• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.1713-1718
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• 2012

Advanced imaging approaches (computed tomography, CT; magnetic resonance imaging, MRI; $^{18}F$-fluorodeoxyglucose positron emission tomography, FDG PET) have increased roles in cervical cancer staging and management. The recent FIGO (International Federation of Gynecology and Obstetrics) recommendations encouraged applications to assess the clinical extension of tumors rather than relying on clinical examinations and traditional non-cross sectional investigations. MRI appears to be better than CT for primary tumors and adjacent soft tissue involvement in the pelvis. FDG-PET/CT has increased in usage with a particular benefit for whole body evaluation of tumor metabolic activity. The potential benefits of advanced imaging are assisting selection of treatment based upon actual disease extent, to adequately treat a tumor with minimal normal tissue complications, and to predict the treatment outcomes. Furthermore, sophisticated external radiation treatment and brachytherapy absolutely require advanced imaging for target localization and radiation dose calculation.

• Progress in Medical Physics
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• v.29 no.1
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• pp.23-28
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• 2018

The purpose of this study is to build a database of patient information for efficient radiotherapy management. Microsoft Office Access was used to build the database owing to its convenience and compatibility. The most important aspect when building the patient database is to make the input and management of patient information efficient at every step of radiotherapy process. The information input starts from the patient's first visit to the radiation therapy department and ends upon completion of the radiotherapy. The forms for each step of radiotherapy process include the patient information form, the radiotherapy schedule form, the radiotherapy information form, the simulation order form, and the patient history form. Every form is centrically connected to the radiation oncology department's patient information form. A test revealed that the database was found to be efficient in managing patient information at each step. An important benefit of this database is improved efficiency in radiotherapy management. Information on patients who received radiotherapy is stored in a database. This means that this clinical data can be found easily and used in future, which will be helpful in research studies on the radiation oncology department. Benefits such as these will potentially contribute to improved radiotherapy quality.

• Radiation Oncology Journal
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• v.37 no.3
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• pp.185-192
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• 2019

Purpose: The effectiveness of thoracic radiation therapy (TRT) in extensive-stage small cell lung cancer (ES-SCLC) patients is increasingly reported, but there is no definite consensus on its application. The aim of this study was to identify factors associated with better outcomes of TRT among patients with ES-SCLC, focusing on whether a higher TRT dose could improve treatment outcome. Materials and Methods: The medical records of 85 patients with ES-SCLC who received TRT between January 2008 and June 2017 were retrospectively reviewed. Eligibility criteria were a biological effective dose with α/β = 10 (BED) higher than 30 Gy₁₀ and completion of planned radiotherapy. Results: During a median follow-up of 5.3 months, 68 patients (80.0%) experienced disease progression. In univariate analysis, a BED >50 Gy₁₀ was a significant prognostic factor for overall survival (OS; 40.8% vs. 12.5%, p = 0.006), progression-free survival (PFS; 15.9% vs. 9.6%, p = 0.004), and intrathoracic PFS (IT-PFS; 39.3% vs. 20.5%, p = 0.004) at 1 year. In multivariate analysis, a BED >50 Gy₁₀ remained a significant prognostic factor for OS (hazard ratio [HR] = 0.502; 95% confidence interval [CI], 0.287-0.876; p = 0.015), PFS (HR = 0.453; 95% CI, 0.265-0.773; p = 0.004), and IT-PFS (HR = 0.331; 95% CI, 0.171-0.641; p = 0.001). Response to the last chemotherapy was also associated with better OS in both univariate and multivariate analysis. Conclusion: A TRT dose of BED >50 Gy₁₀ may be beneficial for patients with ES-SCLC. Further studies are needed to select patients who will most benefit from high-dose TRT.

• Imaging Science in Dentistry
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• v.43 no.3
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• pp.179-184
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• 2013

Purpose: X-ray exposure should be clinically justified and each exposure should be expected to give patients benefits. Since dental radiographic examination is one of the most frequent radiological procedures, radiation hazard becomes an important public health concern. The purpose of this study was to investigate the attitude of Korean dentists about radiation safety and use of criteria for selecting the frequency and type of radiographic examinations. Materials and Methods: The study included 267 Korean dentists. Five questions related to radiation safety were asked of each of them. These questions were about factors associated with radiation protection of patients and operators including the use of radiographic selection criteria for intraoral radiographic procedures. Results: The frequency of prescription of routine radiographic examination (an example is a panoramic radiograph for screening process for occult disease) was 34.1%, while that of selective radiography was 64.0%. Dentists' discussion of radiation risk and benefit with patients was infrequent. More than half of the operators held the image receptor by themselves during intraoral radiographic examinations. Lead apron/thyroid collars for patient protection were used by fewer than 22% of dental offices. Rectangular collimation was utilized by fewer than 15% of dental offices. Conclusion: The majority of Korean dentists in the study did not practice radiation protection procedures which would be required to minimize exposure to unnecessary radiation for patients and dental professionals. Mandatory continuing professional education in radiation safety and development of Korean radiographic selection criteria is recommended.

