• Radiation Oncology Journal
• /
• v.36 no.4
• /
• pp.304-316
• /
• 2018

Purpose: The indication of elective neck treatment (ENT) for clinically N0 (cN0) paranasal sinus (PNS) carcinoma remains unclear. We aimed to investigate different treatment outcomes regarding ENT and propose optimal recommendations for ENT. Materials and Methods: We identified patients with cN0 PNS carcinoma who underwent curative-intent treatment between 1992 and 2015. Survival outcomes and pattern of failure were compared between patients who received ENT and those who did not. We sought to identify significant patient or pathologic factors regarding treatment outcomes. Results: Among 124 patients meeting the inclusion criteria, 40 (32%) received ENT ('ENT (+) group') and 84 (68%) did not ('ENT (-) group'). With a median follow-up of 54 months, the 5-year overall survival (OS) was 67%, and the 5-year progression-free survival (PFS) was 45%. There was no significant difference between the ENT (+) and ENT (-) groups regarding OS (p = 0.67) and PFS (p = 0.50). Neither group showed a significantly different pattern of failure, including regional failure (p = 0.91). There was no specific benefit, even in the subgroups analysis by tumor site, histologic type, and T stage. Nevertheless, patients who ever had regional and/or distant failure showed significantly worse prognosis. Conclusion: ENT did not significantly affect the survival outcome or pattern of failure in patients with cN0 PNS carcinomas, showing that ENT should not be generalized in this group. However, further discussion on the optimal strategy for ENT should continue because of the non-negligible regional failure rates and significantly worse prognosis after regional failure events.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2002.09a
• /
• pp.305-308
• /
• 2002

More complex radiotherapy techniques using multi leaf collimation(MLC) such as intensity-modulated radiation therapy(IMRT) has been increasing the significance of verification of leaf position and motion. Due to the reliability and robustness, quality assurance(QA) of MLC is usually performed with portal films. However, the advantage of ease of use and capability of providing digital data of electronic portal imaging devices(EPIDs) have attracted many attentions as alternatives of films for routine quality assurance in spite of the concerns about their clinical feasibility, efficacy, and the cost to benefit ratio. In our work, the method of routine QA of MLC using electronic portal imaging(EPI) was developed. The verification of availability of EPI images for routine QA was performed by comparison with those of the portal films which were simultaneously obtained when radiation was delivered and known prescription input to MLC controller. Specially designed test patterns of dynamic MLC were applied to image acquisition. Quantitative off-line analysis using edge detection algorithm enhanced the verification procedure in addition to on-line qualitative visual assessment. In conclusion, the EPI is available enough for routine QA with the accuracy of portal films.

• Radiation Oncology Journal
• /
• v.35 no.4
• /
• pp.359-367
• /
• 2017

Purpose: This study sought to identify potential candidates for adjuvant radiotherapy and patterns of regional failure in patients who underwent curative-intent surgery for gallbladder cancer. Materials and Methods: Records for 70 patients with gallbladder cancer who underwent curative resection at a single institution between 2000 and 2016 were analysed retrospectively. No patients received adjuvant radiotherapy. Initial patterns of failure were evaluated. Regional recurrence was categorized according to the definitions of lymph node stations suggested by the Japanese Society of Hepato-Biliary-Pancreatic Surgery. Results: Median follow-up was 23 months. Locoregional recurrence as any component of first failure occurred in 29 patients (41.4%), with isolated locoregional recurrence in 13 (18.6%). Regional recurrence occurred in 23 patients, and 77 regional recurrences were identified. Commonly involved regional stations were #13, #12a2, #12p2, #12b2, #16a2, #16b1, #9, and #8. Independent prognostic factors for locoregional recurrence were ${\geq}pT2$ disease (hazard ratio [HR], 5.510; 95% confidence interval [CI], 1.260-24.094; p = 0.023) and R1 resection (HR, 6.981; 95% CI, 2.378-20.491; p < 0.001). Conclusion: Patients with pT2 disease or R1 resection after curative surgery for gallbladder cancer may benefit from adjuvant radiotherapy. Our findings on regional recurrence may help physicians construct a target volume for adjuvant radiotherapy.

• Journal of Environmental Health Sciences
• /
• v.50 no.1
• /
• pp.1-5
• /
• 2024

International Commission on Radiological Protection (ICRP) is an independent international organization that advances the science of radiological protection for the public benefit, particularly by providing recommendations and guidance on all aspects of protection against ionizing radiation. The ICRP is a community of more than 380 globally-recognized experts in radiological protection science, policy, and practice from more than 50 countries. As of January 2024, the ICRP is comprised of a Main Commission, the Scientific Secretariat, four Standing Committees, and 30 Task Groups under the four committees. The ICRP has released well over one hundred publications on all aspects of radiological protection. Most address a particular area within radiological protection, but a handful of the publications, the so-called fundamental recommendations, describe the overall system of radiological protection. The system for radiological protection is based on the current understanding of the science of radiation exposure and its effects along with value judgements. The ICRP offers recommendations to regulatory and advisory agencies and provides advice to management and professional staff with responsibilities for radiological protection. Legislation in most countries adheres closely to ICRP recommendations. The International Atomic Energy Agency's (IAEA) International Basic Safety Standards are based heavily on ICRP recommendations. ICRP recommendations form the core of radiological protection standards, legislation, programs, and practice worldwide.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.7
• /
• pp.2915-2921
• /
• 2015

