• Radiation Oncology Journal
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• v.33 no.4
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• pp.265-275
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• 2015

Despite the increasing use of stereotactic body radiation therapy (SBRT) and stereotactic radiation surgery (SRS) in recent years, the biological base of these high-dose hypo-fractionated radiotherapy modalities has been elusive. Given that most human tumors contain radioresistant hypoxic tumor cells, the radiobiological principles for the conventional multiple-fractionated radiotherapy cannot account for the high efficacy of SBRT and SRS. Recent emerging evidence strongly indicates that SBRT and SRS not only directly kill tumor cells, but also destroy the tumor vascular beds, thereby deteriorating intratumor microenvironment leading to indirect tumor cell death. Furthermore, indications are that the massive release of tumor antigens from the tumor cells directly and indirectly killed by SBRT and SRS stimulate anti-tumor immunity, thereby suppressing recurrence and metastatic tumor growth. The reoxygenation, repair, repopulation, and redistribution, which are important components in the response of tumors to conventional fractionated radiotherapy, play relatively little role in SBRT and SRS. The linear-quadratic model, which accounts for only direct cell death has been suggested to overestimate the cell death by high dose per fraction irradiation. However, the model may in some clinical cases incidentally do not overestimate total cell death because high-dose irradiation causes additional cell death through indirect mechanisms. For the improvement of the efficacy of SBRT and SRS, further investigation is warranted to gain detailed insights into the mechanisms underlying the SBRT and SRS.

• Journal of the Korean Society of Radiology
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• v.11 no.6
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• pp.437-442
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• 2017

Heavy ion therapy has a high cure rate for cancer cell. So many countries are introducing heavy ion therapy facility. When treating a cancer using heavy ion therapy, neutrons and gamma rays are generated and affect electronic equipment. A budget of about KRW 200 billion is needed to build a heavy ion therapy facility, and it takes more than five years to build it. Therefore it is important to observe the dose distribution in the treatment room using the monte carlo simulation before construction. In this study, we used the FLUKA of monte carlo simulation to investigate the dose distribution in the heavy ion treatment room.

• The Journal of Korean Society for Radiation Therapy
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• v.2 no.1
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• pp.31-40
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• 1987

In the case of designing a high dose rate remote controlled afterloading treatment room with existing hospital facilities. We must construct the effective protective barriers so as to reduce the primary and scattered radiation up to the maximum permissible dose level. It is difficult to reinforce the barrier thickness of the shielding requirements because of the limited space and the problem of the existing building structure at the surrounding area. Therefore we can reduce the intensity of primary radiation to the required degree at the location of interest with installing the appropriate I shaped Pb barriers between the radiation source and the shielding wall of the concrete. As a result, it was possible to reduce the intensity of the primary radiation below the M.P.D level by using additional Pb barriers instead of increasing thickness of concrete wall.

• Tuberculosis and Respiratory Diseases
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• v.78 no.3
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• pp.161-167
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• 2015

Tuberculosis (TB) remains a major global health problem, and the incidence of TB cases has not significantly decreased over the past decade in Korea. The standard short course regimen is highly effective against TB, but requires multiple TB-specific drugs and a long treatment duration. Recent studies using late-generation fluoroquinolones and/or high-dose rifapentine-containing regimens to shorten the duration of TB treatment showed negative results. Extending the treatment duration may be considered in patients with cavitation on the initial chest radiograph and positivity in sputum culture at 2 months of treatment for preventing TB relapse. Current evidence does not support the use of fixed-dose combinations compared to separate drugs for the purpose of improving treatment outcomes. All patients receiving TB treatment should be monitored regularly for response to therapy, facilitation of treatment completion, and management of adverse drug reactions. Mild adverse effects can be managed with symptomatic therapy and changing the timing of the drug administration, but severe adverse effects require a discontinuation of the offending drugs.

• Annals of Clinical Neurophysiology
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• v.22 no.1
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• pp.41-45
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• 2020

Acute sarcoid myositis is rarely complicated by sarcoidosis, and steroid therapy is considered the standard treatment. We experienced a patient with acute sarcoid myositis who did not respond to aggressive high-dose corticosteroid therapy, but showed a dramatic improvement after the addition of weekly low-dose oral methotrexate (MTX). This intervention allowed the resumption of normal daily activities after 6 months. Our case strongly suggests that MTX should be considered in patients with acute sarcoid myositis that is resistant to corticosteroid therapy.

