• Journal of Korean Neurosurgical Society
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• v.57 no.5
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• pp.315-322
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• 2015

Intracranial germ cell tumors (ICGCT) occur in 2-11% of children with brain tumors between 0-19 years of age. For treatment of germinoma, relatively low radiation doses with or without chemotherapy show excellent 10 year survival rate of 80-100%. Past studies showed that neoadjuvant chemotherapy combined with focal radiotherapy resulted in unacceptably high rates of periventricular tumor recurrence. The use of generous radiation volume which covers the whole ventricular space with later boost treatment to primary site is considered as standard treatment of intracranial germinomas. For non-germinomatous germ cell tumors (NGGCT), 10-year overall survival rate is still much inferior than that of intracranial germinoma despite intensive chemotherapy and high-dose radiotherapy. Craniospinal radiotherapy combined with cisplatin-based chemotherapy provides the best treatment outcome for NGGCT; 60-70% of overall survival rate. There is a debate on the surgical role whether surgery can contribute to improved treatment outcome of NGGCT when added to combined chemoradiotherapy. Because higher dose of radiotherapy is required for treatment of NGGCT than for germinoma, it is tested whether whole ventricular irradiation can replace craniospinal irradiation in intermediate risk group of NGGCT to minimize radiation-related late toxicity in the recent studies. To minimize the treatment-related neural deficit and late sequelae while maintaining long-term survival rate of ICGCT patients, optimized administration of chemotherapy and radiotherapy should be selected. Use of technically upgraded radiotherapy modalities such as intensity-modulated radiotherapy or proton beam therapy is expected to bring an improved neurocognitive outcome with longitudinal assessment of the patients.

• Radiation Oncology Journal
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• v.35 no.3
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• pp.241-248
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• 2017

Purpose: To evaluate the efficacy and safety of extended-field radiation therapy for patients with thoracic superficial esophageal cancer (SEC). Materials and Methods: From May 2007 to October 2016, a total of 24 patients with thoracic SEC (T1a and T1b) who underwent definitive radiotherapy and were analyzed retrospectively. The median total radiotherapy dose was 64 Gy (range, 54 to 66 Gy) in conventional fractionation. All 24 patients received radiotherapy to whole thoracic esophagus and 23 patients received elective nodal irradiation. The supraclavicular lymph nodes, the celiac lymph nodes, and both of those nodal areas were included in 11, 3, and 9 patients, respectively. Results: The median follow-up duration was 28.7 months (range 7.9 to 108.0 months). The 3-year overall survival, local control, and progression-free survival rates were 95.2%, 89.7%, and 78.7%, respectively. There were 5 patients (20.8%) with progression of disease, 2 local failures (8.3%) and 3 (12.5%) regional failures. Three patients also experienced distant metastasis and had died of disease progression. There were no treatment-related toxicities of grade 3 or higher. Conclusion: Definitive extended-field radiotherapy for thoracic SEC showed durable disease control rates in medically inoperable and endoscopically unfit patients. Even extended-field radiotherapy with elective nodal irradiation was safe without grade 3 or 4 toxicities.

• Journal of Chest Surgery
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• v.53 no.4
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• pp.184-190
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• 2020

Radiation therapy (RT) has improved patient outcomes, but treatment-related complication rates remain high. In the conventional 2-dimensional and 3-dimensional conformal RT (3D-CRT) era, there was little room for toxicity reduction because of the need to balance the estimated toxicity to organs at risk (OARs), derived from dose-volume histogram data for organs including the lung, heart, spinal cord, and liver, with the planning target volume (PTV) dose. Intensity-modulated RT (IMRT) is an advanced form of conformal RT that utilizes computer-controlled linear accelerators to deliver precise radiation doses to the PTV. The dosimetric advantages of IMRT enable better sparing of normal tissues and OARs than is possible with 3D-CRT. A major breakthrough in the treatment of esophageal cancer (EC), whether early or locally advanced, is the use of proton beam therapy (PBT). Protons deposit their highest dose of radiation at the tumor, while leaving none behind; the resulting effective dose reduction to healthy tissues and OARs considerably reduces acute and delayed RT-related toxicity. In recent studies, PBT has been found to alleviate severe lymphopenia resulting from combined chemo-radiation, opening up the possibility of reducing immune suppression, which might be associated with a poor prognosis in cases of locally advanced EC.

• 대한방사선방어학회:학술대회논문집
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• 2011.11a
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• pp.204-205
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• 2011

• Radiation Oncology Journal
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• v.32 no.4
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• pp.238-246
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• 2014

Purpose: To evaluate the clinical outcome of high-dose-rate (HDR) interstitial brachytherapy (IBT) in patients with oral cavity cancer. Materials and Methods: Sixteen patients with oral cavity cancer treated with HDR remote-control afterloading brachytherapy using $^{192}Ir$ between 2001 and 2013 were analyzed retrospectively. Brachytherapy was administered in 11 patients as the primary treatment and in five patients as salvage treatment for recurrence after the initial surgery. In 12 patients, external beam radiotherapy (50-55 Gy/25 fractions) was combined with IBT of 21 Gy/7 fractions. In addition, IBT was administered as the sole treatment in three patients with a total dose of 50 Gy/10 fractions and as postoperative adjuvant treatment in one patient with a total of 35 Gy/7 fractions. Results: The 5-year overall survival of the entire group was 70%. The actuarial local control rate after 3 years was 84%. All five recurrent cases after initial surgery were successfully salvaged using IBT ${\pm}$ external beam radiotherapy. Two patients developed local recurrence at 3 and 5 months, respectively, after IBT. The acute complications were acceptable (${\leq}grade$ 2). Three patients developed major late complications, such as radio-osteonecrosis, in which one patient was treated by conservative therapy and two required surgical intervention. Conclusion: HDR IBT for oral cavity cancer was effective and acceptable in diverse clinical settings, such as in the cases of primary or salvage treatment.

