• Korean Journal of Biological Psychiatry
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• v.5 no.2
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• pp.263-277
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• 1998

Conventional high-dose antipsychotics tend to result in more side effects, negative symptoms and dysphoria, and at the same time lower the cognitive function which is already impaired in most schizophrenics. Florid psychotic symptoms, negative symptoms and cognitive impairment greatly impede psychosocial performance and eventual reintegration into society. The reduction of symptom and the improvement of cognitive funtions and social skills are therefore central to the psychiatric rehabilitation process. The purpose of this study was to evaluate the dose-reduction effects of antipsychotics on chronic schizophrenics prescribed conventional high-dose antipsychotics more than 1,500mg equivalent of chlorpromazine. Fifty-one chronic schizophrenics who maintained high-dose antipsychotics for more than three months were randomly assigned to two groups : 20 patients comprised the dose-maintaining group and 31 patients made the dose-reduction group. Over a sixteen weekperiod Positive and Negative Syndrome Scale(PANSS), Extrapyramidal Symptom(EPS), Nurses' Observation Scale for Inpatient Evaluation(NOSIE-30), Continuous Performance Test(CPT), Quality of Life(QOL), and haloperidol/reduced haloperidol blood levels were determined at the base line and after 2, 4, 6, 8, 12, 16 weeks to evaluate the dose reduction effects of high-dose antipsychotics. The results were as follows : 1) Dose-reduction is highly effective in reducing positive and negative symptoms, and general psychopathology. Effects were most prominent at 8, 12, 16 weeks. Among the dose reduction group, positive symptoms in positive symptom group and negative symptoms in negative symptom group were more reduced. 2 Extrapyramidal symptoms showed no significant difference between two groups. But the EPS was reduced time after time within two groups. 3) Hit rates of Continuous Performance Test, which indicate attentional capacity, increased significantly after dose reduction. 4) Haloperidol and reduced haloperidol blood levels decreased until the 4th week, after which they were constant. 5) Total scores of Nurses' Observation Scale for Inpatient Evaluation were unchanged between the two groups. But among the indices, social interest and personal neatness were improved in the dose-reduction group and retardation was aggrevated in the dose-maintaining group. 6) Total quality of life scores were unchanged between two groups. But in the dose maintaining group, satisfaction scores of attention, autonomy, and interpersonal relationship decreased progressively. These findings suggest that the dose reduction of antipsychotics for chronic schizophrenics on programs of high-dose antipsychotics were effective. Dose reduction should therefore be implemanted to spread the rehabilitation and improve quality of life for chronic schizophrenics.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.357-366
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• 1998

Brachytherapy is an essential part of radiotherapy for uterine cervical cancer. The low dose rate (LDR) regimen has been the major technique of intracavitary therapy for cervical cancer. However, there has been an expansion in the last 20 years of high dose rate (HDR) machines using Ir-192 sources. Since 1979, HDR brachytherapy has been used for the treatment of uterine cervical cancer in Korea. The number of institutions employing HDR has been increasing, while the number of low dose rate system has been constant. In 1995, there was a total 27 HDR brachytherapy units installed and 1258 cases of patients with cervical cancer were treated with HDR Most common regimens of HDR brachytherapy are total dose of 30-39 Gy at point A with 10-13 fractions in three fractions per week. 24-32 Gy with 6-8 fractions in two fractions per week, and 30-35 Gy with 6-7 fractions in two fractions per week. The average fractionation regimen of HDR brachytherapy is about 8 fractions of 4.1 Gy each to Point A. In Korea, treatment results for HDR brachytherapy are comparable with the LDR series and appears to be a safe and effective alternative to LDR therapy for the treatment of cervical carcinoma. Studies from the major centers report the five-year survival rate of cervical cancer as. 78-86$\%$ for Stage 1, 68-85$\%$ for stage 11, and 38-56$\%$ for Stage III. World-wide questionnaire study and Japanese questionnaire survey of multiple institutions showed no survival difference in any stages and dose-rate effect ratio (HDR/LDR) was calculated to be 0.54 to 0.58. However the optimum treatment doses and fractionation schemes appropriate to generate clinical results comparable to conventional LDR schemes have yet to be standardized. In conclusion, HDR intracavitary radiotherapy is increasingly practiced in Korea and an effective treatment modality for cervical cancer. To determine the optimum radiotherapy dose and fractionation schedule, a nation-wide prospective study is necessary in Korea. In addition, standardization of HDR application (clinical, computer algorithms, and dosimetric aspects) is necessary.

