• Progress in Medical Physics
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• v.11 no.1
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• pp.59-71
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• 2000

It is possible to obtain a fast CT scan during breath holding with spiral technique. But the risk of radiation is increased due to detailed and repeated scans. However, the limitation of X-ray doses is not fully specified on CT, yet. Therefore, the purpose of the present study is to define the limitation of X-ray doses on CT The CT unit was somatom plus 4. Alderson Rando phantom, Solenoid water phantom, TLD, and reader were used. For determining adequate position and size of organs, the measurement of distance(${\pm}$2mm) from the midline of vertebral body was performed in 40 women(20~40 years). On the brain scan for 8:8(8mm slice thickness, 8mm/sec movement velocity of the table) and 10:10(10mm slice thickness, 10mm/sec movement velocity of the table) methods, the absorption doses of exposed area of the 10:10 were slightly higher than those of 8:8. The doses of unexposed uterus were negligible on the brain scan for both 8:8 and 10:10. On the chest scan for 8:8, 8:10(8mm slice thickness, 10mm/sec movement velocity of the table), 10:10, 10:12(10mm slice thickness, 12mm/sec movement velocity of the table) and 10:15(10mm slice thickness, 15mm/sec movement velocity of the table) methods, 8:8 method of the absorption doses of exposure area was the most highest and 10:15 method was the most lowest. The absorption doses of 8:10 method was relatively lower than those of the other methods. In conclusion, the 8:10 method is the most suitable to give a low radiation burden to patient without distorting image quality.

• Radiation Oncology Journal
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• v.12 no.2
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• pp.233-241
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• 1994

Purpose : This study was performed to verify dose distribution with the tissue compensator which is used for uniform dose distribution in total body irradiation(TBI). Materials and methods : The compensators were made of lead(0.8mm thickness) and aluminum(1mm or 5mm thickness) plates. The humanoid phantom of adult size was made of paraffin as a real treatment position for bilateral total body technique. The humanoid phantom was set at 360cm of source-axis distance(SAD) and irradiated with geographical field size(FS) $144{\times}144cm^2(40{\times}40cm^2$ at SAD 100cm) which covered the entire phantom. Irradiation was done with 10MV X-ray(CLINAC 1800, Varian Co., USA) of linear accelerator set at Department of Therapeutic Radiology, Chonnam University Hospital. The midline absorbed dose was checked at the various regions such as head, mouth, mid-neck, sternal notch, mid-mediastinum, xiphoid, umbilicus, pelvis, knee and ankle with or without compensator, respectively. We used exposure/exposure rate meter(model 192, Capintec Inc., USA) with ionization chamber(PR 05) for dosimetry, For the dosimetry of thorax region TLD rods of $1x1x6mm^3$ in volume(LiF, Harshaw Co., Netherland) was used at the commercially available humanoid phantom. Results : The absorbed dose of each point without tissue compensator revealed significant difference(from $-11.8\%\;to\;21.1\%$) compared with the umbilicus dose which is a dose prescription point in TBI. The absorbed dose without compensator at sternal notch including shoulder was $11.8\%$ less than the dose of umbilicus. With lead compensator the absorbed doses ranged from $+1.3\%\;to\;-5.3\%$ except mid-neck which revealed over-compensation($-7.9\%$). In case of aluminum compensator the absorbed doses were measured with less difference(from $-2.6{\%}\;to\;5.3\%$) compared with umbilicus dose. Conclusion : Both of lead and aluminum compensators applied to the skull or lower leg revealed a good compensation effect. It was recognized that boost irradiation or choosing reference point of dose prescription at sternal notch according to the lateral thickness of patient in TBI should be considered.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.189-196
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• 2012

