• Journal of radiological science and technology
• /
• v.38 no.1
• /
• pp.1-6
• /
• 2015

Whole spine scanography (WSS) is a radiological examination that exposes the whole body of the individual being examined to x-ray radiation. WSS is often repeated during the treatment period, which results in a much greater radiation exposure than that in routine x-ray examinations. The aims of the current study were to evaluate the patient dose of WSS using computer simulation, image magnification and angulation of phantom image using different patient position. We evaluated the effective dose(ED) of 23 consecutive patients (M : F = 13:10) who underwent WSS, based on the automatic image pasting method for multiple exposure digital radiography. The Anterior-Posterior position(AP) and Posterior-Anterior position( PA) projection EDs were evaluated based on the PC based Monte Carlo simulation. We measured spine transverse process distance and angulation using DICOM measurement. For all patient, the average ED was 0.069 mSv for AP position and 0.0361 mSv for PA position. AP position calculated double exposure then PA position. For male patient, the average ED was 0.089 mSv(AP) and 0.050 mSv(PA). For female patient, the average ED was 0.0431 mSv(AP) and 0.026 mSv(PA). The transverse process of PA spine image measured 5% higher than AP but angulation of transverse process was no significant differences. In clinical practice, just by change the patient position was conformed to reduce the ED of patient. Therefor we need to redefine of protocol for digital radiography such as WSS. whole spine scanography, effective dose, patient exposure dose, exposure direction. protocol optimization.

• FLOWER RESEARCH JOURNAL
• /
• v.16 no.2
• /
• pp.128-133
• /
• 2008

This study was conducted to select new variants with different characteristics in plant height, leaf color, and petal color of plantain lily (Hosta plantaginea) and Japanese farfugium (Farfugium japonicum). After 10-30Gy ${\gamma}-ray$ irradiation to seeds of both species, seed germination, variant induction, growth of variants, and survival ratios were estimated. Days required for seed germination were lengthened and % seed germination decreased as the dosage of ${\gamma}-ray$ increased over 20Gy. Lethal dose ($LD_{50}$) for plantain lily and Japanese farfugium were 30Gy and 25Gy, respectively. Plantain lily and Japanese farfugium treated by more than 20Gy ${\gamma}-ray$ showed dwarf characteristics in growth, and variations in leaf and petal colors. Total 166 variants in plantain lily were induced by ${\gamma}-ray$ irradiation in a $M_1$ generation, among which 12 promising variants were selected in a $M_2$ generation. Total 57 variants of Japanese farfugium were induced by ${\gamma}-ray$ irradiation in a $M_1$ generation, among which nine promising variants were selected in a $M_2$ generation.

• Radiation Oncology Journal
• /
• v.3 no.2
• /
• pp.95-101
• /
• 1985

From July 1979 through March 1985,112 patients with carcinoma of the uterine cervix were treated by whole pelvis irradiation and intracavitary radiation with Cs-137. The treatment consisted of 3600rad-5200rad to the whole pelvis by parallel opposing portals, 5 days per week, 180-200rad per day. Parametrial boost with 400-800rad was given in 60 patients. 2 intracavitary Cs-137 radiation using TAO applicator were done with 7-10 days interval. Total treatment times were 40-65 days with average 52 days. Total dose of radiation to point A varied from 6820 to 10500rad with average 8388rad and to point B from 4850 to 6899ra0 with average 5898rad. All patients had follow up from 6 months to 75 months and median follow up of 31 months. $9(8\%)$ had stage $14(12.5\%)$ had stage IIa, $50(44.6\%)$ had stage IIb, $33(29.5\%)$ had stage III, $6(5.4\%)$ had stage IV. 110 patients had squamous cell carcinoma and 2 patients had adenocarcinoma. 5 year actuarial survival rates were $61.8\%$ for the entire group, $84.6\%$ for stage Ib,$77.8\%$ for stage IIa, $56.7\%$ for stage IIb, $60\%$ for stage III, $33.3\%$ for stage IV. RT dose to medial parametrium (point A) below 8000rad resulted in $7/18(38.9\%)$ failure (=death) in contrast to 25/94 $(26.5\%)$ failure with dose over 8000rad. RT dose to lateral parametrium (point B) below 6000ra0 yielded 20/63 $(34.9\%)$ failure compared to $10/49(20.4\%)$ failure with dose over 6000rad. Poor survival group of age were between 40-49 years with failure of $14/41(34.1\%)$. There was no increased failure rate below age of 40 with failure of $2111(13.9\%)$. The results suggest that survival is as good as other published data, and that higher doses over 8000rad to point A and 6000rad to point B should be delivered.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2003.09a
• /
• pp.60-60
• /
• 2003

