• Progress in Medical Physics
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• v.15 no.2
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• pp.77-83
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• 2004

The commissioning of a model-based treatment planning system requires many parameters to fit the measured depth doses and transverse profiles. For the commissioning of the Pinnacle$^3$ system, through the Monte Carlo (MC) simulation, the necessary parameters, including the photon spectrum, contaminant electrons, off-axis softening and fluency of photons, were observed. Through the simulation the parameters contained valuable information, but the calculated results of the Pinnacle$^3$ using the MC-derived parameters showed discrepancies with those measured for the off-axis softening and the fluency of photons. Even though the MC calculation produces reasonable values for the commissioning, the thorough physical basis of the Pinnacle$^3$'s commissioning process is needed in order to directly use the MC derived parameters.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.204-208
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• 2009

The withdrawal time of erythromycin in cultured olive flounder was investigated to ensure the food safety of the fish treated with erythromycin. The oral administration of erythromycin was carried out using the experimental diet containing erythromycin (200 mg/kg) daily dose of 40 mg/kg body weight. The 45 day experimental period was broken into 7 days of habituation, 8 days of medication and 30 days of additional feeding without antibiotics. The erythromycin concentration in the flounder muscle had been increased gradually with medication. After 5 days of medication, the concentration increased to its maximum level of 6.05 mg/kg. After discontinuing the antibiotic, the erythromycin concentration decreased drastically and day 9 was below 0.1 mg/kg. The erythromycin concentration had slowly declined from the 6th to the 20th day after medication and disappeared completely after 25 days. From these results, the time needed to reduce the erythromycin level to the 0.2 mg/kg limit adopted by the ED and Japan was suspected to be 4-6 days. Therefore, a reasonable withdrawal time following ED and Japanese regulatory guidelines for erythromycin in the cultured flounder could be estimated to be 10 days.

• Journal of Korean Neurosurgical Society
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• v.29 no.10
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• pp.1345-1351
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• 2000

Objective : Around the sellar area, there are many important structures. But, the optimal radiation dosage for minimal toxicity to surrounding neural tissue has not been firmly established. The purpose of this study is to evaluate the radiosurgical outcome of juxtasellar tumors and to investigate the relationship between radiation dosage and toxicity to neural tissue. Method : Between May 1992 and June 2000, we treated 65 juxtasellar tumors by using the Leksell Gamma Knife. Among them, 52 patients who could be followed more than 1 year were included in this study. The radiosurgical dosage to the optic pathway, cavernous sinus, Meckel's cave, hypothalamus, pituitary gland and stalk, and brain stem was analyzed and correlated with clinical outcome. The mean follow-up period was 33.5 months(range 12.2- 99.0 months). Result : The clinical response rate was 69.2%. The volume response rate was 61.0% and the radiologic control rate was 92.7%. There were 4 complications(7.7%) of 2 trigeminal neuropathy, 1 abducens nerve palsy, and 1 trigeminal and transient abducens nerve palsy. The optic apparatus appeared to tolerate doses greater than 10Gy. The risk of cranial nerve complications in cavernous sinus seemed to be related to doses of more than 16Gy. In 3 of 4 patients who received more than 16Gy to cavernous sinus, the abducens or trigeminal neuropathy occurred. Also, one patient who received more than 15Gy to the Meckel's cave, trigeminal neuropathy developed. The hypothalamus, pituitary gland and stalk, and brain stem were relatively tolerable to radiation. Conclusion : Gamma Knife radiosurgery seems to be an effective method to control the growth of juxtasellar tumors. To avoid injury to surrounding important neural tissue, careful dose planning and further study for radiation toxicity to neural tissue were needed.

• Radiation Oncology Journal
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• v.35 no.2
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• pp.163-171
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• 2017

Purpose: Although stereotactic ablative body radiotherapy (SABR) is widely used therapeutic technique, predictive factors of radiation pneumonitis (RP) after SABR remain undefined. We aimed to investigate the predictive factors affecting RP in patients with primary or metastatic lung tumors who received SABR. Materials and Methods: From 2012 to 2015, we reviewed 59 patients with 72 primary or metastatic lung tumors treated with SABR, and performed analyses of clinical and dosimetric variables related to symptomatic RP. SABR was delivered as 45-60 Gy in 3-4 fractions, which were over 100 Gy in BED when the ${\alpha}/{\beta}$ value was assumed to be 10. Tumor volume and other various dose volume factors were analyzed using median value as a cutoff value. RP was graded per the Common Terminology Criteria for Adverse Events v4.03. Results: At the median follow-up period of 11 months, symptomatic RP was observed in 13 lesions (12 patients, 18.1%), including grade 2 RP in 11 lesions and grade 3 in 2 lesions. Patients with planning target volume (PTV) of ${\leq}14.35mL$ had significantly lower rates of symptomatic RP when compared to others (8.6% vs. 27%; p = 0.048). Rates of symptomatic RP in patients with internal gross tumor volume (iGTV) >4.21 mL were higher than with ${\leq}4.21mL$ (29.7% vs. 6.1%; p = 0.017). Conclusions: The incidence of symptomatic RP following treatment with SABR was acceptable with grade 2 RP being observed in most patients. iGTV over 4.21 mL and PTV of over 14.35 mL were significant predictive factors related to symptomatic RP.

