• 방사선산업학회지
• /
• 제5권2호
• /
• pp.145-149
• /
• 2011

Poly(butylenes terephthalate) have made large strides in applications of injection, extrusion, and molding material due to their excellent thermal resistance and appropriate mechanical properties. However, PBT was not hard polymer but a soft polymer which caused low absorption of external energy and the defect of being easily broken with the strong impact. Thus, the electron beam irradiation was carried out over a range of irradiation doses from 100 to 1,000 kGy for enhancing the properties. The decreases of $T_m$, $T_c$, and enthalpy were observed as increasing the absorbed dose in the results of DSC analysis. The improvement in the impact strength of PBT was clearly observed as the absorbed dose was increased. This was probably due to the 3-dimensional network structures, resulting in increasing the absorption of impact energy. In addition, the wear properties had increased at higher than 300 kGy. The negative deviation of weight loss confirmed the improvement of the wear properties of PBT, as evidenced by SEM observation on the wear surfaces.

• Radiation Oncology Journal
• /
• 제7권2호
• /
• pp.197-203
• /
• 1989

1969년부터 1983년까지 버지니아 의대부속병원에서 방사선 치료를 받은 34예의 원발성 척수암중, 조직검사 또는 아절제술을 시행한 후 수술후 방사선 요법으로 치료받은 32예 (Astrocytoma 16, ependymoma 16)에 대한 치료실적을 보고하고자 한다. 29예에서는 $45\~55Gy$를 5내지 6주간에 조사 받았으며 나머지 3예에서는 40Gy이하의 선량을 조사받았다. 50Gy 이상 조사된 6예는 모두 척수가 조사야에 포함되었다. 본 연구의 최저 추적 기간은 5년이었다. 방사선 치료 실패 후 재수술로 치료된 3예를 포함하여, 모든 예에서 생존율은 5년과 10년에서 각각 $73\%\;와\;50\%$이었다. 각각의 투병생존율은 $60\%\;와\;32\%$이었다. 45Gy 이상의 선량을 받은 29예에서는 5년 무병생존이 $63\%$이었다. 13예에서 치료실패를 경험했으며 치료실패는 조사야에서만 관찰되었다. Ependymoma가 astrocytoma보다 통계적으로 유의하게 무병생존율이 높았다 $(45\%\;:\; 89\%(p<0.05))$, 원발부위에 있어 경추가 포함된 예에서 그렇지 않은 예보다 생존율이 저하되었다. 원발부위의 cauda equina포함여부는 예후에 영향이 없었다. 최고 20년간 추적결과 방사선 치료에 의한 신경성 합병증은 관찰되지 않았다. 본 연구는 원발성 척수암의 치료에 있어서 방사선 치료가 안전하고 효과적임을 확인하였다.

• Radiation Oncology Journal
• /
• 제31권3호
• /
• pp.162-170
• /
• 2013

Purpose: To analyze the outcome of adjuvant postoperative external beam radiotherapy (EBRT) in well-differentiated thyroid cancer (WDTC). Materials and Methods: We identified 84 patients treated with EBRT for WDTC from February 1981 to December 2010. Among them, we analyzed 39 patients who received EBRT after initial radical surgery. Twenty-four females and 15 males were included. The median age was 49 years (range, 16 to 72 years). There were 34 papillary thyroid carcinomas and 5 follicular thyroid carcinomas. Most patients showed pathologic T3/T4 stage (54%/26%). Ten patients (25.6%) had gross residual tumors. Five patients (12.8%) had tumor cells at the margin. The median EBRT dose and fraction size were 62.6 Gy and 1.8 to 2.0 Gy, respectively. Results: The median follow-up was 73 months (range, 21 to 372 months). The five-year overall survival (OS) and locoregional recurrence free survival (LRFS) were 97.4% and 86.9%, respectively. Locoregional failures occurred in 5 and all failure sites were the neck node area. In univariate analysis, OS was significantly influenced by invasion of the trachea (p = 0.016) or esophagus (p = 0.006). LRFS was significantly decreased by male (p = 0.020), gross residuum after resection (p = 0.002), close or positive tumor at surgical margin involvement (p = 0.044), and tracheal invasion (p = 0.040). No significant prognostic factor was identified in the multivariate analysis. No patient experienced the Radiation Therapy Oncology Group grade 3 or more toxicity. Conclusion: Our locoregional control rate of 87.2% is comparable to historical controls with surgery alone, even though our study had a large proportion of advanced stage. Adjuvant EBRT may an effective and safe treatment option in patients with WDTC.

