• 대한두경부종양학회:학술대회논문집
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• 2003.11a
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• pp.239-239
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• 2003

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.351-356
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• 2022

The purpose of this study was to evaluate the cancer incidence rate and provide basic data by measuring the photoneutron dose generated during intensity-modulated radiation therapy and volumetric modulated arc therapy used in radiation therapy for prostate cancer. The optically stimulated luminescence albedo neutron dosimeter for neutron measurement was placed on the Rando phantom in the abdomen and thyroid and photoneutron dose generated was measured. As a result of the study, intensity-modulated radiation therapy (7 portal) was measured to be higher than volumetric rotational radiation therapy in both abdominal and thyroid locations. When the cancer incidence rate was evaluated using the nominal risk coefficient of ICRP 103, the cancer incidence rate due to exposure to the colon and thyroid during intensity-modulated radiation therapy was 9.9 per 1,000 people, and volumetric rotational radiation therapy for 1,000 people. It was 3.5 per person. Based on the principle of ALARA (As low as reasonably archievable), it is considered to be a guideline for minimizing the exposure dose to normal organs in the establishment of a radiation treatment plan.

• Radiation Oncology Journal
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• v.29 no.3
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• pp.135-146
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• 2011

With the advance of modern radiation therapy technique, radiation dose conformation and dose distribution have improved dramatically. However, the progress does not completely fulfi ll the goal of cancer treatment such as improved local control or survival. The discordances with the clinical results are from the biophysical nature of photon, which is the main source of radiation therapy in current field, with the lower linear energy transfer to the target. As part of a natural progression, there recently has been a resurgence of interest in particle therapy, specifically using heavy charged particles, because these kinds of radiations serve theoretical advantages in both biological and physical aspects. The Korean government is to set up a heavy charged particle facility in Korea Institute of Radiological & Medical Sciences. This review introduces some of the elementary physics of the various particles for the sake of Korean radiation oncologists' interest.

• Journal of Veterinary Clinics
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• v.34 no.4
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• pp.299-303
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• 2017

An 11-year-old neutered male Maltese presented for radiation therapy for nasal transitional cell carcinoma. Stereotactic body radiation therapy (SBRT) was provided for the owner's request. Clinical signs improved 6 days after radiation therapy. Adverse effects including alopecia and pigmentation on the facial region were observed at 21 days after radiation therapy. The first follow-up computed tomography (CT) 96 days after SBRT revealed that the nasal tumor had decreased by 60.63% compared with the pre-treatment volume. Clinical signs related with the tumor reassigned 151 days after SBRT, and the second follow-up CT revealed tumor relapse. The patient was died 238 days after SBRT due to tumor relapse. SBRT showed a good tumor control effect with relatively mild radiation toxicity relative to other radiation therapy modalities, in accordance with a previous study. Further studies are needed to establish an effective treatment protocol, such as total dose, fractional dose, and inter-fractional period, in canine malignant nasal tumors.

• Radiation Oncology Journal
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• v.34 no.2
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• pp.128-134
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• 2016

Purpose: To evaluate the clinical outcomes of patients who underwent radiation therapy with or without targeted molecular therapy for the treatment of spinal metastasis from renal cell carcinoma (RCC). Materials and Methods: A total of 28 spinal metastatic lesions from RCC patients treated with radiotherapy between June 2009 and June 2015 were retrospectively reviewed. Thirteen lesions were treated concurrently with targeted molecular therapy (concurrent group) and 15 lesions were not (nonconcurrent group). Local control was defined as lack of radiographically evident local progression and neurological deterioration. Results: At a median follow-up of 11 months (range, 2 to 58 months), the 1-year local progression-free rate (LPFR) was 67.0%. The patients with concurrent targeted molecular therapy showed significantly higher LPFR than those without (p = 0.019). After multivariate analysis, use of concurrent targeted molecular therapy showed a tendency towards improved LPFR (hazard ratio, 0.13; 95% confidence interval, 0.01 to 1.16). There was no difference in the incidence of systemic progression between concurrent and nonconcurrent groups. No grade ${\geq}2$ toxicities were observed during or after radiotherapy. Conclusion: Our study suggests the possibility that concurrent use of targeted molecular therapy during radiotherapy may improve LPFR. Further study with a large population is required to confirm these results.