Background: Some recent clinical trials have been conducted to evaluate a combination of EGFR- TKI with chemotherapy for advanced NSCLC patients as second-line therapy, but the results on the efficacy of such trials are inconsistent. The aim of this meta-analysis was to evaluate the efficacy and safety of combination of EGFR-TKI and chemotherapy for patients with advanced NSCLC who failed first-line treatment. Materials and Methods: We searched relative trials from PubMed, EMBASE, ASCO Abstracts, ESMO Abstracts, Cochrane Library and Clinical Trials.gov. Outcomes analyzed were overall response rate (ORR), progression- free survival (PFS), overall survival (OS) and major toxicity. Results: Seven trails eventually were included in this meta-analysis, covering 1,168 patients. The results showed that the combined regimen arm had a significant higher ORR (RR 1.76 [1.16, 2.66], p=0.007) and longer PFS (HR 0.75 [0.66-0.85], p<0.00001), but failed to show effects on OS (HR 0.88 [0.68-1.15], p=0.36). In terms of subgroup results, continuation of EGFR-TKI in addition to chemotherapy after first-line EGFR-TKI resistance confered no improvement in ORR (RR 0.95 [0.68, 1.33], p=0.75) and PFS (HR 0.89[0.69, 1.15], p=0.38), and OS was even shorter (HR1.52 [1.05-2.21], p=0.03). However, combination therapy with EGFR-TKI and chemotherapy after failure of first-line chemotherapy significantly improved the ORR (RR 2.06 [1.42, 2.99], p=0.0002), PFS (HR 0.71 [0.61, 0.82], p<0.00001) and OS (HR 0.74 [0.62-0.88], p=0.0008), clinical benefit being restricted to combining EGFR-TKI with pemetrexed, but not docetaxel. Grade 3-4 toxicity was found at significantly higher incidence in the combined regimen arm. Conclusions: Continuation of EGFR-TKI in addition to chemotherapy after first-line EGFR-TKI resistance should be avoided. Combination therapy of EGFR-TKI and pemetrexed for advanced NSCLC should be further investigated for prognostic and predictive factors to find the group with the highest benefit of the combination strategy.

• Journal of Korean Neurosurgical Society
• /
• v.54 no.3
• /
• pp.175-182
• /
• 2013

Objective : Intracavitary injection of beta-emitting radiation source for control of cystic tumors has been tried with a benefit of localized internal radiation. The authors treated cystic brain tumor patients with Holmium-166-chitosan complex (Ho-166-chico), composed of a beta-emitting radionuclide Holmium-166 and biodegradable chit polymer, and evaluated the safety and effective measurement for response. Methods : Twenty-two patients with recurrent cystic brain tumor and/or located in a deep or eloquent area were enrolled in this pilot study. The cyst volume and wall thickness were determined on CT or MRI to assess radiological response. The activity of Ho-166-chico injected via Ommaya reservoir was prescribed to be 10-25 Gy to the cyst wall in a depth of 4 mm. Results : There was neither complications related to systemic absorption nor leakage of Ho-166-chico in all 22 patients. But, two cases of oculomotor paresis were observed in patients with recurrent craniopharyngioma. Radiological response was seen in 14 of 20 available follow-up images (70%). Seven patients of 'evident' radiological response experienced more than 25% decrease of both cyst volume and wall thickness. Another 7 patients with 'suggestive' response showed decrease of cyst volume without definitive change of the wall thickness or vice versa. All patients with benign tumors or low grade gliomas experienced symptomatic improvement. Conclusion : Ho-166-chico intracavitary radiation therapy for cystic tumor is a safe method of palliation without serious complications. The determination of both minimal effective dosage and time interval of repeated injection through phase 1 trial could improve the results in the future.

• The Journal of the Korean dental association
• /
• v.52 no.3
• /
• pp.153-163
• /
• 2014

3-dimensional information for anatomic stucture plays a role as integral part in clinical aspect of dental practice. CBCT(cone beam computed tomography) has been accepted as useful diagnostic tool offering Volume data and images for evaluating teeth and jaws in lower radiation dose than conventional CT. CBCT equipment is essential for the quality assurance of it to ensure continued satisfactory performance and result of adequate images. Dental practitioner and oral and maxillofacial radiologist should have a responsibility and critical thinking to deliver this technology to patients in a responsible way, so that diaganostic value is maximised and radiation doses kept as low as resonably achievable. CBCT imaging modality should be used only after a review of the patient's health and imaging history and the completion of a thorough clinical examination. Clinical guidelines are systematically developed statements to assist practitioner and patient decisions about appropriate health care for specific clinical circumstances Dental practitioners should prescribe CBCT imaging only when they expect that the diagnostic yield will benefit patient care, enhance patient safety or improve clinical outcomes significantly. Knowledge of patient dose is essential for clinicians who are making the decision regarding the justification of the exposure. There are some limitation in the measurement of patient dose in CBCT for the approval and adaptation of conventinal methodolgy in CT. It is also important to ensure that doses are optimised and in line with any national and international guidelines. The higher radiation doses of CBCT compared with conventional radiography, mean that high standards must be maintained. The Quality Assurance(QA) programme should entail surveys and checks that are performed according to a regular timetable. QA programme should be maintained by staff to ensure adherence to the programme and to raise its importance among staff.

