• The Journal of Korean Society for Radiation Therapy
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• v.20 no.1
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• pp.11-15
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• 2008

Purpose: The goal of radiation treatment is to deliver a prescribed radiation dose to the target volume accurately while minimizing dose to normal tissues. In this paper, we comparing the dose distribution between three dimensional conformal radiation radiotherapy (3D-CRT) and helical tomotherapy (TOMO) plan for partial breast cancer. Materials and Methods: Twenty patients were included in the study, and plans for two techniques were developed for each patient (left breast:10 patients, right breast:10 patients). For each patient 3D-CRT planning was using pinnacle planning system, inverse plan was made using Tomotherapy Hi-Art system and using the same targets and optimization goals. We comparing the Homogeneity index (HI), Conformity index (CI) and sparing of the organs at risk for dose-volume histogram. Results: Whereas the HI, CI of TOMO was significantly better than the other, 3D-CRT was observed to have significantly poorer HI, CI. The percentage ipsilateral non-PTV breast volume that was delivered 50% of the prescribed dose was 3D-CRT (mean: 40.4%), TOMO (mean: 18.3%). The average ipsilateral lung volume percentage receiving 20% of the PD was 3D-CRT (mean: 4.8%), TOMO (mean: 14.2), concerning the average heart volume receiving 20% and 10% of the PD during treatment of left breast cancer 3D-CRT (mean: 1.6%, 3.0%), TOMO (mean: 9.7%, 26.3%) Conclusion: In summary, 3D-CRT and TOMO techniques were found to have acceptable PTV coverage in our study. However, in TOMO, high conformity to the PTV and effective breast tissue sparing was achieved at the expense of considerable dose exposure to the lung and heart.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.3
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• pp.985-989
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• 2012

Objective: To make sure the feasibility with $^{18F}FDG$ PET/CT to guided dynamic intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma patients, by dosimetric verification before treatment. Methods: Chose 11 patients in III~IVA nasopharyngeal carcinoma treated with functional image-guided IMRT and absolute and relative dosimetric verification by Varian 23EX LA, ionization chamber, 2DICA of I'mRT Matrixx and IBA detachable phantom. Drawing outline and making treatment plan were by different imaging techniques (CT and $^{18F}FDG$ PET/CT). The dose distributions of the various regional were realized by SMART. Results: The absolute mean errors of interest area were $2.39%{\pm}0.66$ using 0.6cc ice chamber. Results using DTA method, the average relative dose measurements within our protocol (3%, 3 mm) were 87.64% at 300 MU/min in all filed. Conclusions: Dosimetric verification before IMRT is obligatory and necessary. Ionization chamber and 2DICA of I'mRT Matrixx was the effective dosimetric verification tool for primary focal hyper metabolism in functional image-guided dynamic IMRT for nasopharyngeal carcinoma. Our preliminary evidence indicates that functional image-guided dynamic IMRT is feasible.

• Archives of Craniofacial Surgery
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• v.17 no.2
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• pp.45-50
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• 2016

Extensive surgical resection of the aerodigestive track can result in a large and complex defect of the oropharynx, which represents a significant reconstructive challenge for the plastic surgery. Development of microsurgical techniques has allowed for free flap reconstruction of oropharyngeal defects, with superior outcomes as well as decreases in postoperative complications. The reconstructive goals for oral and oropharyngeal defects are to restore the anatomy, to maintain continuity of the intraoral surface and oropharynx, to protect vital structures such as carotid arteries, to cover exposed portions of internal organs in preparation for adjuvant radiation, and to preserve complex functions of the oral cavity and oropharynx. Oral and oropharyngeal cancers should be treated with consideration of functional recovery. Multidisciplinary treatment strategies are necessary for maximizing disease control and preserving the natural form and function of the oropharynx.

• The Korean Journal of Gastroenterology
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• v.72 no.6
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• pp.277-280
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• 2018

Although small bowel the mainly occupies the most part of the gastrointestinal tract, small intestine tumors are rare, insidious in clinical presentation, and frequently represent a diagnostic and management challenge. Small bowel tumors are generally classified as epithelial, mesenchymal, lymphoproliferative, or metastatic. Familial adenomatous polyposis and Peutz-Jeghers syndrome are the most common inherited intestinal polyposis syndromes. Until the advent of capsule endoscopy (CE) and device-assisted enteroscopy (DAE) coupled with the advances in radiology, physicians had limited diagnostic examination for small bowel examination. CE and new radiologic imaging techniques have made it easier to detect small bowel tumors. DAE allows more diagnosis and deeper reach in small intestine. CT enteroclysis/CT enterography (CTE) provides information about adjacent organs as well as pictures of the intestinal lumen side. Compared to CTE, Magnetic resonance enteroclysis/enterography provides the advantage of soft tissue contrast and multiplane imaging without radiation exposure. Treatment and prognosis are tailored to each histological subtype of tumors.