• Radiation Oncology Journal
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• v.35 no.2
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• pp.172-179
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• 2017

Purpose: To evaluate the outcomes of stereotactic body radiation therapy (SBRT) for patients with liver oligo-recurrence and oligo-progression from various primary tumors. Materials and Methods: Between 2002 and 2013, 72 patients with liver oligo-recurrence (oligo-metastasis with a controlled primary tumor) and oligo-progression (contradictory progression of a few sites of disease despite an overall tumor burden response to therapy) underwent SBRT. Of these, 9 and 8 patients with uncontrollable distant metastases and patients immediate loss to follow-up, respectively, were excluded. The total planning target volume was used to select the SBRT dose (median, 48 Gy; range, 30 to 60 Gy, 3-4 fractions). Toxicity was evaluated using the Common Toxicity Criteria for Adverse Events v4.0. Results: We evaluated 55 patients (77 lesions) treated with SBRT for liver metastases. All patients had controlled primary lesions, and 28 patients had stable lesions at another site (oligo-progression). The most common primary site was the colon (36 patients), followed by the stomach (6 patients) and other sites (13 patients). The 2-year local control and progression-free survival rates were 68% and 22%, respectively. The 2- and 5-year overall survival rates were 56% and 20%, respectively. The most common adverse events were grade 1-2 fatigue, nausea, and vomiting; no grade ${\geq}3$ toxicities were observed. Univariate analysis revealed that oligo-progression associated with poor survival. Conclusion: SBRT for liver oligo-recurrence and oligo-progression appears safe, with similar local control rates. For liver oligo-progression, criteria are needed to select patients in whom improved overall survival can be expected through SBRT.

• Journal of Preventive Medicine and Public Health
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• v.51 no.5
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• pp.227-233
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• 2018

Objectives: Chronic diseases, including back pain, result in significant patient morbidity and societal burden. Overall improvement in physical fitness is recommended for prevention and treatment. Walking is a convenient modality for achieving initial gains. Our objective was to determine whether neighbourhood walkability, acting as a surrogate measure of physical fitness, was associated with the presence of chronic disease. Methods: We conducted a cross-sectional study of prospectively collected data from a prior randomized cohort study of 227 patients referred for tertiary assessment of chronic back pain in Ottawa, ON, Canada. The Charlson Comorbidity Index (CCI) was calculated from patient-completed questionnaires and medical record review. Using patients' postal codes, neighbourhood walkability was determined using the Walk Score, which awards points based on the distance to the closest amenities, yielding a score from 0 to 100 (0-50: car-dependent; 50-100: walkable). Results: Based on the Walk Score, 134 patients lived in car-dependent neighborhoods and 93 lived in walkable neighborhoods. A multivariate logistic regression model, adjusted for age, gender, rural postal code, body mass index, smoking, median household income, percent employment, pain, and disability, demonstrated an adjusted odds ratio of 2.75 (95% confidence interval, 1.16 to 6.53) times higher prevalence for having a chronic disease for patients living in a car-dependent neighborhood. There was also a significant dose-related association (p=0.01; Mantel-Haenszel chi-square=6.4) between living in car-dependent neighbourhoods and more severe CCI scores. Conclusions: Our findings suggest that advocating for improved neighbourhood planning to permit greater walkability may help offset the burden of chronic disease.

