aim of this study was to compare the dose distribution of intensity modulated radiation therapy (IMRT) with 3 dimensional conformal radiation therapy (3DCRT) in prostate cancer. The IMRT plan and the 3DCRT plan used the 9 fields technique, respectively. In IMRT, tumor dose was a total dose of 66 Gy at 2.0 Gy per day, 5 days a week for 5 weeks. All cases were following the dose volume histogram (DVH) constraints. The maximum and minimum tumor dose constraints were 6,700 cGy and 6,500 cGy, respectively. The rectum dose constraints were <35% over 50 Gy. The bladder dose constraints were <35% over 40 Gy. The femur head dose constraints were <15% over 20 Gy. Tumor dose in the 3DCRT were 66 Gy. In IMRT, the maximum dose of PTV was 104.4% and minimum dose was 89.5% for given dose. In 3DCRT, the maximum dose of PTV was 105.3% and minimum dose was 85.5% for given dose. The rectum dose was 34.0% over 50 Gy in IMRT compared with 63.3% in 3DCRT. The bladder dose was 30.1% over 40 Gy in IMRT compared with 30.6% in 3DCRT. The right femur head dose was 9.5% over 20 Gy in IMRT compared with 17.5% in 3DCRT. The left femur head dose was 10.6% over 20 Gy in IMRT compared with 18.3% in 3 DCRT. The dose of critical organs (rectum, bladder, and femur head) in IMRT showed to reduce than dose of 3DCRT. The rectum dose over 50 Gy in IMRT was reduced 29.3% than 3DCRT. The bladder dose over 40 Gy in IMRT was similar to 3DCRT. The femur head dose over 20 Gy in IMRT was reduced about 7~8% than 3DCRT.

Inter-fractional Target Displacement in the Prostate Image-Guided Radiotherapy using Cone Beam Computed Tomography (전립선암 영상유도 방사선 치료시 골반내장기의 체적변화에 따른 표적장기의 변화)

  • Dong, Kap Sang;Back, Chang Wook;Jeong, Yun Jeong;Bae, Jae Beom;Choi, Young Eun;Sung, Ki Hoon
    • The Journal of Korean Society for Radiation Therapy
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    • v.28 no.2
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    • pp.161-169
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    • 2016
  • Purpose : To quantify the inter-fractional variation in prostate displacement and their dosimetric effects for prostate cancer treatment. Materials and Methods : A total of 176 daily cone-beam CT (CBCT) sets acquired for 6 prostate cancer patients treated with volumetric-modulated arc therapy (VMAT) were retrospectively reviewed. For each patient, the planning CT (pCT) was registered to each daily CBCT by aligning the bony anatomy. The prostate, rectum, and bladder were delineated on daily CBCT, and the contours of these organs in the pCT were copied to the daily CBCT. The concordance of prostate displacement, deformation, and size variation between pCT and daily CBCT was evaluated using the Dice similarity coefficient (DSC). Results : The mean volume of prostate was 37.2 cm3 in the initial pCT, and the variation was around ${\pm}5%$ during the entire course of treatment for all patients. The mean DSC was 89.9%, ranging from 70% to 100% for prostate displacement. Although the volume change of bladder and rectum per treatment fraction did not show any correlation with the value of DSC (r=-0.084, p=0.268 and r=-0.162, p=0.032, respectively), a decrease in the DSC value was observed with increasing volume change of the bladder and rectum (r=-0.230,p=0.049 and r=-0.240,p=0.020, respectively). Conclusion : Consistency of the volume of the bladder and rectum cannot guarantee the accuracy of the treatment. Our results suggest that patient setup with the registration between the pCT and daily CBCT should be considered aligning soft tissue.