Purpose: The sufficiency of skin dose and the reemergence of patient set-up position to the success of skin cancer radiation treatment is a very important element. But the conventional methods to increase the skin dose were used to vacuum cushion, bolus and water tank have several weak points. For this reason, we producted Foxtail Millet Vacuum Cushion and evaluated the efficiency of the Foxtail Millet Vacuum Cushion in skin cancer Radiation treatment. Materials and Methods: We measured absolute dose for 3 materials (Foxtail Millet Vacuum Cushion, bolus and solid water phantom) and compared each dose distribution. We irradiated 6 MV 100 MU photon radiation to every material of 1 cm, 2 cm, 3 cm thickness at three times. We measured absolute dose and compared dose distribution. Finally we inspected the CT simulation and radiation therapy planing using the Foxtail Millet Vacuum Cushion. Results: Absolute dose of Foxtail Millet Vacuum Cushion was similar to absolute dose of bolus and solid water phantom's result in each thickness. it Showed only the difference of 0.1~0.2% between each material. Also the same result in dose distribution comparison. About 97% of the dose distribution was within the margin of error in the prescribed ranges ($100{\pm}3%$), and achieved the enough skin dose (Gross Tumor Volume dose : $100{\pm}5%$) in radiation therapy planing. Conclusion: We evaluated important fact that Foxtail Millet Vacuum Cushion is no shortage of time to replace the soft tissue equivalent material and normal vacuum cushion at the low energy radiation transmittance. Foxtail Millet Vacuum Cushion can simultaneously achieve the enough skin dose in radiation therapy planing with maintaining normal vacuum cushion' function. Therefore as above We think that Foxtail Millet Vacuum Cushion is very useful in skin cancer radiation treatment.

• Progress in Medical Physics
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• v.20 no.1
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• pp.1-6
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• 2009

For HDR intracavitary brachytherapy with ovoids and a tandem, we compared the dose discrepancy of treatment plans using two different Ir-192 sources (microSelectron, Varian) and generated on two different treatment planning systems (PLATO, BrachyVision). The treatment plans of ten patient treated from Oct. 2007 to Jan. 2008 were selected for these comparisons. For the comparison of dose calculation using different sources, the average discrepancies were $-0.91{\pm}0.09%$, $-0.27{\pm}0.07%$, $0.22{\pm}0.39%$, and $0.88{\pm}0.37%$ in total treatment time and at B-point and ICRU bladder and rectum reference point, respectively. Comparing the two systems, the average dose discrepancies between treatment planning programs were $-0.22{\pm}0.42%$, $-0.25{\pm}0.29%$, $-0.23{\pm}0.63%$, and $-0.17{\pm}0.76%$, and the average dose discrepancies between positioning methods (PLATO with film and BrachyVision with digitial image) were $-0.61{\pm}0.59%$, $-0.77{\pm}0.45%$, $-0.72{\pm}1.70%$, and $0.35{\pm}2.82%$ at A-point, B-point, and ICRU bladder and rectum reference points, respectively. The rectal dose discrepancies between two systems were reached 5.87%. The difference in the dwell position expected by each TPS are mainly affected by the differences in the positioning method in TPSs and have an effect on dose calculations of rectal and bladder located in AP direction.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.18 no.2
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• pp.122-128
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• 2007

This study aims to analyze the voices of the patients with voice disorders including vocal fold paralysis, vocal fold cyst and vocal nodule/polyp in the aspect of acoustic phonetics. This study intends to collect subsidiary acoustic data in order to make a speech treatment and an standardization of vocal disorders. Subjects and Methods: The subjects of this study were 64 adult patients who underwent indirect laryngoscopy and laryngostroboscopy, and were diagnosed as vocal fold paralysis, vocal fold cyst or vocal nodule/polyp. Experimental group consisted of 20 patients who were diagnosed as vocal fold paralysis, 21 patients who were diagnosed as vocal fold cyst and had the average age of 42.0 $({\pm}10.03)$ ; and 23 patients who were diagnosed as vocal nodule/polyp and had the average age of 40.9 $({\pm}13.75)$. For the methodology of this study, the patients listed above were asked to sit in a comfortable position at intervals of 10cm apart from the patient's mouth and a microphone, and subsequently to phonate a vowel sound /e/ for the maximum phonation time with natural tone and vocal volume then the sound was directly inputted on a computer. During recording, sampling rate was set to 44,100Hz and the 1-second area corresponding to stable zone except the first and the last stage of waveform of the vowel sound /e/ vocalized by the individual patients was analyzed. Results: First, there was no statistically significant difference in jitter and shimmer between vocal fold paralysis and vocal fold cyst, while there was highly statistically significant difference in them between vocal fold paralysis and vocal nodule/polyp. Second, looking into the mean values obtained from NNE, HNR and SNR results associated with noise ratio, the disease showing the most abnormal characteristics was vocal fold paralysis, followed by cyst and nodule/polyp in order. For NNE, there was statistically significant difference between vocal nodule/polyp, and cyst or paralysis. In other words, it was found that the NNE of vocal nodule/polyp was weaker than that of cyst or paralysis. Similarly, HNR and SNR also showed the same characteristics; there was statistically significant difference between vocal fold paralysis and vocal fold cyst or nodule/polyp, and HNR and SNR values of vocal fold paralysis were lower than those of vocal fold cyst or nodule/polyp. Conclusion: For vocal fold paralysis, the abnormal values of acoustic parameters associated with frequency, amplitude and noise ratio were statistically significantly higher than those of vocal fold cyst and nodule/polyp. This finding suggests that the voices of the patients with vocal fold paralysis are the most severely injured due to less stability of vocal fold movement, asymmetry and incomplete glottic closure. In addition, there was no statistically significant difference in the acoustic parameters of tremor among vocal fold paralysis, vocal fold cyst and vocal nodule/polyp. Further studies need to ascertain reasonable acoustic parameters with various vocal disorders as well as to clarify the correlation between acoustics-based objective tools and subjective evaluations.

• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.560-569
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• 1996

Background and Purpose : Standardized uptake value(SUV) has been used as a quantitative index for differentiating benign and malignant tumors with F-18-FDG PET In this study, we produced whole body parametric images of SUV(WBPIS) by body weight normalization, and validated the values by comparison with SUV's calculated with regional scans. Subjects and Methods : Whole body scans were followed by regional scans sequentially on 23 patients. In whole body study, transmission and emission scans were acquired for 2 minutes and 6 minutes for each bed position, respectively. In regional study, transmission and emission scans were acquired for 20 minutes. Measured and segmented/ smoothed attenuation correction were applied using these 2 min transmission scans in whole body studies. The effects of attenuation correction on SUVs were evaluated quantitatively using F-18 filled cylindrical phantom. The mean and peak SUVs obtained from WBPIS were compared with SUVs of the regional scans. Results : In phantom studies, with any method of attenuation correction using regional or whole body studies of phantom, SUVs were nearly consistent. In whole body scan, SUV obtained using measured attenuation correction method was a little higher than SUV of regional scan. SUV obtained using segmented/smoothed attenuation correction method was a little lower. In patient studies, WBPIS using segmented/smoothed attenuation correction method was much smoother and more readable. SUVs of WBPIS obtained with both methods of attenuation correction were well correlated with SUVs of regional scans(r=0.9). SUVs of WBPIS with measured attenuation correction method were 5% lower than SUVs of regional scans. SUVs of WBPIS with segmented/smoothed attenuation correction method were 10% lower than SUVs of regional scans. The differences of SUVs of WBPIS by the two attenuation correction methods were relatively small compared with the possible differences derived from biological characteristics of tumors. Conclusion : We concluded that WBPIS could be useful in the quantification of tumor as well as in localization of whole body lesions, which were often outside the field of view in regional scan. WBPIS made using segmented/smoothed attenuation correction method could be used in clinical routines and SUVs from attenuation corrected F-18-FDG PET could be used interchangeably with SUVs of regional studies.

• Journal of agricultural medicine and community health
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• v.38 no.2
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• pp.130-141
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• 2013

Objectives: The purpose of this study was to reconsider the necessity of stroke-related educational programs by investigating early symptoms of stroke that emergency medical technicians (EMTs) may experience. Methods: An interview survey was carried out, targeting all EMTs 298 people who were working at 119 fire safety centers and local units in Jeollabuk-do province, from April 1 to 30, 2011. An interviewer administered questionnaire was used to obtain data on ETMs' demographic characteristics, educational level on stroke, and awareness level about early symptoms of stroke and treatment-related characteristics of stroke patients. Results: The results showed that 63.2% of those surveyed had completed the required educational programs on stroke during the past year. The level of awareness about early symptoms of stroke and assessment of stroke patients' condition was relatively high for women, those who were 30 years under, low position people, emergency service practitioners, emergency medical technicians, and people who have completed education, respectively. It was also turned out that 82.8% of those surveyed took stroke patients to the nearest hospitals first so that they could receive appropriate treatment. The level of awareness about early symptoms of stroke and assessment of stroke patients' condition in people who have completed education were higher than non-complete. The level of awareness about early symptoms of stroke was positively correlated with confidence, satisfaction and appropriateness in treatment of stroke patients. Conclusions: These results strongly suggest that it is necessary to operate specialized educational programs to enhance EMTs' appropriate awareness of the early symptoms of stroke and assessment of stroke patient's condition.