• Journal of Medicine and Life Science
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• v.18 no.1
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• pp.1-10
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• 2021

Omega-3 fatty acids (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) may be beneficial for the primary and secondary prevention of cardiovascular events (CVEs), especially in patients with myocardial infarction or heart failure with reduced ejection fraction. For this purpose, one to two seafood meals per week is preferentially recommended. Omega-3 fatty acids with a high-dose EPA formula (4 g/day) may be more effective than EPA+DHA mixed supplements for the secondary prevention of CVE. Krill oil also contains omega-3 fatty acids, but at a much lower dose compared to fish oil. Supplemental vitamins and minerals have not shown the preventive effects on CVE in prospective, and randomized clinical trials, except for one Chinese study showing the stroke prevention effects of folic acid. The clinical benefit of chelation therapy in reducing CVEs is uncertain.

• Tuberculosis and Respiratory Diseases
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• v.47 no.1
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• pp.77-89
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• 1999

Background: High-dose chemotherapy is increasingly employed in many refractory malignant diseases. This therapy has been reported to increase response rate and survival benefits but it is also associated with higher treatment-related morbidity and mortality. We evaluated clinical characteristics and course of the pulmonary toxicity following high-dose chemotherapy with peripheral blood stem cell transplantation. Methods: Ninety-seven patients who had received high-dose chemotherapy with peripheral blood stem cell transplantation were evaluated. Five patients who developed lung lesions which were not related to infection nor primary malignant disease underwent transbronchial lung biopsy. The patients' clinical characteristics, treatments, and prognosis were reviewed retrospectively. Results: Five patients(5.1%) developed idiopathic pneumonia syndrome. The high dose chemotherapy regimens employed were cyclophosphamide, BCNU, and cisplatin in 3 cases, one case of BCNU, etoposide, Ara-C, and cyclophosphamide combination, and a regimen consisting of BCNU, etoposide, Ara-C, and melphalan. The total dose of BCNU used was 300-400 mg/$m^2$ and that of cyclophosphsmide was 6,000 mg/$m^2$. All of 5 patients received radiation therapy before this treatment. After an average duration of 14 weeks (4-26 weeks) of high-dose chemotherapy, patients developed cough, dyspnea and fever. The chest X-rays showed bilateral diffuse infiltration in 3 cases and the focal infiltration in the other 2 cases. All the patients received corticosteroid therapy as a treatment for the lung lesions. Two of them progressed to acute respiratory distress syndrome and died. Three patients recovered without residual lung lesion but one of them died of dilated cardiomyopathy. Conclusion: High-dose chemotherapy with peripheral blood stem cell transplantation especially which containing BCNU regimen may develop idiopathic pneumonia syndrome related to pulmonary toxicity and corticosteroid therapy may be bel1eficial in some cases.

• Biomedical Science Letters
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• v.23 no.2
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• pp.49-56
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• 2017

Fibroblast growth factor (FGF)-2 is one of the most effective growth factors to increase the growth rate of mesenchymal stem cells (MSCs). Previously, we reported that low dose of FGF-2 (1 ng/ml) induced proliferation of bone marrow-derived mesenchymal stem cells (BMSCs) through AKT and ERK activation resulting in reduction of autophagy and senescence, but not at a high dose. In this study, we investigated the effects of high dose FGF-2 (10 ng/ml) on proliferation, autophagy and senescence of BMSCs for long term cultures (i.e., 2 months). FGF-2 increased the growth rate of BMSCs in a dose dependent manner for a short term (3 days), while during long term cultures (2 months), population doubling time was increased and accumulated cell number was lower than control in BMSCs when cultured with 10 ng/ml of FGF-2. 10 ng/ml of FGF-2 induced immediate de-phosphorylation of ERK1/2, expression of LC3-II, and increase of senescence associated ${\beta}$-galactosidase (SA-${\beta}$-Gal, senescence marker) expression. In conclusion, we showed that 10 ng/ml of FGF-2 was inadequate for ex vivo expansion of BMSCs because 10 ng/ml of FGF-2 induced growth retardation via ERK1/2 de-phosphorylation and induction of autophagy and senescence in BMSCs.

