• Radiation Oncology Journal
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• v.10 no.1
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• pp.107-113
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• 1992

Increasing frequency of skin cancer, mycosis fungoides, Kaposi's sarcoma etc, it need to treatment dose planning for total skin electron beam (TSEB) therapy. Appropriate treatment planning for TSEB therapy is needed to give homogeneous dose distribution throughout the entire skin surface. The energy of 6 MeV electron from the 18 MeV medical linear accelerator was adapted for superficial total skin electron beam therapy. The energy of the electron beam was reduced to 4.2 MeV by a $0.5\;cm\times90\;cm{\times}180\;cm$ acryl screen placed in a feet front of the patient. Six dual field beam was adapted for total skin irradiation to encompass the entire body surface from head to toe simultaneously. The patients were treated behind the acryl screen plate acted as a beam scatterer and contained a parallel-plate shallow ion chamber for dosimetry and beam monitoring. During treatment, the patient was placed in six different positions due to be homogeneous dose distribution for whole skin around the body. One treatment session delivered 400 cGy to the entire skin surface and patients were treated twice a week for eight consecutive weeks, which is equivalent to TDF value 57. instrumentation and techniques developed in determining the depth dose, dose distribution and bremsstrahlung dose are discussed.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.319-321
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• 2004

The average glandular dose (AGD) is determined by the breast entrance skin exposure, x-ray tube target material, beam quality (half-value layer), breast thickness, and breast composition. Almost breast cancer always arises in glandular breast tissue. As a result, the average radiation absorbed dose to glandular tissue is the preferred measure of the radiation risk associated with mammography. If the normalized average glandular dose is known, the average glandular dose can be computed from the product of the normalized average glandular dose and breast entrance skin exposure. In this study, AGD was calculated by the breast thickness and various x-ray energy (HVL) in 50% glandular 50% adipose breast by Mo.-Rh. assembly. AGD is 84 mrad in compressed 5 cm breast. These results show that as increasing the breast thickness, dose also increases. But as increasing the x-ray tube voltage, dose decreases because of high penetrating ratio through the object. But high tube voltage is reducing the subject contrast. From this result, we have to consider the trade-off between subject contrast of image and dose to the patient and choose proper x-ray energy range.

• Progress in Medical Physics
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• v.27 no.4
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• pp.220-223
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• 2016

Generally, it is recommended that the dosimetric effect of carbon fiber couch should be considered especially for an intensity-modulated therapy with a large portion of monitor units from posterior angles. Even a flattening filter free (FFF) beam has been used for stereotactic body radiation therapy (SBRT), the effect of carbon fiber couch for FFF beam is not well known. This work is an effort to evaluate the dosimetric effect of carbon fiber couch for flattened and FFF beam of Elekta linac empirically. The absorbed doses were measured with Farmer type chamber and water-equivalent phantoms with and without couch. And differences of the absorbed doses between with and without couch defined as "couch effect". By comparing calculated dose in treatment planning system (TPS) with measured dose, the optimal density of couch was evaluated. Finally, differences on patient's skin dose and target dose by couch were evaluated in TPS. As a result, the couch effect for 6 and 10 MV flattened beam were -2.71% and -2.32%, respectively. These values were agreed with provided data by vendor within 0.5%. The couch effect for 6 and 10 MV FFF beam were -3.75% and -2.80%, respectively. The patient's skin dose was increased as 18.6% and target dose was decreased as 0.87%, respectively. It was realized that the couch effect of FFF beam was more severe than that of flattened beam. Patient's skin dose and target dose were changed by the couch effect.

• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.75-81
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• 2016

The recent radiation therapy field can provide treatment which guarantees a high degree of accuracy, due to patient set-up using various image guided radiation therapy(IGRT) instruments. But the additional absorbed dose to patient's normal tissues is increasing. Therefore, this study measured the absorbed dose to surrounding normal tissues which is caused by patient set-up using OBI, CBCT, ExacTrac, among various IGRT instruments. The absorbed dose to the head, the chest, the abdomen, and the pelvis from CBCT was 12.57 mGy, 20.82 mGy, 82.93 mGy, and 52.70 mGy, respectively. Also, the absorbed dose from OBI and ExacTrac ranged from 0.76 to 8.58 mGy and from 0.14 to 0.63 mGy, respectively. As a result, CBCT's absorbed dose was far higher than other instruments. CBCT's surface dose was far higher than others, too, but OBI's entrance skin dose was almost the same as CBCT's.

• Korean Journal of Biological Psychiatry
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• v.16 no.4
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• pp.266-270
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• 2009

Adverse drug reactions are very common in clinical practice, and skin is one of the most frequent organs for adverse drug reactions. We report a case of a 71-year-old male patient who developed skin eruptions after switching formulation of quetiapine immediate release(IR) to quetiapine extended release(XR). He had been taking quetiapine IR(400mg/day) for treatment of manic episode which was developed one year ago. The patient showed great improvement of symptoms after taking quetiapine IR for about one year, thus dosage of medication was reduced to 50mg/day on the average. Unfortunately dose reduction has tended to worsen symptoms, so dose of quetiapine was increased again to 200mg/day with formulation changes to XR. Two days after he took new formulation, erythematous papules were occurred over his anterior neck and ventral side of left wrist. As he stopped quetiapine XR, the skin lesions gradually subsided. And he was successfully treated with readministration of quetiapine IR without any skin lesions.

• Journal of radiological science and technology
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• v.15 no.1
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• pp.89-97
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• 1992

X-ray quality is identified numerically by half value layer(H.V.L) and the HVL is affected by the kVp and the amount of filtration in the useful beam. X-ray quality evaluated by H.L.D is influenced by kVp and filtration. Author had several experiments with phantom in diameter of 8 cm normal adult chest, for reduction of radiation dose of the patients in diagnostic radiology and got some results. 1. H.V.L is increased the thicker the filter and the higher the kVp. 2. If the kVp is increased from 60 to 120, the skin dose can be reduced as 34%(Skin dose of 60 kVp with 4 mmAl filter : 100%). 3. If the 4 mmAl filter with 60 kVp is added to x-ray tube, skin dose can be reduced as 23% than no filter. 4. Therefore high kVp and filtration can increase output to input dose ratio and 120 kVp and 4 mmAl filter were most effective for reduction of patient dose in chest radiography.

• The Journal of the Korea Contents Association
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• v.10 no.2
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• pp.258-267
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• 2010

This interest in radiation exposure makes increasing doctor's awareness and knowledge of radiation dose in patients during X-ray test important in reducing patient's uneasiness. However, very few facilities are equipped with measurement instruments. Therefore, an intensive study to find out patient dose using computational method has been initiated. This study used special features of the bit system and NDD-M and directly measured the output dose of diagnostic X-ray instruments used in Korea to create tables. Two different methods were found to be adequate when applied to cases when X-ray outputs were both known and unknown, and comparative experiments with real measurement doses were carried out. Presented methods were found to provide more accurate results compared to the bit system and NDD-M. Therefore, patient dose during clinical trials were found to be more easily acceptable to medical personnel in the radiation field in terms of radiation exposure and reduction of medical X ray dose.

• Journal of radiological science and technology
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• v.21 no.1
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• pp.29-34
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• 1998