• The Korean Journal of Pain
• /
• 제26권3호
• /
• pp.223-241
• /
• 2013

Boney metastasis may lead to terrible suffering from debilitating pain. The most likely malignancies that spread to bone are prostate, breast, and lung. Painful osseous metastases are typically associated with multiple episodes of breakthrough pain which may occur with activities of daily living, weight bearing, lifting, coughing, and sneezing. Almost half of these breakthrough pain episodes are rapid in onset and short in duration and 44% of episodes are unpredictable. Treatment strategies include: analgesic approaches with "triple opioid therapy", bisphosphonates, chemotherapeutic agents, hormonal therapy, interventional and surgical approaches, steroids, radiation (external beam radiation, radiopharmaceuticals), ablative techniques (radiofrequency ablation, cryoablation), and intrathecal analgesics.

• 천문학회지
• /
• 제25권2호
• /
• pp.111-128
• /
• 1992

Infrared emissions from spherical dust, clouds are calculated using quasi-diffusion method. We have employed graphite-silicate mixture with power-law size distribution for the dust model. The grains are assumed to be heated and cooled by radiative processes only. The primary heating source is diffuse interstellar radiation field. hut the cases with an embedded source are also considered. Since graphite grains have higher temperature than silicate grains, the observed IR emission is mainly due to graphite grains, unless the fraction of graphite grains is negligibly small. The color temperature of Bok globules obtained from IRAS 60 and $100{\mu}m$ data are found to be consistent with the dust cloud with graphite-silicate mixture exposed to average interstellar radiation field. The color temperature is sensitive to the external radiation field, but rather insensitive to the size distribution of the grains. We found that the density distribution can be recovered outside the beam size using the inversion technique that assumes negligible optical depth. However, the information within the beam size is lost for if beam convolved intensity distributions are used in deriving density profile.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권12호
• /
• pp.6251-6255
• /
• 2012

Radiation proctitis and radiation cystitis are major complications for patients with cervical carcinoma following radiotherapy. In the present study, we aimed to determine the potential risk factors for the development of radiation proctitis and radiation cystitis after irradiation. A total of 1,518 patients with cervical carcinoma received external beam radiotherapy (EBRT) followed by high-dose-rate intracavitary brachytherapy (HDRICB) in our hospital. The incidences of radiation proctitis and radiation cystitis were recorded and associations with different factors (age, time period, tumor stage) were analyzed with ${\chi}^2$ (chi-squared) and Fisher exact tests. We found that 161 and 94 patients with cervical carcinoma were diagnosed with radiation proctitis and radiation cystitis, respectively, following radiotherapy. The prevalence of Grade I-II radiation proctitis or radiation cystitis was significantly lower than that of Grade III (radiation proctitis: 3.82% vs. 6.76%, P < 0.05; radiation cystitis: 2.31% vs. 3.87%, P < 0.05) and was significantly enhanced in patients with late stage (IIIb) tumor progression compared to those in early stage (Ib, IIa) (P < 0.05). Moreover, the incidence of radiation proctitis and cystitis was not correlated with age or, time period following radiation, for each patient (P > 0.05). These observations indicate that a late stage of tumor progression is a potential risk factor for the incidence of radiation proctitis and cystitis in cervical carcinoma patients receiving radiotherapy.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권10호
• /
• pp.4577-4581
• /
• 2016

Objective: The aim of this study was to assess thyroid function in breast cancer patients exposed to therapeutic external beam radiation. The focus was on possible progressive changes and any relationships between the incidence of primary hypothyroidism, the time required to become hypothyroid, and factors such as chemotherapy, hormonotherapy and immunotherapy. Materials and Methods: Seventy females undergoing 3D conformal and IMRT radiation therapy for breast cancers were enrolled in a non-randomized prospective study. The patients was divided into two groups: those after mastectomy or breast conserving surgery (BCS) were irradiated to a scar of the chest wall/breast and the ipsilateral supraclavicular and the axillary areas (supraclavicular radiotherapy group - SC-RT group - 32 patients) and the control group receiving adjuvant chest wall/breast RT only (BCT group - 38 patients).The total doses were 50.0 to 70 Gy in 5 to 7 weeks. The median follow-up term was 24 months (range, 1-40 months). Thyroid function was evaluated by measuring thyroid stimulating hormone (TSH), free thyroxine (fT4), and free triiodothyronine (fT3) levels. The minimum, maximum and mean thyroid gland doses for 20 Gy (V20) were calculated for all patients. Results: Statistically significant results were obtained for the SC-RT group. Two yearsa fter the end of RT the chance of an event was increased in 6% of the population (p=0.009) in the SC-RT group. In the BCT group no significance was noted. No statistically significant differences were found for V20, chemio-, immunotherapy and hormonotherapy or Ki67 values (p=0.12). No significant results were obtained for development of hypothyroidism and clinical factors (age, thyroid volume, treatment modalities). Conclusion: Radiotherapy is associated with a higher incidence of thyroid toxicity in breast cancer patients. Routine thyroid function monitoring should be recommended in such cases.