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Convolution-Superposition Based IMRT Plan Study for the PTV Containing the Air Region: A Prostate Cancer Case (Convolution-Superposition 알고리즘을 이용한 치료계획시스템에서 공기가 포함된 표적체적에 대한 IMRT 플랜: 전립선 케이스)

  • Kang, Sei-Kwon;Yoon, Jai-Woong;Park, Soah;Hwang, Taejin;Cheong, Kwang-Ho;Han, Taejin;Kim, Haeyoung;Lee, Me-Yeon;Kim, Kyoung Ju;Bae, Hoonsik
    • Progress in Medical Physics
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    • v.24 no.4
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    • pp.271-277
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    • 2013
  • In prostate IMRT planning, the planning target volume (PTV), extended from a clinical target volume (CTV), often contains an overlap air volume from the rectum, which poses a problem inoptimization and prescription. This study was aimed to establish a planning method for such a case. There can be three options in which volume should be considered the target during optimization process; PTV including the air volume of air density ('airOpt'), PTV including the air volume of density value one, mimicking the tissue material ('density1Opt'), and PTV excluding the air volume ('noAirOpt'). Using 10 MV photon beams, seven field IMRT plans for each target were created with the same parameter condition. For these three cases, DVHs for the PTV, bladder and the rectum were compared. Also, the dose coverage for the CTV and the shifted CTV were evaluated in which the shifted CTV was a copied and translated virtual CTV toward the rectum inside the PTV, thus occupying the initial position of the overlap air volume, simulating the worst condition for the dose coverage in the target. Among the three options, only density1Opt plan gave clinically acceptable result in terms of target coverage and maximum dose. The airOpt plan gave exceedingly higher dose and excessive dose coverage for the target volume whereas noAirOpt plan gave underdose for the shifted CTV. Therefore, for prostate IMRT plan, having an air region in the PTV, density modification of the included air to the value of one, is suggested, prior to optimization and prescription for the PTV. This idea can be equally applied to any cases including the head and neck cancer with the PTV having the overlapped air region. Further study is being under process.

Comparative evaluation of dose according to changes in rectal gas volume during radiation therapy for cervical cancer : Phantom Study (자궁경부암 방사선치료 시 직장가스 용적 변화에 따른 선량 비교 평가 - Phantom Study)

  • Choi, So Young;Kim, Tae Won;Kim, Min Su;Song, Heung Kwon;Yoon, In Ha;Back, Geum Mun
    • The Journal of Korean Society for Radiation Therapy
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    • v.33
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    • pp.89-97
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    • 2021
  • Purpose: The purpose of this study is to compare and evaluate the dose change according to the gas volume variations in the rectum, which was not included in the treatment plan during radiation therapy for cervical cancer. Materials and methods: Static Intensity Modulated Radiation Therapy (S-IMRT) using a 9-field and Volumetric Modulated Arc Therapy (VMAT) using 2 full-arcs were established with treatment planning system on Computed Tomography images of a human phantom. Random gas parameters were included in the Planning Target Volume(PTV) with a maximum change of 2.0 cm in increments of 0.5 cm. Then, the Conformity Index (CI), Homogeneity Index (HI) and PTV Dmax for the target volume were calculated, and the minimum dose (Dmin), mean dose (Dmean) and Maximum Dose (Dmax) were calculated and compared for OAR(organs at risk). For statistical analysis, T-test was performed to obtain a p-value, where the significance level was set to 0.05. Result: The HI coefficients of determination(R2) of S-IMRT and VMAT were 0.9423 and 0.8223, respectively, indicating a relatively clear correlation, and PTV Dmax was found to increase up to 2.8% as the volume of a given gas parameter increased. In case of OAR evaluation, the dose in the bladder did not change with gas volume while a significant dose difference of more than Dmean 700 cGy was confirmed in rectum using both treatment plans at gas volumes of 1.0 cm or more. In all values except for Dmean of bladder, p-value was less than 0.05, confirming a statistically significant difference. Conclusion: In the case of gas generation not considered in the reference treatment plan, as the amount of gas increased, the dose difference at PTV and the dose delivered to the rectum increased. Therefore, during radiation therapy, it is necessary to make efforts to minimize the dose transmission error caused by a large amount of gas volumes in the rectum. Further studies will be necessary to evaluate dose transmission by not only varying the gas volume but also where the gas was located in the treatment field.

