• Progress in Medical Physics
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• v.30 no.1
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• pp.32-38
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• 2019

Purpose: The objective of this study is to evaluate the geometrical accuracy of a patient-specific bolus based on a three-dimensional (3D) printed mold and casting method. Materials and Methods: Three breast cancer patients undergoing treatment for a superficial region were scanned using computed tomography (CT) and a designed bolus structure through a treatment planning system (TPS). For the fabrication of patient-specific bolus, we cast harmless certified silicone into 3D printed molds. The produced bolus was also imaged using CT under the same conditions as the patient CT to acquire its geometrical shape. We compared the shapes of the produced bolus with the planned bolus structure from the TPS by measuring the average distance between two structures after a surface registration. Results and Conclusions: The result of the average difference in distance was within 1 mm and, as the worst case, the absolute difference did not exceed ${\pm}2mm$. The result of the geometric difference in the cross-section profile of each bolus was approximately 1 mm, which is a similar property of the average difference in distance. This discrepancy was negligible in affecting the dose reduction. The proposed fabrication of patient-specific bolus is useful for radiation therapy in the treatment of superficial regions, particularly those with an irregular shape.

• Progress in Medical Physics
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• v.28 no.1
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• pp.33-38
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• 2017

Creating individualized build-up material for superficial photon beam radiation therapy at irregular surface is complex with rice or commonly used flat shape bolus. In this study, we implemented a workflow using 3D printed patient specific bolus and describe our clinical experience. To provide better fitted build-up to irregular surface, the 3D printing technique was used. The PolyLactic Acid (PLA) which processed with nontoxic plant component was used for 3D printer filament material for clinical usage. The 3D printed bolus was designed using virtual bolus structure delineated on patient CT images. Dose distributions were generated from treatment plan for bolus assigned uniform relative electron density and bolus using relative electron density from CT image and compared to evaluate the inhomogeneity effect of bolus material. Pretreatment QA is performed to verify the relative electron density applied to bolus structure by gamma analysis. As an in-vivo dosimetry, Optically Stimulated Luminescent Dosimeters (OSLD) are used to measure the skin dose. The plan comparison result shows that discrepancies between the virtual bolus plan and printed bolus plan are negligible. (0.3% maximum dose difference and 0.2% mean dose difference). The dose distribution is evaluated with gamma method (2%, 2 mm) at the center of GTV and the passing rate was 99.6%. The OSLD measurement shows 0.3% to 2.1% higher than expected dose at patient treatment lesion. In this study, we treated Mycosis fungoides patient with patient specific bolus using 3D printing technique. The accuracy of treatment plan was verified by pretreatment QA and in-vivo dosimetry. The QA results and 4 month follow up result shows the radiation treatment using 3D printing bolus is feasible to treat irregular patient skin.

• Journal of radiological science and technology
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• v.42 no.6
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• pp.447-454
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• 2019

In order to improve and supplement the shielding method for electron beam treatment, we designed a patient-specific shielding method using a 3D printer, and evaluated the usefulness by comparing and analyzing the distribution of electron beam doses to adjacent organs. In order to treat 5 cm sized superficial tumors around the lens, a CT Simulator was used to scan the Alderson Rando phantom and the DICOM file was converted into an STL file. The converted STL file was used to design a patient-specific shield and mold that matched the body surface contour of the treatment site. The thickness of the shield was 1 cm and 1.5 cm, and the mold was printed using a 3D printer, and the patient customized shielding block (PCSB) was fabricated with a cerrobend alloy with a thickness of 1 cm and 1.5 cm. The dosimetry was performed by attaching an EBT3 film on the surface of the Alderson Rando phantom eyelid and measuring the dose of 6, 9, and 12 MeV electron beams on the film using four shielding methods. Shielding rates were 83.89%, 87.14%, 87.39% at 6, 9, and 12 MeV without shielding, 1 cm (92.04%, 87.48%, 86.49%), 1.5 cm (91.13%, 91.88% with PSCB), 92.66%) The shielding rate was measured as 1 cm (90.7%, 92.23%, 88.08%) and 1.5 cm (88.31%, 90.66%, 91.81%) when the shielding block and the patient-specific shield were used together. PCSB fabrication improves shielding efficiency over conventional shielding methods. Therefore, PSCB may be useful for clinical application.