목적 : 감마나이프 치료계획용 소프트웨어인 감마플렌에서 처방선량을 계산하는 단위와 실제 시간을 설정하는 하드웨어인 조정판의 시간설정 단위의 차이에 의한 실제 처방선량에 끼치는 영향을 계산하였다. 대상 및 방법 : 감마나이프는 주어진 4 개의 헬멧을 가지고 최소 한번 또는 최대 20 번 이상의 방사선 조합으로 한번에 많은 방사선을 목표물에 조사한다. 감마나이프 방사선 수술을 위한 치료계획용 소프트웨어인 감마플렌 5.32에서는 처방선량에 대한 치료시간을 최대 지점 또는 지정하는 지점에 규격화하여 소숫점 두 자리 즉 0.6 초까지 계산한다. 그러나 실제 치료를 위한 조정판의 시간설정은 모델 B 에서는 소숫점 한자리까지 가능하게 되어있다. 그러므로 모델 B를 사용하는 기관의 치료계획 컴퓨터인 감마플렌에서는 소숫점 한자리로 만들기 위해 반올림과 내림을 하게 되며 이것을 프린트하여 사용하게 된다. 실제 임상에서 멀티삿에 대한 반올림과 내림에 대한 효과를 선량으로 환산하여 처방선량에 끼치는 영향을 연구하였다. 치료 계획에 서 처방선량을 입력한 후 계산된 각 조사에 대한 소숫점 두자리 시간을 화면에 표시한 후 스냅tit으로 스크린 캡쳐하여 프린트하였으며, 소숫점 한자리로 된 최종 치료계획을 프린트하여 서로 비교 계산하였다. 결과 : 20 여명의 환자에 대한 치료 결과에 대한 분석은 조사의 수나 처방선량에 관계하지 않고 우연히 올림이 많으냐 내림이 많으냐에 의존하였다. 최대지점에 대하여 분석한 결과는 -0.48부터 +0.47로 -2%부터 +1.9%의 정도로 영향을 끼쳤다. 결론 : 반올림과 내림의 결과는 처방선량을 줄일 수도 있고 늘일 수도 있었다. 그러나 이 연구는 최대선량 지점에 대해 비교를 하였으나 실제로는 각 조사의 위치가 서로 다르므로 영향은 이보다 훨씬 적을 것으로 생각되어 소숫점 한자리로 치료하여도 무방할 것으로 보인다.mm, AP 방향에서는 2.1$\pm$0.82 mm이었다. 그리고 복부의 later의 방향에서는 7.0$\pm$2.1 mm, AP 방향에서는 6.5$\pm$2.2 mm 이었다. 또한 표적 위치측정을 위해서 환자의 피부에 임의의 가상표적을 부착하고 CT 촬영한 영상결과, 프레임으로 가상표 적에 대한 위치를 정확히 파악할 수 있었다. 결론 : 제작된 프레임을 적용하여 방사선투과율 측정실험, 환자 외부자세에 대한 오차 측정실험, 가상표적 위치측정 실험 등을 수행하였다. 환자 외부자세에 대한 오차 측정실험 경우, 더 많은 Volunteer를 적용하여 보다 정확한 오차 측정실험이 수행되어야 할 것이며 정확한 표적 위치 측정실험을 위해서 내부 마커를 삽입한 환자를 적용한 임상실험이 수행되어야 할 것이다. 또한 위치결정에서 획득한 좌표값의 정확성을 알아보기 위해서 팬톰을 이용한 방사선조사 실험이 추후에 실행되어져야 할 것이다. 그리고 제작된 프레임에 Rotating X선 시스템과 내부 장기의 움직임을 계량화하고 PTV에서의 최적 여유폭을 설정함으로써 정위 방사선수술 및 3 차원 업체 방사선치료에 대한 병소 위치측정과 환자의 자세에 대한 setup 오차측정 결정에 도움이 될 수 있을 것이라고 사료된다. 상대적으로 우수한 것으로 나타났으며, 혼합충전재는 암모니아의 경우 코코넛과 펄라이트의 비율이 7：3인 혼합 재료 3번과 소나무수피와 펄라이트의 비율이 7：3인 혼합 재료 6번에서 다른 혼합 재료에 비하여 우수한 것으로 나타났다. 4. 코코넛과 소나무수피의 경우 암모니아 가스에 대한 흡착 능력은 거의 비슷한 것으로 사료되며, 코코넛의 경우 전량을 수입에 의존하고 있다는 점에서 국내 조달이 용이하며, 구입 비용도 적게 소요되는 소나무수피를 사용하는 것이 경제적이라고 사료된다. 5. 마지막으로

