• The Journal of Korean Society for Radiation Therapy
• /
• v.22 no.2
• /
• pp.105-111
• /
• 2010

Purpose: There are various beam parameter in intensity modulated radiation therapy (IMRT). The aim of this study is to investigate how various dose rate affect the parotid in treatment plan of IMRT. Materials and Methods: The study was performed on 10 nasopharyngeal carcinoma patients who have undergone IMRT. CT images were scanned 3 mm of thickness in the same condition and the treatment plan was performed by Eclipse (Ver.7.1, Varian, Palo Alto, USA). The parameters for planning used 6 MV energy and 8 beams under the same dose volume constraint. The variation of dose rates were used 300, 400, 500 MU/min. The mean dose of both parotid was accessed from the calculated planning among the 10 patients. The mean dose of parotid was verificated by 2D diode array (Mapcheck from Sun Nuclear Corporation, Melbourne, Florida). Also, Total monitor unit (MU) and beam-on time was analysed. Results: According to the dose rate, the mean dose of parotid was increased by 0.8%, 2.0% each, when dose rate was changed from 300 MU/min to 400, 500 MU/min, moreover Total MU was increased by 5.4% and 10.6% each. There was also a dose upward trend in the dose measurement of parotid by 2D diode array. However, beam - on time difference of 1~2 minutes was no signigicant in the dose rate increases. Conclusion: From this study, when the dose rates increase, there was a signigicant increase of Total MU and the parotid dose accordingly, however the shortened treatment time was not significant. Hence, it is considered that there is a significant decrease of late side effect in parotid radiation therapy, if the precise dose rate in IMRT is used.

• Radiation Oncology Journal
• /
• v.24 no.4
• /
• pp.285-293
• /
• 2006

$\underline{Purpose}$: This study was to search the optimal slice thickness of computed tomography (CT) in an intensity modulated radiation therapy plan through changing the slice thickness and comparing the change of the calculated absorbed dose with measured absorbed dose. $\underline{Materials\;and\;Methods}$: An intensity modulated radiation therapy plan for a head and neck cancer patient was done, first of all. Then CT with various ranges of slice thickness ($0.125{\sim}1.0\;cm$) for a head and neck anthropomorphic phantom was done and the images were reconstructed. The plan parameters obtained from the plan of the head and neck cancer patient was applied into the reconstructed images of the phantom and then absorbed doses were calculated. Films were inserted into the phantom, and irradiated with 6 MV X-ray with the same beam data obtained from the head and neck cancer patient. Films were then scanned and isodoses were measured with the use of film measurement software and were compared with the calculated isodeses. $\underline{Results}$: As the slice thickness of CT decreased, the volume of the phantom and the maximum absorbed dose increased. As the slice thickness of CT changed from 0.125 to 1.0 cm, the maximum absorbed dose changed ${\sim}5%$. The difference between the measured and calculated volume of the phantom was small ($3.7{\sim}3.8%$) when the slice thickness of CT was 0.25 cm or less. The difference between the measured and calculated dose was small ($0.35{\sim}1.40%$) when the slice thickness of CT was 0.25 cm or less. $\underline{Conclusion}$: Because the difference between the measured and calculated dose in a head and neck phantom was small and the difference between the measured and calculated volume was small when the slice thickness of CT was 0.25 cm or less, we suggest that the slice thickness of CT should be 0.25 cm or less for an optimal intensity modulated radiation therapy plan.

• Korean Journal of Head & Neck Oncology
• /
• v.10 no.2
• /
• pp.178-184
• /
• 1994

Laryngeal cancer is one of the most frequent cancers in the head and neck area. Clinical analysis was performed on 30 cases of treated $T_1$ glottic cancer patients. Early glottic cancer occured most frequently in male in their sixties and all were well or moderately well differentiated squamous cell carcinoma. Overall five year survival rate was 81.5% and there was no significant difference between stages or the differentiation of the diseases. Recurrence at the primary site, especially anterior commissure, was common, thus careful pre- and postoperative follow up evaluation is recommended.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1993.05a
• /
• pp.84-84
• /
• 1993

Overexpression of the mutant p53, derived from mutation of the p53 gene which is located on the short arm of chromosome 17 and plays a role in suppression of the tumor, was reported in some human malignancy such as breast or colon carcinoma and suggested to be a prognostic factor. The authors investigated expression of p53 protein by immunohistochemical staining using anti-p53 monoclonal antibody in the paraffin embedded blocks of the 23 patients who were diagnosed at Seoul National University Hospital as adenoid cystic carcinoma of the head and neck between 1982 and 1991, and could be followed-up. 7 cases(34%) out of the 23 cases showed p53 expression, and there was no significant association between p53 positivity and local recurrence(p=0.31) or distant metastasis(p=0.16)

