• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.9-16
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• 2018

Purpose : Brain Stereotactic Radiosurgery can treat non-invasive diseases with high rates of complications due to surgical operations. However, brain stereotactic radiosurgery may be accompanied by radiation induced side effects such as fractionation radiation therapy because it uses radiation. The effects of Coplanar Volumetric Modulated Arc Therapy(C-VMAT) and Non-Coplanar Volumetric Modulated Arc Therapy(NC-VMAT) on surrounding normal tissues were analyzed in order to reduce the side effects caused fractionation radiation therapy such as head and neck. But, brain stereotactic radiosurgery these contents were not analyzed. In this study, we evaluated the usefulness of NC-VMAT by comparing and analyzing C-VMAT and NC-VMAT in patients who underwent brain stereotactic radiosurgery. Methods and materials : With C-VMAT and NC-VMAT, 13 treatment plans for brain stereotactic radiosurgery were established. The Planning Target Volume ranged from a minimum of 0.78 cc to a maximum of 12.26 cc, Prescription doses were prescribed between 15 and 24 Gy. Treatment machine was TrueBeam STx (Varian Medical Systems, USA). The energy used in the treatment plan was 6 MV Flattening Filter Free (6FFF) X-ray. The C-VMAT treatment plan used a half 2 arc or full 2 arc treatment plan, and the NC-VMAT treatment plan used 3 to 7 Arc 40 to 190 degrees. The angle of the couch was planned to be 3-7 angles. Results : The mean value of the maximum dose was $105.1{\pm}1.37%$ in C-VMAT and $105.8{\pm}1.71%$ in NC-VMAT. Conformity index of C-VMAT was $1.08{\pm}0.08$ and homogeneity index was $1.03{\pm}0.01$. Conformity index of NC-VMAT was $1.17{\pm}0.1$ and homogeneity index was $1.04{\pm}0.01$. $V_2$, $V_8$, $V_{12}$, $V_{18}$, $V_{24}$ of the brain were $176{\pm}149.36cc$, $31.50{\pm}25.03cc$, $16.53{\pm}12.63cc$, $8.60{\pm}6.87cc$ and $4.03{\pm}3.43cc$ in the C-VMAT and $135.55{\pm}115.93cc$, $24.34{\pm}17.68cc$, $14.74{\pm}10.97cc$, $8.55{\pm}6.79cc$, $4.23{\pm}3.48cc$. Conclusions : The maximum dose, conformity index, and homogeneity index showed no significant difference between C-VMAT and NC-VMAT. $V_2$ to $V_{18}$ of the brain showed a difference of at least 0.5 % to 48 %. $V_{19}$ to $V_{24}$ of the brain showed a difference of at least 0.4 % to 4.8 %. When we compare the mean value of $V_{12}$ that Radione-crosis begins to generate, NC-VMAT has about 12.2 % less amount than C-VMAT. These results suggest that if NC-VMAT is used, the volume of $V_2$ to $V_{18}$ can be reduced, which can reduce Radionecrosis.

• Progress in Medical Physics
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• v.24 no.4
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• pp.265-270
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• 2013

Correct target volume delineation is an important part of radiosurgery treatment planning process. We designed head phantom and performed target delineation to evaluate the volume differences due to radiosurgery treatment planning systems and image acquisition system, CT/MR. Delineated mean target volume from CT scan images was $2.23{\pm}0.08cm^3$ on BrainSCAN (NOVALS), $2.13{\pm}0.07cm^3$ on Leksell gamma plan (Gamma Knife) and $2.24{\pm}0.10cm^3$ on Multi plan (Cyber Knife). For MR images, $2.08{\pm}0.06cm^3$ on BrainSCAN, $1.94{\pm}0.05cm^3$ on Leksell gamma plan and $2.15{\pm}0.06cm^3$ on Multi plan. As a result, Differences of delineated mean target volume due to radiotherapy planning system was 3% to 6%. And overall mean target volume from CT scan images was 6.36% larger than those of MR scan images.