• Progress in Medical Physics
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• v.27 no.2
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• pp.64-71
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• 2016

We develop a manufacture procedure for the production of a patient specific customized bolus (PSCB) using a 3D printer (3DP). The dosimetric accuracy of the 3D-PSCB is evaluated for electron beam therapy. In order to cover the required planning target volume (PTV), we select the proper electron beam energy and the field size through initial dose calculation using a treatment planning system. The PSCB is delineated based on the initial dose distribution. The dose calculation is repeated after applying the PSCB. We iteratively fine-tune the PSCB shape until the plan quality is sufficient to meet the required clinical criteria. Then the contour data of the PSCB is transferred to an in-house conversion software through the DICOMRT protocol. This contour data is converted into the 3DP data format, STereoLithography data format and then printed using a 3DP. Two virtual patients, having concave and convex shapes, were generated with a virtual PTV and an organ at risk (OAR). Then, two corresponding electron treatment plans with and without a PSCB were generated to evaluate the dosimetric effect of the PSCB. The dosimetric characteristics and dose volume histograms for the PTV and OAR are compared in both plans. Film dosimetry is performed to verify the dosimetric accuracy of the 3D-PSCB. The calculated planar dose distribution is compared to that measured using film dosimetry taken from the beam central axis. We compare the percent depth dose curve and gamma analysis (the dose difference is 3%, and the distance to agreement is 3 mm) results. No significant difference in the PTV dose is observed in the plan with the PSCB compared to that without the PSCB. The maximum, minimum, and mean doses of the OAR in the plan with the PSCB were significantly reduced by 9.7%, 36.6%, and 28.3%, respectively, compared to those in the plan without the PSCB. By applying the PSCB, the OAR volumes receiving 90% and 80% of the prescribed dose were reduced from $14.40cm^3$ to $0.1cm^3$ and from $42.6cm^3$ to $3.7cm^3$, respectively, in comparison to that without using the PSCB. The gamma pass rates of the concave and convex plans were 95% and 98%, respectively. A new procedure of the fabrication of a PSCB is developed using a 3DP. We confirm the usefulness and dosimetric accuracy of the 3D-PSCB for the clinical use. Thus, rapidly advancing 3DP technology is able to ease and expand clinical implementation of the PSCB.

• Journal of Korean Academy of Nursing Administration
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• v.12 no.3
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• pp.444-453
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• 2006

Purpose: The purpose of the study was to identify critical indicators for the development of efficient patient classification system in a emergency room. Method: This study involved following five steps. Step 1. Selection of the lists direct nursing services in the ER. Step 2. Measurement of the time of direct nursing services from Aug. 31st to Nov. 30th, 2005. Step 3. Classification of the patients according to the nursing care time. Step 4. The determination the critical indicators for different patient classes. Result: Determinate indicators were as follow: 3 items in the first group (vital sign checking, IV route starting, blood sampling), 3 items in the second group (vital sign checking, fluid infusion, blood sampling), 9 items in the third group (I/O checking, $O_{2}$ inhalation, suction, fluid infusion, IV bolus, Central catheter preparation & management, blood sampling, intubation preparation & management, postmortem management), 7 items in the fourth group (EKG monitoring, BP monitoring, $O_{2}$ inhalation, fluid infusion, using the specific drugs, CPR, postmortem management). Conclusion: This study can help future studies which measure nursing services standard time or assigns value to emergency nursing services.

• Journal of Trauma and Injury
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• v.36 no.3
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• pp.165-171
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• 2023

Trauma remains a significant healthcare burden, causing over five million yearly fatalities. Notably, the liver is a frequently injured solid organ in abdominal trauma, especially in patients under 40 years. It becomes even more critical given that uncontrolled hemorrhage linked to liver trauma can have mortality rates ranging from 10% to 50%. Liver injuries, mainly resulting from blunt trauma such as motor vehicle accidents, are traditionally classified using the American Association for the Surgery of Trauma grading scale. However, recent developments have introduced the World Society of Emergency Surgery classification, which considers the patient's physiological status. The diagnostic approach often involves multiphase computed tomography (CT). Still, newer methods like split-bolus single-pass CT and contrast-enhanced ultrasound (CEUS) aim to reduce radiation exposure. Concerning management, nonoperative strategies have emerged as the gold standard, especially for hemodynamically stable patients. Incorporating angiography with embolization has also been beneficial, with success rates reported between 80% and 97%. However, it is essential to identify the specific source of bleeding for effective embolization. Given the severity of liver trauma and its potential complications, innovations in diagnostic and therapeutic approaches have been pivotal. While CT remains a primary diagnostic tool, methods like CEUS offer safer alternatives. Moreover, nonoperative management, especially when combined with angiography and embolization, has demonstrated notable success. Still, the healthcare community must remain vigilant to complications and continuously seek improvements in trauma care.