• Radiation Oncology Journal
• /
• 제15권3호
• /
• pp.251-254
• /
• 1997

목적 : 침윤성자궁경부암에서 단순자궁적출술을 시행하는 것은 통상적인 치료원칙에 배치된다. 본 연구는 침윤성자궁경부암에서 단순자궁적출술이 시행되었을 경우 방사선치료의 역할을 확인하기 위하여 시행되었다. 대상 및 방법 :침윤성자궁경부암환자로서 단순자궁적출을 시행받고 1989년 4월부터 1993년 12월까지 경상대학교병원 치료방사선과에서 방사선치료를 시행받은 19명의 환자를 대상으로 후향적 분석을 시행하였다. 연구대상의 연령의 중앙값은 49세이었고, 연구대상에 대한 추적기간의 중앙간은 46개월이었다. 방사선치료는 17명에서는 외부방사선조사만 시행되었고 절제연에 잔류암이 있었던 2명에서는 강내치료를 병용하였다. 결과 : 전체 4년 생존율은 $75\%$이었고, 4년 국소제어율은 $89\%$이었다. 2명에서 국소 및 원격재발이 있었고 2명에서 원격재발이 있었다. 결론 : 침윤성 자궁경부암에서 단순자궁적출술이 시행된 경우 방사선치료는 매우 적절한 후속조치가 됨을 확인할 수 있었다.

• 대한방사선치료학회지
• /
• 제3권1호
• /
• pp.11-18
• /
• 1989

Brachytherapy is known to be a good modality to achieve local control as a boost treatment following limited external irradiation, which may reduce the external beam related complication particularly in head and neck cancer. The authors developed iridium-192 ribbons recently to replace the radium needles in the field of brachytherapy. Total of 48 cases of head and neck and pelvic-perineal cancer patients had been treated with Ir-192 ribbons during last two years from October 1986 to September 1988, and the results were analyzed to assess the applicability of the fabricated sources. The conclusion is as follows; 1. Iridium implant resulted excellent tumor control effect in clinical application. 2. Iridium is superior than radium and cecium in brachytherapy because of easier to use and lesser exposure to the personnel. 3. Afterloading technique is useful to modify dose distribution, to expand treatment site and method, and to develop interstitial hyperthermia.

• Radiation Oncology Journal
• /
• 제36권2호
• /
• pp.147-152
• /
• 2018

Purpose: To evaluate the treatment outcomes of adjuvant external beam radiation therapy (EBRT) and vaginal brachytherapy (VB) following radical hysterectomy in cervical cancer patients with involved vaginal resection margin (VRM). Materials and Methods: We retrospectively reviewed the medical records of 21 patients treated with postoperative EBRT and VB for positive VRM FIGO stage IB-IIA cervical cancer between 2003 and 2015. Concurrent platinum-based chemotherapy was administered to all patients. Results: The median whole pelvis EBRT dose was 50.4 Gy (range, 45 to 50.4 Gy). In the VB, the median dose per fraction, number of fractions, and total dose delivered were: 4 Gy (range, 3.0 to 4.0 Gy), 4 fractions (range, 3 to 5 fractions), and 16 Gy (range, 12 to 20 Gy), respectively. At a median follow-up of 46 months (range, 9 to 122 months), local recurrence was observed in 2 patients, and distant metastasis was present in 7 patients. All patients with local recurrence subsequently developed distant metastases. The 5-year local control, disease-free survival, and overall survival rates were 89.1%, 65.9%, and 62.9%, respectively. Of the 21 patients, 7 patients (33.3%) reported grade 2 acute toxicity; however, there were no grade 3 or higher acute adverse events. Grade 1-2 late toxicities were observed in 8 patients. Late grade 3 urinary toxicity was reported in 1 patient. Conclusions: Adjuvant EBRT and VB showed excellent local control and low toxicity in cervical cancer patients with positive VRM. Although limited by its retrospective nature, the findings from our study provide evidence supporting the use of additional VB in pathologically involved VRM.