• Journal of radiological science and technology
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• v.32 no.1
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• pp.39-43
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• 2009

The medical diagnostic examination using ionizing radiation has improved the patients' life and brought revolution in medical examination along with the mechanical development. However, the development of medical imaging systems has also been the reason to increase the patients' exposure for ionizing radiation. ICRP recommends that each country adopts diagnostic reference levels depending on regional and national situations. The Korea Food & Drug Administration suggested the dosimetry measurement guideline for patients in 2007. Nonetheless, in reality, it is hard to know the skin dose of the patients when applying a x-ray since there is no radiation dosimeter in most of clinical situation. Therefore, this study sets a program based on the bit system to figure out easily the skin dose of a patients using MS Excel program in the PC setting. The results showed 10% better outcome.

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.157-162
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• 2009

Radioactive medicines are used a lot owing to the increase of a PET-CT examination using glucose metabolism useful for the early diagnosis of diseases. Therefore, the spatial dose that is generated from patients and their surroundings causes the patients' guardians and health professional to be exposed to radiation. However, they get unnecessarily exposed to radiation because medical institutions lack in space for isolation and recognition of the examination. This research intended to examine the spatial dose rates by measuring the dose emitted from the patient for 48 hours to whom F-18 FDG was administered. The spatial dose rates that were measured 100cm away from the patient's body after F-18 FDG was injected were $65.88{\mu}$Sv/hr at 60-minute point, $45.13{\mu}$Sv/hr at 90-minute point, $9.88{\mu}$Sv/hr at 6-hour point, and $1.24{\mu}$Sv/hr at 12-hour point. When the dose that the guardian and health professional got was converted into the annual(240-day working) accumulative dose, it was examined that the guardian received 81.56 mSv/yr and health professional received 49.36mSv/yr. In addition, the result has revealed that the dose that the patient received from one time of PET-CT examination was 3.75mSv/yr, which is 1.5 times more when compared with the annual natural radiation exposure dose.

• Progress in Medical Physics
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• v.30 no.4
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• pp.150-154
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• 2019

The objective of this study is to monitor the radiation doses delivered to a cardiac implantable electronic device (CIED) by comparing the absorbed doses calculated by a commercial treatment planning system (TPS) to those measured by an in vivo dosimeter. Accurate monitoring of the radiation absorbed by a CIED during radiotherapy is necessary to prevent damage to the device. We conducted this study on three patients, who had the CIED inserted and were to be treated with radiotherapy. Treatment plans were generated using the Eclipse system, with a progressive resolution photon optimizer algorithm and the Acuros XB dose calculation algorithm. Measurements were performed on the patients using optically stimulated luminescence detectors placed on the skin, near the CIED. The results showed that the calculated doses from the TPS were up to 5 times lower than the measured doses. Therefore, it is recommended that in vivo dosimetry be conducted during radiotherapy for CIED patients to prevent damage to the CIED.

• Journal of radiological science and technology
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• v.38 no.4
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• pp.483-489
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• 2015

DICOM (Digital Imaging and Communications in Medicine) standards are generally introduced as de facto and de jure standards in modern medical imaging devices to store and to transmit medical image information. DICOM Dose Structured Report (DICOM dose SR) is implemented to report radiation exposure information in image acquiring process. and DIOCM Modality Performed Procedure Step (DICOM MPPS) is also partly used to report this exposure with the information in its DICOM tag. This article is focused on three type of radiation exposure information of DICOM standards, 1) DICOM dose SR, 2) DICOM MPPS and 3) Radiation Exposure Monitoring(REM) profile by Integrating the Healthcare Enterprise(IHE), to study on radiation exposure reporting. Healthcare facility and its staff of medical imaging related to radiation exposure should have a deep understanding of radiation exposure, and it required a standards to enhance the quality control of medical imaging and the safety of patients and staffs. Staff member have to pay attention on radiation exposures and controling processes from the purchasing stage of X-ray devices.