• Journal of radiological science and technology
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• v.31 no.4
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• pp.401-406
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• 2008

The aim of this study is to evaluate contra-lateral breast (CLB) surface dose in Field-in-Field (FIF) technique for breast conserving surgery patients. For evaluation of surface dose in FIF technique, we have compared with other techniques, which were open fields (Open), metal wedge (MW), and enhanced dynamic wedge (EDW) techniques under same geometrical condition and prescribed dose. The three dimensional treatment planning system was used for dose optimization. For the verification of dose calculation, measurements using MOSFET detectors with Anderson Rando phantom were performed. The measured points for four different techniques were at the depth of 0cm (epidermis) and 0.5cm bolus (dermis), and spacing toward 2cm, 4cm, 6cm, 8cm, 10cm apart from the edge of tangential medial beam. The dose calculations were done in 0.25cm grid resolution by modified Batho method for inhomogeneity correction. In the planning results, the surface doses were differentiated in the range of $19.6{\sim}36.9%$, $33.2{\sim}138.2%$ for MW, $1.0{\sim}7.9%$, $1.6{\sim}37.4%$ for EDW, and for FIF at the depth of epidermis and dermis as compared to Open respectively. In the measurements, the surface doses were differentiated in the range of $11.1{\sim}71%$, $22.9{\sim}161%$ for MW, $4.1{\sim}15.5%$, $8.2{\sim}37.9%$ for EDW, and 4.9% for FIF at the depth of epidermis and dermis as compared to Open respectively. The surface doses were considered as underestimating in the planning calculation as compared to the measurement with MOSFET detectors. Was concluded as the lowest one among the techniques, even if it was compared with Open method. Our conclusion could be stated that the FIF technique could make the optimum dose distribution in Breast target, while effectively reduce the probability of secondary carcinogenesis due to undesirable scattered radiation to contra-lateral breast.

• Progress in Medical Physics
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• v.25 no.2
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• pp.65-71
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• 2014

A Varian Portal Dosimetry system was compared to an isocentrically mounted MapCHECK 2 diode array for volumetric modulated arc therapy (VMAT) QA. A Varian TrueBeam STx with an aS-1000 digital imaging panel was used to acquire VMAT QA images for 13 plans using four photon energies (6, 8, 10 and 15 MV). The EPID-based QA images were compared to the Portal Dose Image Prediction calculated in the Varian Eclipse treatment planning system (TPS). An isocentrically mounted Sun Nuclear MapCHECK 2 diode array with 5 cm water-equivalent buildup was also used for the VMAT QAs and the measurements were compared to a composite dose plane from the Eclipse TPS. A ${\gamma}$ test was implemented in the Sun Nuclear Patient software with 10% threshold and absolute comparison at 1%/1 mm (dose difference/distance-to-agreement), 2%/2 mm, and 3%/3 mm criteria for both QA methods. The two-tailed paired Student's t-test was employed to analyze the statistical significance at 95% confidence level. The average ${\gamma}$ passing rates were greater than 95% at 3%/3 mm using both methods for all four energies. The differences in the average passing rates between the two methods were within 1.7% and 1.6% of each other when analyzed at 2%/2 mm and 3%/3 mm, respectively. The EPID passing rates were somewhat better than the MapCHECK 2 when analyzed at 1%/1 mm; the difference was lower for 8 MV and 10 MV. However, the differences were not statistically significant for all criteria and energies (p-values >0.05). The EPID-based QA showed large off-axis over-response and dependence of ${\gamma}$ passing rate on energy, while the MapCHECK 2 was susceptible to the MLC tongue-and-groove effect. The two fluence-based QA techniques can be an alternative tool of VMAT QA to each other, if the limitations of each QA method (mechanical sag, detector response, and detector alignment) are carefully considered.

• Radiation Oncology Journal
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• v.37 no.3
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• pp.149-155
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• 2019

In metastatic non-small cell lung cancer (NSCLC), the role of radiotherapy (RT) has been limited to palliation to alleviate the symptoms. However, with the development of advanced RT techniques, recent advances in immuno-oncology therapy targeting programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) and targeted agents for epidermal growth factor receptor (EGFR) mutation or anaplastic lymphoma kinase (ALK) translocation allowed new roles of RT in these patients. Within this metastatic population, there is a subset of patients with a limited number of sites of metastatic disease, termed as oligometastasis that can achieve long-term survival from aggressive local management. There is no consensus on the definition of oligometastasis; however, most clinical trials define oligometastasis as having 3 to 5 metastatic lesions. Recent phase II randomized clinical trials have shown that ablative RT, including stereotactic ablative body radiotherapy (SABR) and hypofractionated RT, to primary and metastatic sites improved progression-free survival (PFS) and overall survival (OS) in patients with oligometastatic NSCLC. The PEMBRO-RT study, a randomized phase II study comparing SABR prior to pembrolizumab therapy and pembrolizumab therapy alone, revealed that the addition of SABR improved the overall response, PFS, and OS in patients with advanced NSCLC. The efficacy of RT in oligometastatic lung cancer has only been studied in phase II studies; therefore, large-scale phase III studies are needed to confirm the benefit of local ablative RT in patients with oligometastatic NSCLC. Local intensified RT to primary and metastatic lesions is expected to become an important treatment paradigm in the near future in patients with metastatic lung cancer.