• Journal of the Korean Society of Radiology
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• v.6 no.6
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• pp.521-529
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• 2012

The aim of this study was to analyze radiological change of Kager's triangle area and retrocalcaneal surface temperature by shoes heel height. Area of Kager's triangle was measured by simple radiography study And PACS of INFINITI. Retrocalcaneal surface temperature were measured by DITI. Area of Kager's triangle and retrocalcaneal surface temperature were calculated for comparison and analysis, with flat shoes and high heel shoes. Area of Kager's triangle($0.88cm^2$) and retrocalcaneal surface temperature ($1.4^{\circ}C$)tends to decrease with high heel shoes. The highest and shortest of the Kager's triangle area and a surface temperature difference between flat shoes and high heel shoes, each $0.9cm^2$, $1.2cm^2$, $1.6^{\circ}C$, $0.5^{\circ}C$ and showed slight differences. The highest weight and the lowest weight of a surface area and the temperature difference between flat shoes and high heels, each $1.8cm^2$, $0.8cm^2$, $1.1^{\circ}C$, $0.2^{\circ}C$ and higher weight Kager's area and the surface temperature is decreased. The longest time and shortest time of a surface area and the temperature difference between high heels, each $0.8cm^2$, $1.4^{\circ}C$. In conclusion, Areas of Kager's triangle and retrocalcaneal surface temperature decrease with high heel shoes. If we wear high heel shoes for a long time, retrocalcaneal pain and blood flow disorder will occurs.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.423-429
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• 2002

Recently, the clinical uses of flowable composite resins have increased because of fast, convenient and excellent accessibility, but little has been reported about physical properties of flowable resins. The purpose of this study was to measure and compare the physical properties(compressive strength, relative flowability, relative radiopacity) of 4 contemporary flowable composite resins(Filtek flow, Tetric Flow, Revolution Palfique Estelite LV high flow). The results were as follows; 1. There were no significant differences between 4 flowable composite resins in compressive strength, but all were lower than that of traditional hybrid composite resin(p<0.001). 2. The relative flowability were increased in order of Palfique Estelite LV high flow, Revolution, Filtek flow, Tetric Flow and sealant(p<0.001), but there were no significant differences between Filtek flow and Tetric Flow. 3. There were significant differences between flowable composite resins in relative radiopacity and they showed similar or higher radiopacity than dentin(p<0.001), especially Tetric Flow and Filtek Flow showed higher radiopacity than enamel(p<0.001). This results suggested that the stress of application area have to be considered since flowable composite resins have lower compressive strength than hybrid composite, and the differences of flowability between these flowable composite resins can be considered when they are selected. All tested flowable composite resins showed optimal radiopacity to ISO's recommend.

• Radiation Oncology Journal
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• v.21 no.3
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• pp.192-198
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• 2003

Purpose: Current results of autologous stem cell transplantation (SCT) suggest that this procedure may prolong disease free survival In patients with acute myeloid leukemia (AML). Autologous SCT is increasingly used as treatment for AML in first remission. The aim of this study was to evaluate the outcome of autologous SCT for patients with AML in first remission treated by autologous SCT using cytarabine, melphalan and total body irradiation (TBI) as the conditioning regimen. Materials and Methods: Between January 1995 and December 1999, 29 patients with AML in first remission underwent autologous SCT. The median age of patients was 33 years (range, 16 to 47). The conditioning regimen consisted of cytarabine ($3.0\;gm/m^2$ for 3 days), melphalan ($100\;gm/m^2$ for 1 day) and TBI (total 1000 cGy in five fractions over 3 days). Results: The median follow up was 40 months with a range of 3 to 58 months. The 4-year cumulative probability of disease free survival was 69.0%, and median survival was 41.5 months. The 4-year relapse rate was 27.6%. The factor Influencing disease free survival and relapse rate was the French-American-British (FAB) classification ($M_3$ group vs. other groups; p=0.048, p=0.043). One patient died from treatment-related toxicity. Conclusion:: Although the small number of patients does not allow us to draw any firm conclusion, our results were encouraging and suggest that the association of cytarabine, melphalan and TBI as a conditioning regimen for autologous SCT for AML on first remission appears to be safe and effective.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.455-467
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• 1998