• Radiation Oncology Journal
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• v.34 no.3
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• pp.202-208
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• 2016

Purpose: Our institution has implemented two different adjuvant protocols in treating patients with non-small cell lung cancer (NSCLC): chemotherapy followed by concurrent chemoradiotherapy (CT-CCRT) and sequential postoperative radiotherapy (PORT) followed by postoperative chemotherapy (POCT). We aimed to compare the clinical outcomes between the two adjuvant protocols. Materials and Methods: From March 1997 to October 2012, 68 patients were treated with CT-CCRT (n = 25) and sequential PORT followed by POCT (RT-CT; n = 43). The CT-CCRT protocol consisted of 2 cycles of cisplatin-based POCT followed by PORT concurrently with 2 cycles of POCT. The RT-CT protocol consisted of PORT followed by 4 cycles of cisplatin-based POCT. PORT was administered using conventional fractionation with a dose of 50.4-60 Gy. We compared the outcomes between the two adjuvant protocols and analyzed the clinical factors affecting survivals. Results: Median follow-up time was 43.9 months (range, 3.2 to 74.0 months), and the 5-year overall survival (OS), locoregional recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were 53.9%, 68.2%, and 51.0%, respectively. There were no significant differences in OS (p = 0.074), LRFS (p = 0.094), and DMFS (p = 0.490) between the two protocols. In multivariable analyses, adjuvant protocol remained as a significant prognostic factor for LRFS, favouring CT-CCRT (hazard ratio [HR] = 3.506, p = 0.046) over RT-CT, not for OS (HR = 0.647, p = 0.229). Conclusion: CT-CCRT protocol increased LRFS more than RT-CT protocol in patients with completely resected NSCLC, but not in OS. Further studies are warranted to evaluate the benefit of CCRT strategy compared with sequential strategy.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.214-227
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• 2013

Computed tomographic scan as a screening procedures in asymptomatic individuals has seen a steady increase with the introduction of multiple-raw detector CT scanners. This report provides a brief review of the current controversy surrounding CT cancer screening, with a focus on the radiation induced cancer risks and clinical efficacy. 1. A large study of patients at high risk of lung cancer(the National Lung Screening Trial[NLST]) showed that CT screening reduced cancer deaths by 20%(1.33% in those screened compared with 1.67% in those not screened). The rate of positive screening tests was 24.2% and 96.4% of the positive screening results in the low-dose CT group were false-positive. Radiation induced lung cancer risk was estimated the most important in screening population because ERR of radiation induced lung cancer does not show the decrease with increasing age and synergistic connection between smoking and radiation risk. Therefore, the radiation risk may be on the same order of magnitude as the benefit observed in the NLST. Optimal screening strategy remain uncertain, CT lung cancer screening is not yet ready for implementation. 2. Computed tomographic colonography is as good as colonoscopy for detecting colon cancer and is almost as good as colonoscopy for detecting advanced adenomas, but significantly less sensitive and specific for smaller lesions and disadvantageous for subsequent therapeutic optical colonoscopy if polyps are detected. The average effective dose from CT colonography was estimated 8-10 $mS{\nu}$, which could be a significant dose if administered routinely within the population over many years. CT colonography should a) achieve at least 90% sensitivity and specificity in the size category from 6 and 10 mm, b) offer non-cathartic bowl preparation and c) be optimized and standardized CT parameters if it is to be used for mass screening. 3. There is little evidence that demonstrates, for whole-body scanning, the benefit outweighs the detriment. This test found large portion of patient(86~90.8%) had at least one abnormal finding, whereas only 2% were estimated to have clinically significant disease. Annual scans from ages 45 to 75 years would accrue an estimated lifetime cancer mortality risk of 1.9%. There is no group within the medical community that recommends whole-body CT. No good studies indicate the accuracy of screening CT, at this time. The benefit/risk balance for any of the commonly suggested CT screening techniques has yet to be established. These areas need further research. Therefore wild screening should be avoided.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5557-5563
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• 2014