• Progress in Medical Physics
• /
• v.2 no.2
• /
• pp.109-120
• /
• 1991

Total body irradiation is operated to irradicate malignant cells of bone marrow of patients to be treated with bone marrow transplantation. Field size of a linear accelerator or cobalt teletherapy unit with normal geometry for routine technique is too small to cover whole body of a patient. So, any special method to cover patient whole body must be developed. Because such environments as room conditions and machine design are not universal, some characteristic method of TBI for each hospital could be developed. At Seoul National University Hospital, at present, only a cobalt unit is available for TBI because source head of the unit could be tilted. When the head is tilted outward by 90$^{\circ}$, beam direction is horizontal and perpendicular to opposite wall. Then, the distance from cobalt source to the wall was 319 cm. Provided that the distance from the wall to midsagittal plane of a patient is 40cm, nominal field size at the plane(SCD 279cm) is 122cm$\times$122cm but field size by measurement of exposure profile was 130cm$\times$129cm and vertical profile was not symmetric. That field size is large enough to cover total body of a patient when he rests on a couch in a squatting posture. Assuming that average lateral width of patients is 30cm, percent depth dose for SSD 264cm and nominal field size 115.5cm$\times$115.5cm was measured with a plane-parallel chamber in a polystyrene phantom and was linear over depth range 10～20cm. An anthropomorphic phantom of size 25cm wide and 30cm deep. Depth of dose maximum, surface dose and depth of 50% dose were 0.3cm, 82% and 16.9cm, respectively. A dose profile on beam axis for two opposing beams was uniform within 10% for mid-depth dose. Tissue phantom ratio with reference depth 15cm for maximum field size at SCD 279cm was measured in a small polystyrene phantom and was linear over depth range 10～20cm. An anthropomorphic phantom with TLD chips inserted in holes on the largest coronal plane was bilaterally irradiated by 15 minute in each direction by cobalt beam aixs in line with the cross line of the coronal plane and contact surface of sections No. 27 and 28. When doses were normalized with dose at mid-depth on beam axis, doses in head/neck, abdomen and lower lung region were close to reference dose within $\pm$ 10% but doses in upper lung, shoulder and pelvis region were lower than 10% from reference dose. Particulaly, doses in shoulder region were lower than 30%. On this result, the conclusion such that under a geometric condition for TBI with cobalt beam as SNUH radiotherapy departement, compensators for head/neck and lung shielding are not required but boost irradiation to shoulder is required could be induced.

• Progress in Medical Physics
• /
• v.7 no.2
• /
• pp.29-40
• /
• 1996

We had designed and made the cylindrical ionization chamber which operated above 5 mR/h. Using commercial electrometer, we investigated the characterictic of charge collection in the ion chamber. The active volume was 190.4㎤ and overall length and diameter in the chamber was 15.5cm, 5.22cm, respectively. The chamber had three electrodes(inner, central, wall electrode). And background current was 8.39${\times}$10$\^$-14/${\pm}$1.5${\times}$10$\^$-15/A to arrange the electrodes which were coaxial in chamber axis. The collection efficiency of chamber for Cs$\^$137/ was 99.7％ when the opreating voltage was applied 400V. Comparing with the commertial dosimetry system, the exposure calibration constant was 4.531${\times}$19$\^$7/R/C. By normalizing to CS$\_$137/ the relative energy response of the chamber was 1.30 for Am$\_$24/, 1.05 for C0$\_$60/, respectively. When the irrarition tranversed to the chamber axis, the isotropic effect of the chamber was not considerable.