Purpose : To evaluate influences associated with radiation treatment planning obtained with the patient breathing freely. Materials and Methods : We compared reduction or elimination of planning target volume (PTV) margins with 2-D conventional plan with inclusion of PTV margins associated with breathing with 3-D conformal therapy. The respiratory non gated 3-D conformal treatment plans were compared with respiratory gated conventional 2-D plans in 4 patients with hepatocellular carcinomas. Isodose distribution, dose statistics, and dose volume histogram (DVH) of PTVs were used to evaluate differences between respiratory gated conventional 2-D plans and respiratory non gated 3-D conformal treatment plans. In addition. the risk of radiation exposure of surrounding normal liver and organs are evaluated by means of DVH and normal tissue complication probabilities (NTCPs). Results : The vertical movement of liver ranged 2-3 cm in all patients. We found no difference between respiratory gated 2-D plans and 3-D conformal treatment plans with the patients breathing freely. Treatment planning using DVH analysis of PTV and the normal liver was used for all patients. DVH and calculated NTCP showed no difference in respiratory gated 2-D plans and respiratory non gated 3-D conformal treatment plans. Conclusion : Respiratory gated radiation therapy was very important in hepatic tumors because radiation induced hepatitis was dependent on remaining normal liver volume. Further investigational studies for respiratory gated radiation.

• Radiation Oncology Journal
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• v.11 no.2
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• pp.363-367
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• 1993

A retrospective analysis was peformed on 42 patients with carcinoma of the uterine cervix who were treated with external beam (EB) radiation therapy alone at the Department of Therapeutic Radiology, Seoul National University Hospital from March 1979 to December 1988. After whole pelvic field irradiation of 50Gy, all the patients received additional booster dose of 12-22Gy to the primary tumor Thirty one received EB radiotherapy alone because of poor geometry for intracavitary application,5 because of medical problems and 6 because of other reasons. Five year locoregional control rate and five year survival rate were $34.5\%\;and\;35.4\%,$ respectively. Five year survivals were $66.7\%,\;36.4%,\;32.8\%\;and\;25.0\%$ for stage IIA, IIB, IIIB and IVA, respectively. The response one month after treatment well correlated with prognosis. The incidence of grade 2 and 3 complication was $12\%\;and\;10\%,$ respectively. There was tendency of increased complication with advanced stage.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.14 no.1
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• pp.153-161
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• 1984

Orthopantomograph는 치과진료에서 가장 일반적인 국외촬영방법으로 이용되고 있다. 저자는 1983년 서울대학교병원 치과진료부 치과방사선과에 래원한 환자중 Orthopantomogram을 촬영한 2,160명을 대상으로 골경화증의 성별, 연령별 발생빈도와 발생부위, 경화상의 크기, 모양등을 분류하고 특발성 골경화증과 condensing osteitis에 관하여 관찰하였든 바 다음과 같은 결과를 얻었다. 1. Idiopathic osteosclerosis의 발현율은 16.0%, condensing osteitis의 발현율은 9.8%였고 남녀간의 차이는 없었다. 2. 골경화증의 호발부위는 하악소구치, 대구치부위였고, 상악에서의 발생율은 적었다. 3. 골경화상의 크기는 idiopathic osteosclerosis는 10㎜이내였고, condensing osteitis는 10-20㎜의 폭경을 가지고 있었다. 4. 골경화상의 형태, 건강골과의 경계 및 발현되는 상태는 일정하지 않았다.

