• Journal of Life Science
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• v.23 no.5
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• pp.710-720
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• 2013

Radiotherapy is commonly used in treating many kinds of cancers which cannot be cured by other therapeutic strategies. However, radiotherapy also induces the damages on the normal tissues. Radiation-induced fibrosis is frequently observed in the patients undergoing radiotherapy, and becomes a major obstacle in the treatment of intrahepatic cancer. Hedgehog (Hh) that is an essential in the liver formation during embryogenesis is not detected in the healthy liver, but activated and modulates the repair process in damaged livers in adult. The expression of Hh increases with the degree of liver damage, regulating the proliferation of hepatic progenitors and hepatic stellate cells (HSC). In addition, Hh induces epithelial-to-mesencymal transition (EMT) and activation of myofibroblasts. In the irradiated livers, up-regulated expression of Hh signaling was associated with proliferation of progenitors, EMT induction, and increased fibrosis. Female-specific expression of Hh leaded to the expansion of progenitors and the accumulation of collagen in the irradiated livers of female mice, indicating that gender disparity in Hh expression may be related with radiation-susceptibility in female. Hence, Hh signaling becomes a novel object of studies for fibrogenesis induced by radiation. However, the absence of the established experimental animal models showing the similar physiopathology with human liver diseases and fibrosis-favorable microenvironment hamper the studies for the radiation-induced fibrosis, providing a few descriptive results. Therefore, further research on the association of Hh with radiation-induced fibrosis can identify the cell and tissue-specific effects of Hh and provides the basic knowledge for underlying mechanisms, contributing to developing therapies for preventing the radiation-induced fibrosis.

• 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.

• Radiation Oncology Journal
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• v.19 no.1
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• pp.27-33
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• 2001

Purpose : To evaluate interim results in terms of failure, cosmetic results and survival after breast conserving operation and radiation therapy in early breast cancer. Material and Methods : From January 1992 through December 1997, seventy two patients with early stage 0, I and II breast cancer were treated with conservative surgery plus radiotherapy at Keimyung University Dongsan Medical Center. Age distribution was 25 to 77 years old with median age of 43. According to TNM stage, five patients had stage 0, thirty three were stage I, twenty five were IIa, and nine were IIb. Most patients underwent excision of all gross tumor and ipsilateral axillary dissection. Breast was irradiated through medial and lateral tangential fields of 6 MV photons to 50.4 Gy in 28 fractions over 5.5 weeks. We delivered a boost irradiation dose of 10 to 16 Gy in 1 to 2 weeks to excision site. Adjuvant chemotherapy was administered in forty one patients with CMF (cyclophosphamide, methotrexate, 5-fluorouracil) regimens of 6 cycles concurrently or before radiation. Cosmetic results were assessed by questionnaire to patients grading of excellent, good, fair, poor. Follow-up periods were 22 to 91 months with median 40 months. Results : Five year disease free survival rate (5YDFS) was $95.8\%$. According to stage, 5YDFS was $100\%,\;96.9\%,\;96\%\;and\;88.9\%$ in stage 0, I, IIa and IIb, respectively. Two patients had distant metastasis and one had local and distant failure. One patient with distant failure had bone and liver metastasis at 14 months after treatment and the other had lung and both supraclavicular metastasis at 21 months after treatment. Patient with local and distant failure had local recurrence on other quadrant in same breast and then salvaged with total mastectomy and chemotherapy but she died due to brain metastasis at 55 months. Complications were radiation pneumonitis in five patients (four patients of asymptomatic, one patients of symptomatic) and hand or arm edema(4 patients). Fifty nine patients answered our cosmetic result questionnaire and cosmetic results were good to excellent in fifty one patients $(86\%)$. Conclusion : We considered that conservative surgery and radiation for the treatment of early stage invasive breast cancer was safe and had excellent survival and cosmetic results. We need to assess about prognostic factors with longer follow up and with large number of patients.

• Radiation Oncology Journal
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• v.25 no.2
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• pp.109-117
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• 2007