• Polymer(Korea)
• /
• v.33 no.3
• /
• pp.268-271
• /
• 2009

In this study, the distribution behaviors of the polystyrene sulfonic acid (PSSA) grafting polymer across the FEP-g-PSSA membranes prepared by a simultaneous irradiation method, were investigated by analyzing the cross-section of the membranes with a SEM-EDX instrument. The effects of irradiation conditions such as the degree of grafting, FEP film thickness, and grafting solvent on the distribution of the grafting polymer were mainly studied in this experiment. The results indicate that to obtain the evenly grafted FEP-g-PSSA membranes, the higher degree of grafting is required as the film thickness increases, and the lower dose rate are more effective than the higher dose rate at the given dose.

• Progress in Medical Physics
• /
• v.13 no.2
• /
• pp.74-78
• /
• 2002

The individual (customized) immobilization has been used to reproduce the patients' set-up on daily base. There are many various devices available commercially. To evaluate dosimetric characteristics of vacuum cushion, we analysed the surface dose and transmission factor for d$_{max}$ when patient is immobilized with vacuum cushion. Experiments were performed with 4 MV (Varian 4/100, USA), 6 MV, 15 MV (Varian CL2100C/D, USA) photon beams and five field sizes (5$\times$5, 10$\times$10, 20$\times$20, 30$\times$30, 40$\times$40 $\textrm{cm}^2$) on each occasion. Outputs were measured from surface of polysterene phantom to d$_{max}$ with four different thicknesses of cushion, which is 12, 32, 48 mm and only vinyl without styroforms. As results, the transmission factor for thicknesses of vacuum cushion was ranged from 0.9953 to 1.0043. The more the thickness of vacuum cushion is thick, the more surface dose delivered to patient is increased. The surface dose vary with the thickness of vacuum cushion for energy and field size. The skin reactions may result. But the variation is not serious in the clinic.

• Korean Journal of Environmental Agriculture
• /
• v.17 no.3
• /
• pp.274-278
• /
• 1998

To observe the stimulating effects of low-dose ${\gamma}-radiation$ on the Chinese cabbage, $1{\sim}5$ years old seeds were cultivated in the green house and the experimental field after irradiation of $0.5Gy{\sim}30.0Gy$ and the growth characters of them were investigated. The germination rates and the seedling heights of old seeds increased positively in the green house, but different from each other depending on their period of storage. Those of 3-, 4-, and 5-year old seeds increased remarkably at the 4.0Gy-, 1.0Gy-, and 0.5Gy-irradiation group respectively. However, in the case of 1-year and 2-year old seeds, there were not significant effects of irradiation except the increase of seedling height. There were significant increasing effects of radiation on the plant height, fresh weight, and diameter of all seeds grown in the experimental field of 4.0Gy- and 8.0Gy-irradiation group, including the corresponding effects of 1-year and 2-year old seeds in 20.0Gy- and 30.0Gy-irradiation group.

• Radiation Oncology Journal
• /
• v.18 no.3
• /
• pp.182-186
• /
• 2000

Purpose : To determine treatment or이ecol for inoperable esophageal cancer patients, 껜e evaluated survival rate and prognostic factors. Materials and Methods : We evaluated esophageal cancer treated by curative or palliative am in KCCH from 1992 to 1996, retrospectively. Recurrent or underdose case below 40 Gy were excluded. The number of male and female were 35 and 5, respectively. Thirty-eight patients were squamous carcinoma and 2 patients were not biopsy proven. Ten patients were treated with radiation therapy and chemotherapy Median dose of radiation therapy was 59.4 Gy and the range was $40\~60$ Gy. Results : The median survival is 6.5 months and 1-year survival rate was $28.3\%$. Age, location, radiation dose and chemotherapy were not significant prognostic factors. Median survivals of patients with below stage III and over stage IVA were 7.6 and 6.2 months respectively, but it is not significant. Conclusions : The survival for esophageal cancer is very poor. For patients with curative aim, chemotherapy must be considered. For patients with palliative aim, short-term external beam radiation therapy and/or brachytherapy must be considered.