• Radiation Oncology Journal
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• v.21 no.4
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• pp.276-282
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• 2003

Purpose: Although high-dose-rate intracavitary radiotherapy (HDR ICR) has been used in the treatment of cervical cancer, the potential for increased risk of late complication, most commonly in the rectum, is a major concern. We have previously reported on 136 patients treated with HDR brachytherapy between 1995 and 1999. The purpose of this study is to upgrade the previous data and confirm the correlation between late rectal complication and rectal dose in cervix cancer patients treated with HDR ICR. Materials and Methods: A retrospective analysis was peformed for 222 patients with cevix cancer who were treated for curative intent with external beam radiotherapy (EBRT) and HDR ICR from July 1995 to December 2001. The median dose of EBRT was 50.4 (30.6$\~$56.4) Gy with a daily fraction size 1.8 Gy. A total of six fractions of HDR ICR were given twice weekly with fraction size of 4 (3$\~$5.5) Gy to A point by Iridium-192 source. The rectal dose was calculated at the rectal reference point using the barium contrast criteria. in vivo measurement of the rectal dose was peformed with thermoluminescent dosimeter (TLD) during HDR ICR. The median follow-up period was 39 months, ranging from 6 to 90 months. Results: Twenty-one patients (9.5$\%$) experienced late rectal bleeding, from 3 to 44 months (median, 13 months) after the completion of RT. The calculated rectal doses were not different between the patients with rectal bleeding and those without, but the measured rectal doses were higher in the complicated patients. The differences of the measured ICR rectal fractional dose, ICR total rectal dose, and total rectal biologically equivalent dose (BED) were statistically significant. When the measured ICR total rectal dose was beyond 16 Gy, when the ratio of the measured rectal dose to A point dose was beyond 70$\%$, or when the measured rectal BED was over 110 Gy$_{3}$, a high possibility of late rectal complication was found. Conclusion: Late rectal complication was closely correlated with measured rectal dose by in vivo dosimetry using TLD during HDR ICR. If data from in vivo dosimetry shows any possibility of rectal bleeding, efforts should be made to reduce the rectal dose.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.5
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• pp.2573-2577
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• 2016

Objective: The aim of this study was to determine a method of dose prescription that minimizes normal tissue irradiation outside the planning target volume (PTV) during stereotactic body radiotherapy (SBRT) for patients with non-small cell lung cancer. Methods: Previous research and patients with typical T1 lung tumors with peripheral lesions in the lung were selected for analysis. A PTV and several organs at risk (OARs) were constructed for the dose calculated; six treatment plans employing intensity modulated radiotherapy (IMRT) were produced, in which the dose was prescribed to encompass the PTV, with the prescription isodose level (PIL) set at 50, 60, 70, 80, 90 or 95% of the isocenter dose. Additionally, four OARs around the PTV were constructed to evaluate the dose received in adjacent tissues. Results: The use of higher PILs for SBRT resulted in improved sparing of OARs, with the exception of the volume of lung treated with a lower dose. Conclusions: The use of lower PILs is likely to create significant inhomogeneity of the dose delivered to the target, which may be beneficial for the control of tumors with poor conformity indices.

• Journal of Korean Neurosurgical Society
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• v.42 no.3
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• pp.159-167
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• 2007

Vestibular schwannoma (VS) is a benign tumor typically originated in the schwann cell of vestibular nerve and usually accompany hearing symptom. Microsurgical removal and radiosurgery have a great role for the treatment of VS. Recently radiosurgery has been considered as an alternative or primary treatment for VS with the tremendous increase of patients who were treated with gamma knife radiosurgery (GKS) though microsurgery still takes the premier. By many published results, it is proved that GKS is a effective and noninvasive technique for VS, especially small sized tumors with satisfactory tumor control rate. The authors assumed that GKS can be expected to achieve satisfactory tumor control rate for small VS under 5cc in volume. A major interest regarding radiosurgery nowadays is to determine the optimal radiation dose for hearing preservation to improve the quality of life of patients. The more high radiation dose are used for effective tumor growth control, the more radiation-related complications like as hearing deficit, the impairment of other cranial nerve function are increased. Since 1990's the mean radiation dose for tumor margin was more than 18 Gy, but there were high complication rate in spite of good tumor growth control. After the year of 2000, under the influence of advanced neuro-imaging techniques and radiosurgical planning system which enable clinicians to do more precise planning, marginal dose for VS has been decreased to 12-13 Gy and the radiation-related complications has been reduced. But because there may be a unexpected radiation induced complications as time goes by after the latency period, optimal radiation dose for VS should be established on the basis of more long term follow-up observation.