• The Journal of Korean Society for Radiation Therapy
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• v.32
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• pp.85-92
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• 2020

Purpose: To find out the advantages of thermoplastic bolus compared to conventional bolus, which is mainly used in clinical practice, We evaluated Two cases in terms of dose and location reproducibility to assess Usability of thermoplastic Bolus for skin VMAT radiotherapy. Materials and Methods: Two patient's treated with left breast skin lesion were simulated using thermoplastic Bolus and planned with 2arc VMAT. the prescription dose was irradiated to 95% or more of the target volume. We evaluated The reproducibility of the bolus position by measuring the length of the air gap in the CBCT (Cone Beam CT) image. to evaluate dose reproducibility, we compared The dose distribution in the plan and CBCT and measured in vivo for patient 2. Results: The difference between the air gap in patient 1's simulation CT and the mean air gap (M1) during 10 treatments in the CBCT image was -0.42±1.24mm. In patient 2, the difference between the average air gap between the skin and the bolus (M2) during 14 treatments was -1.08±1.3mm, and the air gap between the bolus (M3) was 0.49±1.16. The difference in the dose distribution between Plan CT and CBCT was -1.38% for PTV1 D95 and 0.39% for SKIN (max) in patient 1. In patient 2, PTV1 D95 showed a difference of 0.63% and SKIN (max) -0.53%. The in vivo measurement showed a difference of -1.47% from the planned dose. Conclusion: thermoplastic Bolus is simpler and takes less time to manufacture compared to those produced by 3D printer. Also compared to conventional bolus, it has high reproducibility in the set-up side and stable results in terms of dose delivery.

• Radiation Oncology Journal
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• v.19 no.3
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• pp.230-236
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• 2001

Purpose : To evaluate treatment results in terms of local control, complications and survival after reirraidiation in recurrent cervical cancer following definite radiation therapy. Material and methods : From November 1987 through March 1998, eighteen patients with recurrent cervical cancer following definite radiation therapy were subsequently treated with reirradiation at Keimyung University Dongsan Medical Center. In regard to the initial FIGO stage, one patient was stage la, five were stage IIa, three were IIb, two were IIb and two were IVa. The age range was 37 to 79 years old with median age of 57. The time interval from initial definite radiation therapy to recurrence ranged from 6 to 122 months with a median of 58 months. The recurrent sites were the uterine cervix in seven patients, vagina in ten and pelvic lymph node in one. Reirradiation was peformed with external radiation and intracavitary radiation in twelve patients, external radiation and implantation in four and external radiation alone in two. The range of external radiation dose was $2,100\~5,400\;cGy$ and the range of the total radiation dose was $3,780\~8,550\;cGy$. The follow-up periods ranged from 8 to 20 months with median of 25 following reirradiation. Results : Fourteen of eighteen patients $(78\%)$ had local control just after reirradiation. The two year disease free survival (2YDFS) rate was $53.6\%$. There were statistically significant differences in the 2YDFS according to both recurrent site (2YDFS $28.5\%$ in uterine cervix, $71.4\%$ in vagina, (p=0.03)) and the total dose (2YDFS $71.8\%$ in >6,000 cGy , $25\%$ in $\leq6,000$ cGy, p=0.007). Seven of ten patients who were followed for more than 20 months remain alive and disease free (7/18, $39\%$). Patients treated with external radiation and intracavitary radiation had a higher rate of 2YDFS. Seven patients including 4 patients with no local control experienced local failure in the uterus or vagina and two patients died with distant metastasis. Complications included rectal bleeding in 3 patients, bowel obstruction treated with surgery in two, hematuria in one, radiation cystitis in two, soft tissue swelling in two and vaginal necrosis spontaneously healed in one. There was no statistical difference in complications according to the total dose or the time to recurrence from initial radiation. Conclusion : In patients with recurrence following definite radiation therapy in the uterine cervical cancer, reirradiation may be effective but requires an effort to reduce radiation induced severe complications.