The purpose of simple abdomen erect projection is to see the fluid level which indicates gastrointestinal ileus or free air due to perforation. we do not have to insist on low kVp technique in simple abdomen erect position as long as we can detect the fluid level and free air shadow. Therefore, the author tried to decrease patient dose by high kVp technique and to improve the image quality due to motion artifact by reduction of exposure time. [Methods] Experiment 1. * screen/film SRO1000/HRH * exposure factor : $140\;kvp{\pm}5\;kv$ with added filters, 200 mA, 0.01 sec * phantom : Acryles : 15.0 cm(equivalent to 17 cm body thickness) 17.5 cm(equivalent to 21 cm body thickness) 20.0 cm (equivalent to 25 cm body thickness) With the exposure factor for same film density($D=0.8{\pm}0.1$) and with the materials above, we tried to find out entrance skin dose and gonad dose for both male and female. Experiment 2. Burger's phantom radiography were checked to see whether there was any change of image quality according to the kVp and the added filters. Experiment 3. Using rotating meter(self made), we examined the motion artifact and the exposure time limitation. [Results and conculution] 1. Using high voltage technique of 140 kVp with added filter, Skin dose, testicle dose and ovary dose decrease to 89.3%, 47% and 71.4% respectively compare to 70 kVp technique, 2. No great changes of Burger's phantom image has detected as from 70 kVp to 140 kVp and the air hole size of Burger's phantom over 0.028 cc(Diameter 3 mm, hight 4 mm) can be distinghished. 3. 0.01 sec(1 pulse) exposure time is possible in the single phase full wave rectification that why we can quitely reduce the unsharness caused by patient's movement.

• Journal of Radiation Protection and Research
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• v.36 no.2
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• pp.86-92
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• 2011

This study used the optically stimulated luminescence dosimeters (OSLDs), recently, received the revaluation of usefulness in vivo dosimetry, and the diode detecters to measure the skin dose of patient with the rectal cancer. The measurements of dose delivered were compared with the planned dose from the treatment planning system (TPS). We evaluated the clinical application of OSDs in radiotherapy. We measured the calibration factor of OSLDs and used the percent depth dose to verified, also, we created the three point of surface by ten patients of rectal cancer to measured. The calibration factors of OSLD was 1.17 for 6 MV X-ray and 1.28 for 10 MV X-ray, demonstrating the energy dependency of X-ray beams. Comparison of surface dose measurement using the OSLDs and diode detectors with the planned dose from the TPS, The skin dose of patient was increased 1.16 ~ 2.83% for diode detectors, 1.36 ~ 2.17% for OSLDs. Especially, the difference between planned dose and the delivery dose was increased in the perineum, a skin of intense flexure region, and the OSLDs as a result of close spacing of measuring a variate showed a steady dose verification than the diode detecters. Therefore, on behalf of the ionization chamber and diode detecters, OSLDs could be applied clinically in the verification of radiation dose error and in vivo dosimety. The research on the dose verification of the rectal cancer in the around perineal, a surface of intense flexure region, suggest continue to be.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.299-308
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• 2012

To perform patient dose surveys in major interventional radiography procedures as a mean of inter-institutional comparison and of establishing reference dose levels with the ultimate goal of optimizing patient doses in the field of interventional radiography. We reviewed international patient dose survey data in the literature and measured patient dose in major interventional radiography procedures (TACE, AVF, PTBD, TFCA, GDC embolization). ESD(Entrance Skin Dose) was measured using TLD chips attached to the patient skin and ED(Effective Dose) was calculated using angiography unit-derived DAP. A survey of patient dose in interventional radiography procedures were also performed with a questionnaire for interventional radiologists and we proposed a guideline for optimizing patient doses in the field of interventional radiology. The patient dose survey data in interventional radiography procedures were very rare in literature compared with those in diagnostic radiography procedures. In TACE, the mean ED was 25.43 mSv and the mean ESD was 511.75 mGy. The mean ED of TACE was not high, but the cumulative dose should be checked, due to longer procedure TACE. In TFCA, the mean ED was 22.6 mSv and it was relatively high compared with data of other countries. In GDC embolization, the mean ED was not available, because GDC embolization was performed with old Image-Intensifier-type unit and there has no unit-installed ionization chamber. Also, the mean ESD of GDC embolization was up to 2,264 mGy and further studies are needed to calculate the net ED of GDC embolization. Patient dose occurred during interventional radiography procedures are high related with the difficulty of the procedure, fluoroscopy time, the number of angiographies and the treatment protocol. Therefore, continuous education and efforts should be made to optimize the patient dose in the field of interventional radiology.