• Journal of Radiation Protection and Research
• /
• v.40 no.3
• /
• pp.147-154
• /
• 2015

The scatter photons and photoneutrons from high energy photon beams (more than 10 MV) will increase the undesired dose to the patient and the staff working in linear accelerator room. This undesired dose which is found at out-of-field area can increase the probability of secondary malignancy. The purpose of this study is to determine the equivalent dose of scatter photons and neutrons generated by 3 different treatment techniques: 3D-conformal, intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). The measurement was performed using two types of the optically stimulation luminescence detectors (OSL and OSLN) in the Alderson Rando phantom that was irradiated by 3 different treatment techniques following the actual prostate cancer treatment plans. The scatter photon and neutron equivalent dose were compared among the 3 treatments techniques at the surface in the out-of-field area and the critical organs. Maximum equivalent dose of scatter photons and neutrons was found when using the IMRT technique. The scatter neutrons showed average equivalent doses of 0.26, 0.63 and $0.31mSv{\cdot}Gy^{-1}$ at abdominal surface region which was 20 cm from isocenter for 3D, IMRT and VMAT, respectively. The scattered photons equivalent doses were 6.94, 10.17 and $6.56mSv{\cdot}Gy^{-1}$ for 3D, IMRT and VMAT, respectively. For the 5 organ dose measurements, the scattered neutron and photon equivalent doses in out of field from the IMRT plan were highest. The result revealed that the scatter equivalent doses for neutron and photon were higher for IMRT. So the suitable treatment techniques should be selected to benefit the patient and the treatment room staff.

• Radiation Oncology Journal
• /
• v.13 no.3
• /
• pp.225-231
• /
• 1995

Malignant fibrous histiocytoma(MFH) of the maxilla is a rare malignant bone tumor Seven percents of all MFH occur in the head and neck. Approximately $12{\%}$ of these tumors occur in the maxilla. Local recurrence or distant metastasis was reported in $55{\%}$ of cases of maxillary MFH. The mean survival time of 30 months was reported from a review of 14 MFHs in the maxilla, mandible and oral soft tissues. MFH of the maxilla is best treated surgically but radical neck dissection does not appear to be indicated unless there is clinical evidence of lymph node metastases Although the use of radiation therapy for head and neck MFH has not been studied for a series of cases, individual cases of regression or histological change have been reported. Other authors have reported numbers of cases who received radiation therapy without benefit. Response to combination chemotherapy has been reported in $33{\%}$ of 23 patients with recurrent or metastatic MFH. We report here a case of MFH occurring in the maxilla with a review of literature about the clinical behavior and treatment of these lesions.

• Radiation Oncology Journal
• /
• v.37 no.2
• /
• pp.101-109
• /
• 2019

Purpose: The purpose of this study is to evaluate the safety and efficacy of the multimodality treatment with neoadjuvant intensity-modulated radiotherapy (IMRT) for resectable clinical T1-3N0-1M0 malignant pleural mesothelioma (MPM). Materials and Methods: A total of eleven patients who received neoadjuvant chemotherapy and radiotherapy between March 2016 and June 2018 were reviewed. Patients received 25 Gy in 5 fractions to entire ipsilateral hemithorax with helical tomotherapy. Results: All of patients were men with a median age of 56 years. Epithelioid subtype was found in 10 patients. All patients received neoadjuvant chemotherapy with pemetrexed-cisplatin regimen. Ten patients (90.9%) completed 25 Gy/5 fractions and one (9.0%) completed 20 Gy/4 fractions of radiotherapy. IMRT was well tolerated with only one acute grade 3 radiation pneumonitis. Surgery was performed 1 week (median, 8 days; range, 1 to 15 days) after completing IMRT. Extrapleural pneumonectomy was performed in 4 patients (36.3%), extended pleurectomy/decortication in 2 (18.2%) and pleurectomy/decortications in 5 (63.6%). There was no grade 3+ surgical complication except two deaths after EPP in 1 month. Based on operative findings and pathologic staging, adjuvant chemotherapy was delivered in 7 patients (63.6%), and 2 (18.2%) were decided to add adjuvant radiotherapy. After a median follow-up of 14.6 months (range, 2.8 to 30 months), there were 3 local recurrence (33.3%) and 1 distant metastasis (11.1%). Conclusion: Neoadjuvant entire pleural IMRT can be delivered with a favorable radiation complication. An optimal strategy has to be made in resectable MPM patients who would benefit from neoadjuvant radiation and surgery. Further studies are needed to look at long-term outcomes.