The Study of Shielding Effect on Ovoids of Three Different Gynecological Applicator Sets in microSelectron-HDR System (microSelectron-HDR System에서 부인암 강내조사에 쓰이는 세 가지 Applicator Set들의 Ovoids에 대한 차폐효과 연구)

  • Cho, Young-K.;Park, Sung-Y.;Choi, Jin-H.;Kim, Hung-J.;Kim, Woo-C.;Loh, John-J.K.;Kim, Joo-Y.
    • Journal of Radiation Protection and Research
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    • v.23 no.4
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    • pp.259-266
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    • 1998
  • There are three different types of gynecological applicator sets available in microSelectron-high dose-rate(HDR) System by Nucletron; standard applicator set(SAS), standard shielded applicator set(SSAS), and Fletcher-Williamson applicator set(FWAS). Shielding effect of a SAS without shielding material was compared with that of a SSAS with shielding material made of stainless steel(density ${\varrho}=8,000kg/m^3$) at the top and bottom of each ovoid, and of a FWAS with shielding material made of tungsten alloy(density ${\varrho}=14,000kg/m^3$ at the top and bottom of each ovoid. The shielding effects to the rectum and bladder of these two shielded applicator sets were to be measured at reference points with an ion chamber and specially designed supporting system for applicator ovoids inside of the computerized 3-dimensional water phantom. To determine the middle point of two ovoids the measurement was performed with the reference tip of ion chamber placed at the same level and at the middle point from the two ovoids, while scanning the dose with the ion chamber on each side of ovoids. The doses to the reference points of rectum were measured at 20(Rl), 25(R2), 30(R3), 40(R4), 50(R5), and 60(R6) mm located posteriorly on the vertical line drawn from M5(the middle dwell position of ovoid), and the doses to the bladder were measured at 20(Bl), 30(B2), 40(B3), 50(B4), and 60(B5) mm located anteriorly on the vertical line drawn from M5. The same technique was employed to measure the doses on each reference point of both SSAS and FWAS. The differences of measured rectal doses at 25 mm(R2) and 30 mm(R3) between SAS and SSAS were 8.0 % and 6.0 %: 25.0% and 23.0 % between SAS and FWAS. The differences of measured bladder doses at 20 mm(Bl) and 30 mm(B2) between SAS and SSAS were 8.0 % and 3.0 %: 23.0 % and 17.0 % between SAS and FWAS. The maximum shielding effects to the rectum and bladder of SSAS were 8.0 % and 8.0 %, whereas those of FWAS were 26.0 % and 23.0 %, respectively. These results led to the conclusion that FWAS has much better shielding effect than SSAS does, and when SSAS and FWAS were used for gynecological intracavitary brachytherapy in microSelectron-HDR system, the dose to the rectum and bladder was significantly reduced to optimize the treatment outcome and to lower the complication rates in the rectum and bladder.

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A Case of Primary Rectal Colon Mucosa associated Lymphoid Tissue Lymphoma (직장 용종의 형태로 발견된 Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma)

  • Park, Jun-Suk;Jang, Byung-Ik;Choi, Jun-Hyuk;Kim, Kyeong-Ok;Gu, Min-Geun;Kang, Min-Kyu
    • Journal of Yeungnam Medical Science
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    • v.27 no.2
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    • pp.150-154
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    • 2010
  • The gastrointestinal tract(GI) is the most frequently involved site of mucosa associated lymphoid tissue(MALT) lymphoma. Stomach is the most common site of involvement among the GI tract. In some case of MALT lymphoma, it is detected in colon. Almost all diagnosis is established by pathological examination of the surgical or endoscopic specimens. We reported a case of rectal MALT lymphoma by colonoscopic polypectomy.