• The Journal of Korean Society for Radiation Therapy
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• v.34
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• pp.7-12
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• 2022

Purpose: When it is difficult to secure the skin dose when treating Irregularly Shaped Skin Surface such as the nose where it is difficult to apply a bolus, increase the skin dose with a treatment plan that combines the IMRT (Intensity Modulated Radiation Therapy) delivery technique and FFF (Flattening Filter Free), It was tried to find out whether or not through the phantom experiment. Materials & Methods: Based on the 6MV-FF (Flattening Filter) and VMAT (Volumetric-Modulated Arc Therapy) treatment plans, which are the most commonly used treatment plans for head and neck cancer, A comparison group was created by combining VMAT and IMRT, FF and FFF, and the presence or absence of 5 mm bolus application. A virtual target was created on the Rando Phantom's nose, and a virtual bolus of 5 mm was applied assuming full contact on the Rando Phantom's nose. Five measurement points were determined based on the phantom's nose, and the absorbed dose was measured by irradiating each treatment plan 3 times per treatment plan according to the treatment technique and whether or not the bolus was applied. Result: The difference in skin dose in FF vs FFF increased in the case of FFF in VMAT bolus off, and there was no difference in case of IMRT bolus off. In VMAT bolus 5 mm and IMRT bolus 5 mm, it was confirmed that the skin dose was rather decreased in FFF. The difference in skin dose between VMAT and IMRT increased only in the case of FFF bolus off, and there was no statistical difference in the rest. For the difference in skin dose between bolus off vs bolus 5 mm, it was confirmed that the skin dose increased at bolus 5 mm, except for the case of using IMRT FFF. The treatment plan combining IMRT and FFF did not find any statistically significant difference as a result of analyzing the measured values of the treatment plan skin dose applied with a 5 mm bolus using the commonly used VMAT and FF. Therefore, it is thought that by using IMRT_FFF, it is possible to deliver a skin dose similar to that of applying a 5 mm bolus to VMAT_FF, which can be useful for patients who need a high skin dose but have difficulty applying a bolus. Conclusion: For patients who find it difficult to apply bolus, an increase in skin dose can be expected with a treatment plan that properly combines IMRT and FFF compared to VMAT and FF.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2453-2459
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• 2013

Bevacizumab has been approved for use in combination with chemotherapy to treat many types of cancer but associated neutropenic events, including febrile neutropenia, have been reported. To estimate the incidence and relative risk of neutropenic events in cancer patients treated with bevacizumab combination therapy, we searched PubMed, EMBASE, and Web of Science literature databases, as well as abstracts presented at the American Society of Clinical Oncology conferences, to identify relevant studies published from January 1966 to December 2011. Studies that compared bevacizumab plus chemotherapy or biological therapy with chemotherapy or biological therapy alone, and that had adequate safety data profiles, were selected for analysis. Statistical analyses were conducted to calculate the summary incidence rates, relative risks (RRs), and 95% confidence intervals (CIs) using fixed- or random-effects models. A total of 22 clinical trials involving 15,056 patients were included in the analysis. The summary incidences of high-grade neutropenia (HGN) and high-grade febrile neutropenia (HGFN) in patients receiving bevacizumab was 27.3% (95% CI: 26.4%-28.3%) and 3.91% (95% CI: 3.51%-4.37%), respectively. The risks of HGN (RR=1.10; 95% CI: 1.02-1.19; P=0.02) and HGFN (RR=1.31; 95% CI: 1.08-1.59; P=0.005) were significantly increased in bevacizumab-treated patients, compared to those who did not receive bevacizumab. The RR of bevacizumab-associated HGN, but not HGFN, varied significantly with tumor types (P=0.005). The increased risk of bevacizumab-associated neutropenic events was dose-dependent, as the RR was greater at a dose of 5 mg/kg/week than at 2.5 mg/kg/week. Our findings suggest that bevacizumab addition to cancer therapy significantly increases the risk of serious neutropenic events, and this risk may be dose-dependent.