• Progress in Medical Physics
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• v.30 no.4
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• pp.112-119
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• 2019

Purpose: The advantages of ocular proton therapy are that it spares the optic nerve and delivers the minimal dose to normal surrounding tissues. In this study, it developed a solid eye phantom that enabled us to perform quality assurance (QA) to verify the dose and beam range for passive single scattering proton therapy using a single phantom. For this purpose, a new solid eye phantom with a polymethyl-methacrylate (PMMA) wedge was developed using film dosimetry and an ionization chamber. Methods: The typical beam shape used for eye treatment is approximately 3 cm in diameter and the beam range is below 5 cm. Since proton therapy has a problem with beam range uncertainty due to differences in the stopping power of normal tissue, bone, air, etc, the beam range should be confirmed before treatment. A film can be placed on the slope of the phantom to evaluate the Spread-out Bragg Peak based on the water equivalent thickness value of PMMA on the film. In addition, an ionization chamber (Pin-point, PTW 31014) can be inserted into a hole in the phantom to measure the absolute dose. Results: The eye phantom was used for independent patient-specific QA. The differences in the output and beam range between the measurement and the planned treatment were less than 1.5% and 0.1 cm, respectively. Conclusions: An eye phantom was developed and the performance was successfully validated. The phantom can be employed to verify the output and beam range for ocular proton therapy.

• 대한두경부종양학회:학술대회논문집
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• 2005.11a
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• pp.239-240
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• 2005

• 대한두경부종양학회:학술대회논문집
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• 2004.11a
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• pp.232-232
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• 2004

• Radiation Oncology Journal
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• v.35 no.3
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• pp.189-197
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• 2017

Locally advanced prostate cancer (LAPC) is defined as histologically proven T3-4 prostatic adenocarcinoma. In this review, we define the individual roles of radiotherapy (RT), short-term (ST-) and long-term (LT-) androgen deprivation therapy (ADT), and their combination in multimodal therapy for LAPC. Despite limitations in comparing the clinical outcomes among published papers, in the present study, a trend of 10-year clinical outcomes was roughly estimated by calculating the average rates weighted by the cohort number. With RT alone, the following rates were estimated: 87% biochemical failure, 34% local failure (LF), 48% distant metastasis (DM), 38% overall survival (OS), and 27% disease-specific mortality (DSM). Those associated with ADT alone were 74% BCF, 54% OS, and 25% DSM, which appeared to be better than those of RT alone. The addition of ADT to RT produced a notable local and systemic effect, regardless of ST- or LT-ADT. The LF rate decreased from 34% with RT alone to 21% with ST-ADT and further to 15% with LT-ADT. The DM and DSM rates also showed a similar trend among RT alone, RT+ST-ADT, and RT+LT-ADT. The combination of RT+LT-ADT resulted in the best long-term clinical outcomes, indicating that both RT and ADT are important parts of multimodal therapy.

• Nutrition Research and Practice
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• v.12 no.1
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• pp.41-46
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• 2018

BACKGROUND/OBJECTIVES: Exposure of the normal lung tissue around the cancerous tumor during radiotherapy causes serious side effects such as pneumonitis and pulmonary fibrosis. Radioprotectors used during cancer radiotherapy could protect the patient from side effects induced by radiation injury of the normal tissue. Delphinidin has strong antioxidant properties, and it works as the driving force of a radioprotective effect by scavenging radiation-induced reactive oxygen species (ROS). However, no studies have been conducted on the radioprotective effect of delphinidin against high linear energy transfer radiation. Therefore, this study was undertaken to evaluate the radioprotective effects of delphinidin on human lung cells against a proton beam. MATERIALS/METHODS: Normal human lung cells (HEL 299 cells) were used for in vitro experiments. The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay assessed the cytotoxicity of delphinidin and cell viability. The expression of radiation induced cellular ROS was measured by the 2'-7'-dicholordihydrofluorescein diacetate assay. Superoxide dismutase activity assay and catalase activity assay were used for evaluating the activity of corresponding enzymes. In addition, radioprotective effects on DNA damage-induced cellular apoptosis were evaluated by Western blot assay. RESULTS: Experimental analysis, including cell survival assay, MTT assay, and Western blot assay, revealed the radioprotective effects of delphinidin. These include restoring the activities of antioxidant enzymes of damaged cells, increase in the levels of pro-survival protein, and decrease of pro-apoptosis proteins. The results from different experiments were compatible with each to provide a substantial conclusion. CONCLUSION: Low concentration ($2.5{\mu}M/mL$) of delphinidin administration prior to radiation exposure was radioprotective against a low dose of proton beam exposure. Hence, delphinidin is a promising shielding agent against radiation, protecting the normal tissues around a cancerous tumor, which are unintentionally exposed to low doses of radiation during proton therapy.