Background: This study investigated the survival benefit of radiotherapy (RT) of the supra- and infraclavicular lymphatic drainage area in Chinese women with T1-2N1M0 breast cancer receiving mastectomy. Methods: A total of 593 cases were retrospectively reviewed from 1998 to 2007. The relationship between supra- or infraclavicular fossa relapse (SCFR) and post-operative RT at the supra-/infraclavicular lymphatic drainage area was evaluated. Results: The majority of patients (532/593; 89. 8%) received no RT while 61 patients received RT. The median follow-up was 85 months. Among patients without RT, 54 (10. 2%) developed recurrence in the chest wall or ipsilateral SCFR. However, none of the 61 patients who underwent RT demonstrated SCFR. One patient who received RT (1. 6%) experienced recurrence in the chest wall. Univariate analysis revealed that age and molecular subtype (both P < 0. 05) were two prognostic factors related to supraclavicular and infraclavicular fossa relapse-free survival (SFRFS). Multivariate analysis revealed that only Her-2 positive status (P = 0. 011) was an independent predictor of SFRFS. RT had no influence on distant metastasis (P = 0. 328) or overall survival (P = 0. 541). SCFR significantly affected probability of distant metastasis (P < 0. 001) and overall survival (P < 0. 001). Conclusion: Although RT was not significantly associated with SFRFS, postoperative RT was significantly associated with a lower locoregional (i. e., supraclavicular/infraclavicular and chest wall) recurrence rate. SCFR significantly influenced distant metastasis-free survival, which significantly influenced the overall survival of T1-2N1M0 breast cancer patients after mastectomy. Thus, prophylactic RT is recommended in T1-2N1M0 breast cancer patients, especially those who have Her-2 positive lesions.

• Radiation Oncology Journal
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• v.32 no.4
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• pp.247-255
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• 2014

Purpose: To determine whether neoadjuvant androgen deprivation therapy (NADT) improves clinical outcomes in patients with prostate cancer treated with definitive radiotherapy. Materials and Methods: We retrospectively reviewed medical records of 201 patients with prostate cancer treated with radiotherapy between January 1991 and December 2008. Of these, 156 patients with more than 3 years of follow-up were the subjects of this study. The median duration of follow-up was 91.2 months. NADT was given in 103 patients (66%) with median duration of 3.3 months (range, 1.0 to 7.7 months). Radiation dose was escalated gradually from 64 Gy to 81 Gy using intensity-modulated radiotherapy technique. Results: Biochemical relapse-free survival (BCRFS) and overall survival (OS) of all patients were 72.6% and 90.7% at 5 years, respectively. BCRFS and OS of NADT group were 79.5% and 89.8% at 5 years and those of radiotherapy alone group were 58.8% and 92.3% at 5 years, respectively. Risk group (p = 0.010) and radiation dose ${\geq}70Gy$ (p = 0.017) affected BCRFS independently. NADT was a significant prognostic factor in univariate analysis, but not in multivariate analysis (p = 0.073). Radiation dose ${\geq}70Gy$ was only an independent factor for OS (p = 0.007; hazard ratio, 0.261; 95% confidence interval, 0.071-0.963). Conclusion: NADT prior to definitive radiotherapy did not result in significant benefit in terms of BCRFS and OS. NADT should not be performed routinely in the era of dose-escalated radiotherapy.

• Journal of Chest Surgery
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• v.25 no.9
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• pp.962-967
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• 1992

Eight patients with proven clinical stage Ill lung carcinoma of which six were epidermoid cell carcinoma and two were small cell carcinoma underwent concomitant radiation therapy and chemotherapy before surgical resection from March 1990 to February 1992 at the thoracic surgical department, Yongdong Severance Hospital, Yonsei University College Medicine The therapy consisted of more than one cycle of chemotherapy every 4 weeks and concomitant irradiation. Three to four weeks after chemotherapy and radiation therapy, the patient were reevaluated for thoracotomy and pulmonary resection. Two patients were found to have unresectable lesions and, radiosotopes were implanted to the remaining tumors. Three patients had complete pneumonectomies and two patients had pericardial penumonectomyo. Only one patient had complete pneumonectomy & concomitant resection of ribs attached to tumors with reconstruction of chest wall with Marlex mesh. Complete sterilization of lung tumor and mediastinal nodes proven histologically was achieved in 2 patients, without operative mortality. The median survival of all patients was eight months, but the median survival of survivors which lung tumor were completely resected completely and whose pathologic reports showed stage I or 0, was about 18 months to now. The overall result indicates some benefit from this preoperative chemotherapy and radiation therapeutic regimen in patients with advanced unresectable lung cancer.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2339-2345
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• 2020

Radiation imaging systems consisting of a large number of channels greatly benefit from multiplexing methods to reduce the number of channels with minimizing the system complexity and development cost. In conventional pixelated radiation detector modules, such as anger logic, is used to reduce a large number of channels that transmit signals to a data acquisition system. However, these methods have limitations of electrical noise and distortion at the detector edge. To solve these problems, a multiplexing concept using a digital signal encoding technique based on a time delay method for signals from detectors was developed in this study. The digital encoding multiplexing (DEM) method was developed based on the time-over-threshold (ToT) method to provide more information including the activation time, position, and energy in one-bit line. This is the major advantage of the DEM method as compared with the traditional ToT method providing only energy information. The energy was measured and calibrated by the ToT method. The energy resolution and coincidence time resolution were observed as 16% and 2.4 ns, respectively, with DEM. The position was successfully distributed on each channel. This study demonstrated the feasibility that DEM was useful to reduce the number of detector channels.