[ $\underline{Purpose}$ ]: To evaluate the incidences and potential predictive factors for symptomatic radiation pneumonitis (SRP) and radiographic pulmonary toxicity (RPT) following adjuvant radiotherapy (RT) for patients with breast cancer. A particular focus was made to correlate RPT with the dose volume histogram (DVH) parameters based on three-dimensional RT planning (3D-RTP) data. $\underline{Materials\;and\;Methods}$: From September 2003 through February 2006, 171 patients with breast cancer were treated with adjuvant RT following breast surgery. A radiation dose of 50.4 Gy was delivered with tangential photon fields on the whole breast or chest wall. A single anterior oblique photon field for supraclavicular (SCL) nodes was added if indicated. Serial follow-up chest radiographs were reviewed by a chest radiologist. Radiation Therapy Oncology Group (RTOG) toxicity criteria were used for grading SRP and a modified World Health Organization (WHO) grading system was used to evaluate RPT. The overall percentage of the ipsilateral lung volume that received ${\geq}15\;Gy\;(V_{15}),\;20\;Gy\;(V_{20})$, and $30\;Gy\;(V_{30})$ and the mean lung dose (MLD) were calculated. We divided the ipsilateral lung into two territories, and defined separate DVH parameters, i.e., $V_{15\;TNGT},\;V_{20\;TNGT},\;V_{30\;TNGT},\;MLD_{TNGT}$, and $V_{15\;SCL},\;V_{20\;SCL},\;V_{30SCL},\;MLD_{SCL}$ to assess the relationship between these parameters and RPT. $\underline{Results}$: Four patients (2.1%) developed SRP (three with grade 3 and one with grade 2, respectively). There was no significant association of SRP with clinical parameters such as, age, pre-existing lung disease, smoking, chemotherapy, hormonal therapy and regional RT. When 137 patients treated with 3D-RTP were evaluated, 13.9% developed RPT in the tangent (TNGT) territory and 49.2% of 59 patients with regional RT developed RPT in the SCL territory. Regional RT (p<0.001) and age (p=0.039) was significantly correlated with RPT. All DVH parameters except for $V_{15\;TNGT}$ showed a significant correlation with RPT (p<0.05). $MLD_{TNGT}$ was a better predictor for RPT for the TNGT territory than $V_{15\;SCL}$ for the SCL territory. $\underline{Conclusion}$: The incidence of SRP was acceptable with the RT technique that was used. Age and regional RT were significant factors to predict RPT. The DVH parameter was good predictor for RPT for the SCL territory while $MLD_{TNGT}$ was a better predictor for RPT for the TNGT territory.

• Journal of the Korean Society of Radiology
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• v.10 no.3
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• pp.145-152
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• 2016

This study, targeting a cancer patient undergoing radiation treatment, conducted this research with the aim of looking into the relevance between family support belonging to a patient's primary environment, social support consisting of medical personnel, and the quality of life; this study set 199 patients available for investigation from Jan. 25, 2012 until April 30, 2012 as research subjects among the cancer patients undergoing radiation treatment at the Radiation Oncology Department of a university hospital located in Seoul Metropolitan City. In the analysis of collected data, this study conducted t-test using SPSS/WIN 18.0 Statistical Program, and looked into the relevancy between independent variables including social support, and the quality of life as a dependent variable using analysis of variance, correlation analysis and multi-regression analysis. Conclusively, it was found that the higher the family support perceived by a cancer patient undergoing radiation treatment, the higher the quality of his/her life; thus, this study could learn that there exists a significant relation between family support and the quality of life. Accordingly, it is thought that it's necessary to develop an intervention strategy which makes it possible to intensify family support and social support, etc. for the purpose of improving the quality of life of cancer patients undergoing radiation treatment; further, this study thinks that it's necessary to do additional research which could analyze diverse aspects by subdividing the future quality of life by area.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.191-198
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• 2018

This study was conducted to evaluate the clinical effectiveness of proton therapy as an advanced convergent cancer therapy. Clinical data of proton therapy were analyzed. As proton enters patient's body, it releases low dose of energy and shows an increasing energy deposition as it reaches certain point unlike x-ray. It may therefore reduce the radiation dose to the normal tissues in front and beyond the lesion and minimize the radiation damage. Proton therapy is expected to improve clinical outcomes and reduce treatment related toxicities. It is used in various cancers. Further studies are necessary.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.997-999
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• 2012

Digital X-ray image detector is widely used for radiodiagnosis. Amorphous selenium has been received attention as one of the major material that confirmed photoconductor of direct methode detector. We analysis the photocurrent using 2-dimensional device simulator when blue-ray (${\lambda}=486nm$) is irradiated and high voltage is biased. We evaluate electron-hole generation rate, electron-hole recombination rate, and electron/hole distribution in the amorphous selenium. This simulation methode is helpful to the analysis of digital X-ray image detector. We expect that many applications will be developed in digital X-ray image detector using 2-dimensional device simulator.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.1
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• pp.35-41
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• 2006