• Radiation Oncology Journal
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• v.2 no.2
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• pp.287-297
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• 1984

The normal intracranial structures are relatively resistant to therapeutic radiation, but may react adversely in a variety of ways, and the damage to nerve tissue may be slow in making its appearance, and once damage has occured the patient recovers slowly and incompletly. Therefore, it is important to consider the possibility of either recurrent tumor or late adverse effect in any patient who has had radiotherapy. The determination o( rnorphological/pathological correlation is very important to the therapeutic radiologist who uses CT scans to define a treatment volume, as well as to the clinician who wishes to explain the patient's clinical state in terms of regress, progression, persistence, or recurrence of tumor or radiation-induced edema or necrosis, The authors are obtained as following results ; 1. The field size(whole CNS, large, intermediate, small field) was variable according to the location and extension of tumor and histopathologic diagnosis, and the tatal tumor dose was 4,000 to 6,000 rads except one of recurred case of 9,100 rads. The duration of follow up CT scan was from 3 months to 5 year 10 months. 2, The histopathologic diagnosis of 9cases were glioblastoma multiforme(3 cases), pineal tumor (3), oligodendroglioma (1), cystic astrocytoma (1), pituitary adenoma (1) and their adverse effects after radiation therapy were brain atrophy (4 cases) , radiation necrosis(2), tumor recurrence with or without calcification (2), radiation·induced infarction (1). 3. The recurrent symptoms after radiation therapy of brain tumor were not always the results of regrowth of neoplasm, but may represent late change of irradiated brain. 4. It must be need that we always consider the accurate treatment planning and proper treatment method to reduce undesirable late adverse effects in treatment of brain tumors.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3365-3370
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• 2015

Radiotherapy has an important role in the treatment of prostate cancer. Three-dimensional conformal radiation therapy (3D-CRT), intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) techniques are all applied for this purpose. However, the risk of secondary radiation-induced bladder cancer is significantly elevated in irradiated patients compared surgery-only or watchful waiting groups. There are also reports of risk of secondary cancer with low doses to normal tissues. This study was designed to compare received volumes of low doses among 3D-CRT, IMRT and VMAT techniques for prostate patients. Ten prostate cancer patients were selected retrospectively for this planning study. Treatment plans were generated using 3D-CRT, IMRT and VMAT techniques. Conformity index (CI), homogenity index (HI), receiving 5 Gy of the volume (V5%), receiving 2 Gy of the volume (V2%), receiving 1 Gy of the volume (V1%) and monitor units (MUs) were compared. This study confirms that VMAT has slightly better CI while thev olume of low doses was higher. VMAT had lower MUs than IMRT. 3D-CRT had the lowest MU, CI and HI. If target coverage and normal tissue sparing are comparable between different treatment techniques, the risk of second malignancy should be a important factor in the selection of treatment.

• Radiation Oncology Journal
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• v.5 no.2
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• pp.169-172
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• 1987

Currently, many computer systems are used in many areas of medicine including radiation oncology. For the most part, the computer system has proved to be useful in radiotherapeutic planning and dose calculation. There has been attempts to develop computer system including information management of patients, patient tracing, and office automation in radiation oncology department. But some of these available commercial systems have shortcomings. We developed a management system of patients in our radiation oncology department that integrated most of items for the evaluation of patents. In particular, the data were stored in a natural language (noncoded) and made themselves easily understandable by all clinical groups. In addition , the data could be isolated in files from which the computer could generate graphs and static data by the use of some simple commands. The system provided us with not only the functions of case review but functions of preparation of conferences, lectures and resident teaching.

• Radiation Oncology Journal
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• v.37 no.1
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• pp.43-50
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• 2019

Purpose: The aim of this retrospective study was to investigate the use of a radiopaque tissue fiducial marker (TFM) in the treatment of prostate cancer patients who undergo post-prostatectomy radiotherapy (PPRT). TFM safety, its role and benefit in quantifying the set-up uncertainties in patients undergoing PPRT image-guided radiotherapy were assessed. Materials and Methods: A total of 45 consecutive PPRT patients underwent transperineal implantation of TFM at the level of vesicourethral anastomosis in the retrovesical tissue prior to intensity-modulated radiotherapy. Prostate bed motion was calculated by measuring the position of the TFM relative to the pelvic bony anatomy on daily cone-beam computed tomography. The stability and visibility of the TFM were assessed in the initial 10 patients. Results: No postoperative complications were recorded. A total of 3,500 images were analysed. The calculated prostate bed motion for bony landmark matching relative to TFM were 2.25 mm in the left-right, 5.89 mm in the superior-inferior, and 6.59 mm in the anterior-posterior directions. A significant 36% reduction in the mean volume of rectum receiving 70 Gy (rV₇₀) was achieved for a uniform planning target volume (PTV) margin of 7 mm compared with the Australian and New Zealand Faculty of Radiation Oncology Genito-Urinary Group recommended PTV margin of 10 mm. Conclusion: The use of TFM was safe and can potentially eliminate set-up errors associated with bony landmark matching, thereby allowing for tighter PTV margins and a consequent favourable reduction in dose delivered to the bladder and rectum, with potential improvements in toxicities.