• Radiation Oncology Journal
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• v.11 no.2
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• pp.277-283
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• 1993

Background: We peformed a retroslective study in patients with previously untreated advanced (Stage III or IV) laryngeal and hypopharyngeal cancer to compare the results of induction chemotherapy followed by definitive radiation therapy (CT+ RT) with those of conventional laryngectomy and postoperative radiation therapy (OP + RT). Method: Between 1985 and 1990, twenty-four patients were treated with two or three courses of chemotherapy and radiation therapy (66-75 Gy). Twenty-five patients were received laryngectomy and radical neck dissection (except 3 patients) and postoperative radiation therapy (55~64 Gy). Result: After a median fellow-up of 20 months, the actusrial 5-year overall survival rate was $24\%$ (chemotherapy group) and $36\%,$ (op group). (P>0.1). The local control rate was the $65\%,$ (13/20) and $68.2\%,$ (15/22). (p>0.1). The rate of laryngeal preservation was $65\%$ (13/20) in chemotherapy group. Conclusion: Induction chemotherapy and definitive radiation therapy can be effective in preserving the larynx in a high percentage of patients with advanced laryngeal and hypopharyngeal cancer.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.61-64
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• 2002

As intensity modulated radiation therapy compared with conventional radiation therapy, tumor target dose increased and normal tissues and critical organs dose reduced. In brain tumor, treatment planning of intensity modulated radiation therapy was practiced in 4MV, 6MV, 15MV X-ray energy. In these X-ray energy, was considered the dose distribution and dose volume histogram. As 4MV X-ray compared with 6MV and 15MV, maximum dose of right optic-nerve increased 10.1 %, 8.4%. Right eye increased 5.2%, 2.7%. And left optic-nerve, left eye, optic chiasm and brainstem incrased 1.7% - 5.2%. Even though maximum dose of PTV and these critical organs show different from 1.7% - 10.1% according to X-ray energies, these are a piont dose. Therefore in brain tumor, treatment planning of intensity modulated radiation therapy in 9 treatment field showed no relation with energy dependency.

• Korean Journal of Head & Neck Oncology
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• v.14 no.1
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• pp.15-19
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• 1998

Objectives: It is expected that the combined cisplatin and radiation therapy for nasopharyngeal carcinoma produces more sensory neural hearing losses compared to radiation therapy alone. The purpose of this study was to evaluate the incidence of sensory neural hearing losses after concurrent cisplatin and radiation therapy for nasopharyngeal carcinoma. Materials and Methods: From Jun. 1994 to Mar. 1997, 10 patients were available for this study with the following eligibility criteria: 1) The patients received concurrent cisplatin and radiation therapy for nasopharyngeal carcinoma. 2) There was no pre-existing auditory disease except serous otitis media due to nasopharyngeal carcinoma. 3) They had normal sensorineural hearing function on the pretreatment pure tone audiogram. 4) Pure tone audiograms were performed at least one time after treatment between 6months to 1 year follow-up without local recurrence. Results: At 1 year follow-up, 3 patients complained of decreased hearing capacity. Sensorineural hearing losses were developed in 15 ears out of 20(75%) and were more frequent and severe in high frequency area on pure tone audiogram. Conclusion: The concurrent cisplatin and radiation therapy for nasopharyngeal carcinoma may produce sensorineural hearing losses more frequently compared to historical data of radiation therapy alone and close evaluations with regular audiograms are necessary even in patients without symptoms and signs of hearing impairment.

• Journal of the Korea Safety Management & Science
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• v.17 no.4
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• pp.199-206
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• 2015

The purpose of this study was to investigate radiation dose sensitivity due to displacement of human extremities in the water bolus box on radiation therapy. Water bolus box and human thigh with femur bone were constructed in computerized radiation therapy planning system to verify the absorbed dose. Two 6MV X-ray beams were irradiated bilaterally into water bolus box and then radiation dose were calculated each situation at displacement of middle axis of thigh from the center in water bolus box to right and left direction. Absorbed dose of thigh and femur bone increased by the distance of displacement. The maximum dose of thigh even increased 20% over than prescribed dose. This is in contrast to conventional concept of dose distribution in water bolus box. Based on this result, displacement of body site in the water bolus box have to be averted during radiation therapy.

• The Journal of Korean Society for Radiation Therapy
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• v.6 no.1
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• pp.84-88
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• 1994

Proper evaluation about the penumbra is very important to improve the efficacy of radiation theraphy. There are two kinds of physical penumbra, geometric penumbra and transmission penumbra. In this study, we evaluated the variation of physical penumbra according to the varing enery level, changing the field size and depth. Physical penumbra width was decreased as the source size decreased, and as the SDD increased, but the consideration about the scatter radiation and mechanical stability is an important factor. For the two adjacent beams, upper collimator should be used and especially for Co-60 unit, it is efficient to use the extended collimator.