Purpose: A various find of radiotherapy treatment plans have been made to determine appropriate doses for breasts, chest walls and loco-regional lymphatics in the radiotherapy of breast cancers. The aim of this study was to evaluate the optimum radiotherapy plan technique method by analyzing dose distributions qualitatively and quantitatively. Materials and Methods: To evaluate the optimum breast cancer radiotherapy plan technique, the traditional method(two dimensional method) and computed tomography image are adopted to get breast volume, and they are compared with the three-dimensional conformal radiography (3DCRT) and the intensity modulated radiotherapy (IMRT). For this, the regions of interest (ROI) such as breasts, chest walls, loco-regional lymphatics and lungs were marked on the humanoid phantom, and the computed tomography(Volume, Siemens, USA) was conducted. Using the computed tomography image obtained, radiotherapy treatment plans (XiO 5.2.1, FOCUS, USA) were made and compared with the traditional methods by applying 3DCRT and IMRT. The comparison and analysis were made by analyzing and conducting radiation dose distribution and dose-volume histogram (DVH) based upon radiotherapy techniques (2D, 3DCRT, IMRT) and point doses for the regions of interest. Again, treatment efficiency was evaluated based upon time-labor. Results: It was found that the case of using 3DCRT plan techniques by getting breast volume is more useful than the traditional methods in terms of tumor delineation, beam direction and confirmation of field boundary. Conclusion: It was possible to present the optimum radiotherapy plan techniques through qualitative and quantitative analyses based upon radiotherapy plan techniques in case of breast cancer radiotherapy. However, further studies are required for the problems with patient setup reproducibility arising from the difficulties of planning target volume (PVT) and breast immobilization in case of three-dimensional radiotherapy planning.

• Radiation Oncology Journal
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• v.17 no.2
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• pp.136-140
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• 1999

Purpose : Prostate specific antigen (PSA) is a useful tumor marker, which is widely used as a diagnostic index and predictor of both treatment and follow-up result in prostate cancer. A prospective analysis was carried out to obtain the period of PSA normalization and the half life of PSA and to analyze the factors influencing the period of PSA normalization. The PSA level was checked before and serially after radical radiotherapy. Materials and Method : Twen쇼 patients with clinically localized prostate cancer who underwent radical external beam radiotherapy were enrolled in this study. Accrual period was from April 1993 to May 1998. Median follow-up period was 20 months. Radiotherapy was given to whole pelvis followed by a boost to prostate. Dose range for the whole pelvis was from 45 Gy to 50 Gy and boost dose to prostate, from 14 Gy to 20 Gy. The post-irradiation PSA normal value was under 3.0 ng/ml. The physical examination and serum PSA level evaluation were performed at 3 month interval in the first one year, and then at every 4 to 6 months. Results : PSA value was normalized in nineteen patients (95%) within 12 months. The mean period of PSA normalization was 5.3 (${\pm}$2.7) months. The half life of PSA Of the nonfailing patients was 2.1 (${\pm}$0.9) month. The nadir PSA level Of the nonfailing Patients waS 0.8 (${\pm}$0.5) ng/ml. The period of PSA normalization had the positive correlation with pretreatment PSA level (R$^{2}$=0.468). The nadir PSA level had no definite positive correlation with the pretreatment PSA level (R$^{2}$=0.075). The half life of serum PSA level also had no definite correlation with pretreatment PSA level (R$^{2}$=0.029). Conclusion :The PSA level was mostly normalized within 8 months (85%). If it has not normalized within 12 months, we should consider the residual disease in prostate or distant metastasis. In 2 patients, the PSA level increased 6 months or 20 months before clinical disease was detected. So the serum PSA level can be used as early diagnostic indicator of treatment failure.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.194-201
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• 2015

We have investigated the EPR signal properties in 12 components of two mobile phones (LCD, OLED) using electron paramagnetic resonance (EPR) spectrometer in this study.EPR measurements were performed at normal atmospheric conditions using Bruker EXEXSYS-II E500 spectrometer with X-band bridge, and samples were irradiated by $^{137}Cs$ gamma-ray source. To identify the presence of radiation-induced signal (RIS), the EPR spectra of each sample were measured unirradiated and irradiated at 50 Gy. Then, dose-response curve and signal intensity variating by time after irradiation were measured. As a result, the signal intensity increased after irradiation in all samples except the USIM plastic and IC chip. Among the samples, cover glass(CG), lens, light guide plate(LGP) and diffusion sheet have shown fine linearity ($R^2$ > 0.99). Especially, the LGP had ideal characteristics for dosimetry because there were no signal in 0 Gy and high rate of increase in RIS. However, this sample showed weakness in fading. Signal intensity of LGP and Diffusion Sheet decreased by 50% within 72 hours after irradiation, while signals of Cover Glass and Lens were stably preserved during the short period of time. In order to apply rapidly EPR dosimetry using mobile phone components in large-scale radiation accidents, further studies on signal differences for same components of the different mobile phone, fading, pretreatment of samples and processing of background signal are needed. However, it will be possible to do dosimetry by dose-additive method or comparative method using unirradiated same product in small-scale accident.