• Journal of Pharmaceutical Investigation
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• v.5 no.2
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• pp.51-56
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• 1975

In the course of the investigations on drug metabolism and drug disposition in man, it has been noted that there are often rather striking individual differences in the response to drugs and in the ability to metabolize and dispose of drugs. Some of the person-to-person differences are due to environmental factors, but some have clearly demonstrated to be genetically determined. This report determined the rate of acetylation and some constants of sulfa-methizole to korean. The results are as follows: The overall removal rate of drug from the body is 0.572(k, $hr^{-1}$) the rate constant for acetylation, 0.222($k_2$, $hr^{-1}$) the rate constant for excretion of unchanged drug, 0.350($k_3$, $hr^{-1}$) and the faction of a dose ultimately excreted in the urine as unchanged drug is 0.677. And this report determined the optimal time to make a single blood level determination after an oral dose of the drug and obtain a reasonable index of the rate of sulfamethizole metabolism. The resulting data(sulfamethizole levels at 5 hours after drug administration) clearly established bimodality even though only about 106 subjects were tested.

• Journal of Radiation Protection and Research
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• v.16 no.2
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• pp.41-54
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• 1991

This paper aimed to analyse dose sensitivity to the controllable parameters of indoor radon $(^{222}Rn)$ and its decay products (Rn-D) by applying the input~output linear system theory. Physical behaviors of $^{222}Rn\;&\;Rn-D$ were analyzed in terms of $(^{222}Rn)$ gas -generation, -migation and -infiltration to indoor environments, and the performance output-function, i. e. mean dose equivalent to Tracho-Bronchial (TB) lung region, was assessed to the following extented ranges of the controllable paramenters; a) the ventilation rate $constant({\lambda}_v)\;:\;0{\sim}50[h^{-l}].\;b)$ the attachment rate $constant({\lambda}_a)\;:\;0{\sim}500[h^{-l}].\;c)$ the unattached-deposition rate constant (${\lambda}^u_d)\;:\;0-50[h-l]$. A linear input-output model was reconstructed from the original models in literatures, as follows, which was modified into the matrices consisting of 111 nodal equations; a) indoor $^{222}Rn\;&\;Rn-D$ Behaviour; Jacobi-Porstendoerfer-Bruno model.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.7
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• pp.548-554
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• 2003

This study alms to investigate the dynamic properties of express buses in the very low frequencies which cause motion sickness Incidence. Since passengers often use express buses for long distance traveling. it is a critical point whether the ride give rise to motion sickness or not. In the study accelerations at the three Points on the floor of the six test vehicles were measured during the driving at constant speeds. By applying the frequency weighting corves suggested in ISO 26.31-1, the Physical quantity of accelerations were changed into the perceptual amount used to judge quantitatively the incidence of motion sickness. Motion sickness dose values were calculated from the frequency weighted time history of acceleration signals, and compared between the vehicles, driving conditions. and the seat positions in the bus. During the 50 minutes' driving on the public road and high ways. the vomiting incidence ratios were seen to range from 0.4 to 0.8 ％. which is equivalent to 2.4 to 4.8 ％ for 5 hours' driving. Unlike the very smooth road conditions considered in this work, motion sickness dose values encountered in real situations are expected to increase.

• Journal of Radiation Protection and Research
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• v.39 no.4
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• pp.182-186
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• 2014

Recently, the use of panoramic radiography has shown a constant increase, and significant research is underway. However, radiation exposure attracts less attention in dental radiography than in other types of radiography. We used an OSLD for measurement of the entrance skin dose in eyeballs and the thyroid region, both of which are not covered by examinations but are included in radiographical regions and are sensitive to radiation, as well as orally in Incheon and reported the results. The entrance skin dose was 0.0282 mSv on average for the oral region, and 0.0259 mSv on average for the eyeball, and 0.0261mSv on average, for thyroid gland. While there is no proper shielding method for the eyeball, a thyroid protector is not used by most hospitals and most hospitals are equipped with an apron and a thyroid protector separately; thus, it is necessary to use an integration of an apron and a thyroid protector and medical device manufacturers need to develop a method for controlling the length of the slit in the slit-type area of radiation occurrence in order to reduce unnecessary exposure.