• Radiation Oncology Journal
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• v.38 no.1
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• pp.52-59
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• 2020

Purpose: To evaluate and compare the feasibilities of magnetic resonance (MR) image-based planning using synthetic computed tomography (sCT) versus CT (pCT)-based planning in helical tomotherapy for prostate cancer. Materials and Methods: A retrospective evaluation was performed in 16 patients with prostate cancer who had been treated with helical tomotherapy. MR images were acquired using a dedicated therapy sequence; sCT images were generated using magnetic resonance for calculating attenuation (MRCAT). The three-dimensional dose distribution according to sCT was recalculated using a previously optimized plan and was compared with the doses calculated using pCT. Results: The mean planning target volume doses calculated by sCT and pCT differed by 0.65% ± 1.11% (p = 0.03). Three-dimensional gamma analysis at a 2%/2 mm dose difference/distance to agreement yielded a pass rate of 0.976 (range, 0.658 to 0.986). Conclusion: The dose distribution results obtained using tomotherapy from MR-only simulations were in good agreement with the dose distribution results from simulation CT, with mean dose differences of less than 1% for target volume and normal organs in patients with prostate cancer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.2118-2123
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• 2010

Korean individual occupational exposure control is focused on the retrospective service to the over-exposed person by the reading of personal dosimeter. Since the radiophamaceuticals using in the nuclear medicine department are uncontained radiation sources, the potential exposure at working environment is very high. Moreover, a patient remains radioactive for hours or even days after the administration of a radiopharmaceutical for diagnosis or treatment. Thus, the proper working environmental exposure control must be established and executed to protect not only the affiliated employees, but also guardians accompanying patients and temporarily visiting public from the exposure by the patients. Japanese radiation protection law regulates working environmental radiation exposure by regularly measuring and filing the environmental dose for years. This study was aimed at measuring working environmental radiation dose in the nuclear medicine department of an university hospital located in Daejeon, Korea. We measured the accumulation radiation dose in air at 8 locations in the nuclear medicine department by using the same method as in Japan with glass dosimeters. The highest dose rate, 0.23 mSv per month, was measured at the waiting room, and the second one is at reception desk. Even though the doses were lower than the Korean constraint dose rate (0.3 mSv/week) at the boundary of the radiation controlled area, it was over the dose limit of public (1 mSv/y) and environment (0.25 mSv/y). Conclusionally, it was found that the new or additional procedure was necessary to less the exposure dose to the receptionist and guardians by the environmental radiation dose in the nuclear medicine department.

• Radiation Oncology Journal
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• v.1 no.1
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• pp.103-109
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• 1983

47 out of 56 cases of intact uterine cervix cancer treated by radiation at the Hanyang University Hospital were followed 18 months or more after treatment. (7 patients died before 18 months, 2 cases lost to follow-up). Age distribution reveal 5 cases in 30's, 18 cases in 40's, 17 cases in 50's, 7 cases in 60's. Histologically, all cases were squamous cell type except one case of adenocarcinoma. 1. 45 cases were treated by combined external Co-60 irradiation and intracavitary irradiation by Cs-137 small sources. 1 case was treated by external irradiation only, and 1 case by intracavitary only. 2. Rectal injuries were observed in 13 cased (27.6%), 4 cases in Grade 1, 8 cased in Grade 2 and 1 cases in Grade 3 which needed surgical management. 3. Average intervals of rectal injury following treatment was 9.2 months varying from 5 to 15 months. 4. Relation between rectal injury and point A dose reveal 6 cases between 7000-7999 rad and 6 cases between 8000-8999 rad and 1 case above 9000 rad. Even though there is no direct relation between point A dose and rectal injury, it is expected that rectal injury increases as point A dose increase. 5. In the normal condition, rectal injury can't be attributed to one major cause. Radiation dose, small source distribution, general condition of patients, local anatomy of the individual patient, history of PID and previous surgery, all play complex roles.