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Gastrointestinal hemangioma in childhood: a rare cause of gastrointestinal bleeding

  • Han, Eon Chul;Kim, Soo-Hong;Kim, Hyun-Young;Jung, Sung-Eun;Park, Kwi-Won
    • Clinical and Experimental Pediatrics
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    • v.57 no.5
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    • pp.245-249
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    • 2014
  • Gastrointestinal (GI) hemangiomas are relatively rare benign vascular tumors. The choice of an appropriate diagnostic method depends on patient age, anatomic location, and presenting symptoms. However, GI hemangiomas are not a common suspected cause of GI bleeding in children because of their rarity. Based on medical history, laboratory results, and imaging study findings, the patient could be treated with either medication or surgery. Herein, we report 3 cases of GI hemangioma found in the small bowel, rectum, and GI tract (multiple hemangiomas). Better knowledge and understanding of GI hemangioma could help reduce the delayed diagnosis rate and prevent inappropriate management. Although rare, GI hemangiomas should be considered in the differential diagnosis of GI bleeding.

Synthesis of [18F]Fluorocholine Analogues as a Potential Imaging Agent for PET Studies

  • Yu, Kook-Hyun;Park, Jeong-Hoon;Yang, Seung-Dae
    • Bulletin of the Korean Chemical Society
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    • v.25 no.4
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    • pp.506-510
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    • 2004
  • There have been intensive studies concerning $[^{11}F]$choline ($[^{11}F]$methyldimethyl( ${\beta}$ -hydroxyethyl) ammonium) (1) which is known as a very effective tracer in imaging various human tumors localized in brain, lung, esophagus, rectum, prostate and urinary bladder using Positron Emission Tomography (PET) and there is increasing interest in $^{18}F$ labelled choline (2) and proved to be useful to visualize prostate cancer. We have prepared six $^{18}F$ labelled alkyl choline derivatives (3a-3c, 4a-4c) from ditosylated and dibrominated alkanes in moderate yields. The six alkyl tosylate or bromate ammonium salts have been synthesized as precursors. Radiofluorination was achieved by the treatment of precursors with $^{18}F$ - in the presence of Kryptofix-2.2.2.. The labeling yields varied ranging from 7 to 25%.

Calibration and Design of amulatory digital urodynamic study system (휴대용 디지털 요역동학검사장비의 설계와 Calibration)

  • Yoon, Dae-Young;Kim, Keo-Sik;Seo, Jeong-Hwan;Kim, Kyeong-Seop;Song, Chul-Gyu;Yang, Young-Kwang;Lee, Sang-Ok
    • Proceedings of the KIEE Conference
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    • 2004.11c
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    • pp.313-315
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    • 2004
  • Urodynamic study system is widely used for neurogenic bladder patients in various clinical setting. Generally they include 2 pressure sensors from bladder and rectum, and 1 EMG sensor. The rectal pressure catheter is often the source of data error because of gas passage and the fall out of the catheter from anus, and source of discomfort in ambulatory urodynamic system. This study is to design and calibrate the ambulatory digital urodynamic study system that can discard the rectal pressure catheter, which can make patients more comfortable and doctors can get more physiologic data. As a first step, we compared our new system with Dantec $Duet^{(r)}$ urodynamic system (Dantec, Denmark) and wanted to see the possibility of our new system.

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Hirschsprung's Disease Associated with Neonatal Intestinal Perforation (장 천공을 동반한 Hirschsprung씨 병 3예 보고)

  • Kim, Seong-Chul;Sea, Byong-Sun;Liu, Shan King;Kim, In-Koo
    • Advances in pediatric surgery
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    • v.1 no.2
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    • pp.186-189
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    • 1995
  • Neonatal intestinal perforation is mainly caused by necrotizing enterocolitis, intestinal atresia, meconium ileus or unknown etiology. Occasionally, Hirschsprung's disease presents with neonatal intestinal perforation, of which, it is known that total colonic aganglionosis is common. Therefore, Hirschsprung's disease should be considered as a cause of neonatal intestinal perforation. The authors have experienced 3 cases of neonatal Hirschsprung's disease associated with colonic perforations. Cecal perforations were noted in 2 cases with aganglionosis from descending colon and sigmoid perforation in a case with aganglionosis in rectum. These cases will be discussed with literature review.

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