• Progress in Medical Physics
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• v.24 no.4
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• pp.230-236
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• 2013

Our purpose is to present a novel technique for delivering craniospinal irradiation in the supine position using a perfect match, field-in-field (FIF) intrafractional feathering, and simple forward-optimization technique. To achieve this purpose, computed tomography simulation was performed with patients in the supine position. Half-beam, blocked, opposed, lateral, cranial fields with a collimator rotation were matched to the divergence of the superior border of an upper-spinal field. Fixed field parameters were used, and the isocenter of the upper-spinal field was placed at the same source-to-axis distance (SAD), 20 cm inferior to the cranial isocenter. For a lower-spinal field, the isocenter was placed 40 cm inferior to the cranial isocenter at a constant SAD. Both gantry and couch rotations for the lower-spinal field were used to achieve perfect divergence match with the inferior border of the upper-spinal field. A FIF technique was used to feather the craniospinal and spinal-spinal junction daily by varying the match line over 2 cm. The dose throughout the target volume was modulated using the FIF simple forward optimization technique to obtain homogenous coverage. Daily, image-guided therapy was used to assure and verify the setup. This supine-position, perfect match craniospinal irradiation technique with FIF intrafractional feathering and dose modulation provides a simple and safe way to deliver treatment while minimizing dose inhomogeneity.

• Progress in Medical Physics
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• v.11 no.2
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• pp.131-139
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• 2000

We designed high dose rate Ir-192 source which was prepared for substitute the Co-60 source in Ralstron unit (Simatsu, Japan) which is supplied for cervical cancer treatment. The source dimension is 1.5 mm in a diameter and 1.5mm thickness of cylinder and encapsulated with 3 mm diameter of stainless steel(SUS316L) to substituted for the Co-60 source size. The Ir-192 source was prepared the dose model for tissue dose computation through the experimental determination of apparent activity and applied the empirical tissue correction factors extended to 20cm distance. The tissue dose model was applied the 4.69 R/cm-mCi-hr gamma constant and the ratio of energy absorption coefficient of water to that of air showed 1.112 include filteration of the self-absorptions. In this experiments, we prepared the dose computation software to clinical usefulness.

• The Journal of Korean Society for Radiation Therapy
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• v.10 no.1
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• pp.88-93
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• 1998

Multileaf collimator is essential equipment in conformal radiation therapy, however the use is limitted by increase of penumbra width and undulating dose distribution at the field edge. The purpose of this study is to improve the penumbra and dose distribution in the multileaf collimator field edge. Measurement were performed with X-omat V film in solid water phantom using 6MV photon beam from Siemens linear accelerator. All the measurement were made along the central axis of $5{\times}5cm,\;10{\times}10cm$ circular field for constant SSD of 100 cm. To improve the penumbra and dose distribution collimator was rotated by 15 degrees from 0 to 90 degrees (collimator rotation method) and center was shifted to the longitudinal direction by fourth of lead width (center shift method). We compare the penumbra and dose distribution at the field edge to alloy block. Dose distribution and penumbra width at the feild edge of MLC showed undulated dose pattern and increased penumbra compared with alloy block. However, in the collimator rotation method and center shift method we abtained simular results with alloy block. Through the study we expected that clinical use of MLC will be increase.

• The Journal of Korean Society for Radiation Therapy
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• v.11 no.1
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• pp.6-10
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• 1999

The field size can be beam output, therefore MonitorUnit can be varied due to field size dependence The purpose of this study is to evaluate and compare the dose variation according to exchange of collimator The measurements were perfomed with Wellhofer dosimetry system(water phantom. ion chamber. electrometer. system controller. build up cap. etc)and two types of linear accerlerator (Mevatron KD, MevatronMX) Scatter can be affected to field size dependence and scatter correction is separated into collimator and phantom components, scatter components can affect by exchanging of collimator Measurements of collimator scatter factor(Sc) was done in air with build up cap. 1)Square field (5cm2 to 40cm2) was measured 2)and then keeping the upper jaw constant at loom and varing lower jaw from 5cm to 40cm, 3)keeping the lower jaw constant at 10cm and varing upper jaw from 5cm to 40cm Measurements of total scatter factor(Scp) was done in water at Dmax as the procedure of collimator scatter factor measurements in water Dmax The total scatter factors were obtained to the following equation(Sp=Scp/Sc) The measured data is normalized to the data of reference field size($10{\times}10$), rectangular field is inverted to equivalent field to compare three field size data As the collimator setting is varied, the output was changed In conclusion, the error was obtained small but it must be eliminated if we intend to reach the common stated goal of $5\%$ overall uncertainty in dose determination