• Journal of radiological science and technology
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• v.46 no.5
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• pp.379-394
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• 2023

Targeted Alpha Therapy (TAT) is a new method of cancer treatment that protects normal tissues while selectively killing tumor cells using high cytotoxicity and short range of alpha particles, and target alpha therapy is a highly specific and effective cancer treatment strategy, and its potential has been proven through many clinical and experimental studies. This treatment method accurately delivers alpha particles by selecting specific molecules present in cancer tissue, which has an effective destruction and tumor suppression effect on cancer cells, and one of the main advantages of target alpha treatment is the physical properties of alpha particles. Alpha particles have a very high energy and short effective distance, interacting with target molecules in cancer tissues and having a fatal effect on cancer cells, which is known to cause DNA damage and cell death in cancer cells. TAT has shown positive results in preclinical and clinical studies for various types of cancers, especially those that resist or are unresponsive to existing treatments, but there are several challenges and limitations to overcome for successful clinical transition and application. These include the provision and production of suitable alpha radioisotopes, optimization of target vectors and delivery formulations, understanding and regulation of radiological effects, accurate dosage calculation and toxicity assessment. Future research should focus on developing new or improved isotopes, target vectors, transfer formulations, radiobiological models, combination strategies, imaging techniques, etc. for TAT. In addition, TAT has the potential to improve the quality of life and survival of cancer patients due to the possibility of a new treatment for overcoming cancer, and to this end, prospective research on more carcinomas and more diverse patient groups is needed.

• Journal of radiological science and technology
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• v.39 no.2
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• pp.177-184
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• 2016

Recently linear accelerator of radiation therapy intensity modulated radiation therapy, stereotactic radiation therapy are widely used. Such radiation treatment techniques are generally difficult to exclude the small field by using the inverse treatment plan. It is necessary to dose an accurate measurement of characteristics of the small field. Thus, using different detectors to measure the volume of the effective percentage depth dose, beam profile, and the output factor of the small field was to evaluate the dose characteristics of each detector. Experimental results for the X-ray beam 6 MV energy beam quality($PDD_{20}/PDD_{10}$) is $10{\times}10cm^2$ Diode detector is as high as 2.4% compared to Pinpoint detector. All field size to lesser effective volume of Diode detector shows that it is far better than other detectors by more than 50% of small penumbra, therefore spatial resolution far excellent. In field size $2{\times}2cm^2$ Semiflex detector was measured about 2% less than the other detector. Field size $1{\times}1cm^2$ is that there is no judgment about the validity show the difference between 20%. Field size $1{\times}1cm^2$ from the measured values of the Diode detector and Pinpoint detector showed a 13% difference. Less than field size $3{\times}3cm^2$ the feed to the difference between the output factor of the effective volume of the detector to be used for the effective volume available to the detector.

• Progress in Medical Physics
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• v.18 no.4
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• pp.202-208
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• 2007

Various techniques were evaluated to determine the best method for reducing small bowel involvement in pelvic irradiation. Fourteen patients receiving radiation in pelvic area were enrolled for this study. Five sets of small bowel images were obtained. Patients were positioned on a simulation couch with full bladder in prone and supine positions and 2 sets of images were taken. Then they were asked to empty their bladder and 2 sets of images were taken in prone and supine positions. A belly board device (BBD) was placed and one set of images was obtained. Using a software, the area of small bowel inside treatment field was contoured, measured, and analyzed. In both full and empty bladder cases, small bowel area reduction was observed in prone position as compared to supine position. Especially statistically significant reduction is noted in lateral film. An average decreases of 13% in PA and 26% in lateral direction were noted with bladder distention as compared to empty bladder. With the use of BBD for empty bladder, a significant reduction of $62.8{\pm}27.1%$ and $63.1{\pm}32.9%$ in PA and lateral directions were observed as compared to without BBD in prone position, respectively. In conclusion, the best sparing of small bowel concerning the area included in the treatment fields was achieved with BBD in prone position with empty bladder. However, further reduction is expected if the bladder was filled fully because the analysed data with empty vs full bladder study shows increased sparing of small bowel with distended bladder.