• The Korean Journal of Pain
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• v.9 no.1
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• pp.172-177
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• 1996

We performed a study of epidural patient controlled analgesia of meperidine with or without 0.08% bupivacaine for 48 hours after Cesarean section. 51 parturients were randomly assigned to one of two treatment groups : 1) epidural 0.2% meperidine group(n:24) and 2) epidural combined group with 0.2% meperidine and 0.08% bupivacaine(n:27). All parturients used patient controlled analgesia with loading dose, 2 ml/hour continuous infusion, 1 ml bolus infusion and lockout time, 8 minutes. visual analog scales after loading doses were not significantly different in either groups. The total quantity of meperidine consumption and hourly consumption were significantly lower in the combined group than meperidine group(P<0.05). The cumulative amount of meperidine consumption were also significantly lower in the combined group than meperidine group at 6, 12, 24 and 48 hours. In combined group the hourly consumption of meperidien from 3 hours to 12 hours after loading dose was significantly lower than those of meperidine group. Above 90% of parturients were satisfied in both groups. Side effects were: numbness (2), thigh weakness (1), nausea (1), headache (1) and back pain (2) in epidural meperidine group. There were no case needed specific treatment in both groups. We conclude that analgesic effects were similar in both groups, however the amount of meperidine consumption was less for meperiding group than combined group.

• The Korean Journal of Pain
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• v.9 no.1
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• pp.166-171
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• 1996

The purpose of this study is to compare the postoperative analgesic effect of morphine and meperidine, employing intravenous patient controlled analgesia after cesarean section. Among fifty nine parturients undergoing cesarean section with general anesthesia, 32 were administered morphine designated as 'morphine group', and 27 parturient administered meperidine as 'meperidine' group, during 48 hours after commencement of PCA. Doses administered, based on potency for this setting, were equivalent to 1 mg morphine or 10 mg meperidine. Loading dose was administered when parturient first complained of pain after cesarean section. This was followed with bolus dose, 1 mg for morphine group and 10 mg for meperidine group, with a lockout interval of 8 minutes between doses wherever parturient requested additional analgesia. Visual analog scale(VAS) pain scores during rest were significantly lower at only 1 and 2 hour for the meperidine group, than morphine group. Loading dose and cumulative dose at 1, 2 and 3 hours were significantly lower for meperidine group than the morphine group. There were no significant difference in total dose and hourly dose for 48 hours and cumulative dose at 6, 12, 24, and 48 hours between both groups. More than 90% of the parturients from both groups were satisfied with the analgesic effects of pain relief. Morphine group experienced side effects such as: pruritus, sedation and dizziness. Meperidine group had sedation, dizziness, nausea and local irritation. Neither group required any specific treatment for any of the above side effects. We conclude that meperidine had greater analgesic effect at early stage of post-operative period.

• Journal of Dental Anesthesia and Pain Medicine
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• v.19 no.4
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• pp.181-189
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• 2019

Local anesthetic systemic toxicity (LAST) refers to the complication affecting the central nervous system (CNS) and cardiovascular system (CVS) due to the overdose of local anesthesia. Its reported prevalence is 0.27/1000, and the representative symptoms range from dizziness to unconsciousness in the CNS and from arrhythmias to cardiac arrest in the CVS. Predisposing factors of LAST include extremes of age, pregnancy, renal disease, cardiac disease, hepatic dysfunction, and drug-associated factors. To prevent the LAST, it is necessary to recognize the risk factors for each patient, choose a safe drug and dose of local anesthesia, use vasoconstrictor, confirm aspiration and use incremental injection techniques. According to the treatment guidelines for LAST, immediate application of lipid emulsion plays an important role. Although lipid emulsion is commonly used for parenteral nutrition, it has recently been widely used as a non-specific antidote for various types of drug toxicity, such as LAST treatment. According to the recently published guidelines, 20% lipid emulsion is to be intravenously injected at 1.5 mL/kg. After bolus injection, 15 mL/kg/h of lipid emulsion is to be continuously injected for LAST. However, caution must be observed for >1000 mL of injection, which is the maximum dose. We reviewed the incidence, mechanism, prevention, and treatment guidelines, and a serious complication of LAST occurring due to dental anesthesia. Furthermore, we introduced lipid emulsion that has recently been in the spotlight as the therapeutic strategy for LAST.