• The Journal of Korean Society for Radiation Therapy
• /
• v.30 no.1_2
• /
• pp.97-105
• /
• 2018

Purpose : Proton Therapy using Bragg-peak, because it has distinct characteristics in providing maximum dosage for tumor and minimal dosage for normal tissue, a medical imaging system that can quantify changes in patient position or treatment area is of paramount importance to the treatment of protons. The purpose of this research is to evaluate the usefulness of the algorithm by comparing the image matching through the set-up and in-house code through the existing dips program by producing a Matlab-based in-house registration code to determine the error value between dips and DRR to evaluate the accuracy of the existing treatment. Materials and Methods : Thirteen patients with brain tumors and head and neck cancer who received proton therapy were included in this study and used the DIPS Program System (Version 2.4.3, IBA, Belgium) for image comparison and the Eclipse Proton Planning System (Version 13.7, Varian, USA) for patient treatment planning. For Validation of the Registration method, a test image was artificially rotated and moved to match the existing image, and the initial set up image of DIPS program of existing set up process was image-matched with plan DRR, and the error value was obtained, and the usefulness of the algorithm was evaluated. Results : When the test image was moved 0.5, 1, and 10 cm in the left and right directions, the average error was 0.018 cm. When the test image was rotated counterclockwise by 1 and $10^{\circ}$, the error was $0.0011^{\circ}$. When the initial images of four patients were imaged, the mean error was 0.056, 0.044, and 0.053 cm in the order of x, y, and z, and 0.190 and $0.206^{\circ}$ in the order of rotation and pitch. When the final images of 13 patients were imaged, the mean differences were 0.062, 0.085, and 0.074 cm in the order of x, y, and z, and 0.120 cm as the vector value. Rotation and pitch were 0.171 and $0.174^{\circ}$, respectively. Conclusion : The Matlab-based In-house Registration code produced through this study showed accurate Image matching based on Intensity as well as the simple image as well as anatomical structure. Also, the Set-up error through the DIPS program of the existing treatment method showed a very slight difference, confirming the accuracy of the proton therapy. Future development of additional programs and future Intensity-based Matlab In-house code research will be necessary for future clinical applications.

• Progress in Medical Physics
• /
• v.19 no.2
• /
• pp.89-94
• /
• 2008

TomoTherapy has a merit to treat cancer with Intensity modulated radiation and combines precise 3-D imaging from computerized tomography (CT scanning) with highly targeted radiation beams and rotating beamlets. In this paper, we comparing the dose distribution between TomoTherapy and linear accelerator based intensity modulated radiotherapy (IMRT) for 10 Head & Neck patients using TomoTherapy which is newly installed and operated at National Cancer Center since Sept. 2006. Furthermore, we estimate how the homogeneity and Normal Tissue Complication Probability (NTCP) are changed by motion of target. Inverse planning was carried out using CadPlan planning system (CadPlan R.6.4.7, Varian Medical System Inc. 3100 Hansen Way, Palo Alto, CA 94304-1129, USA). For each patient, an inverse IMRT plan was also made using TomoTherapy Hi-Art System (Hi-Art2_2_4 2.2.4.15, TomoTherapy Incorporated, 1240 Deming Way, Madson, WI 53717-1954, USA) and using the same targets and optimization goals. All TomoTherapy plans compared favorably with the IMRT plans regarding sparing of the organs at risk and keeping an equivalent target dose homogeneity. Our results suggest that TomoTherapy is able to reduce the normal tissue complication probability (NTCP) further, keeping a similar target dose homogeneity.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.33 no.3
• /
• pp.172-178
• /
• 2022

Background and Objectives Injection laryngoplasty is a common method for treatment of unilateral vocal fold paralysis. Unilateral vocal fold paralysis has various causes, including idiopathic, infection, stroke, neurologic condition, surgery and nerve invasion by cancer. To the knowledge of the authors, there was no study on the relationship between the causes of vocal cord paralysis and the outcome of injection laryngoplasty. Therefore, we tried to investigate the difference in the outcomes of injection laryngoplasty between vocal cord paralysis after surgery group and nerve invasion by cancer group. Materials and Method A retrospective analysis was performed for 24 patients who underwent vocal cord injection due to unilateral vocal cord paralysis caused by surgery or nerve invasion by cancer. The objective quality of the voice was assessed by acoustic voice analysis with the Multi-Dimensional Voice Program. Results Both group showed an improvement of fundamental frequemcy (F0), jitter percent, shimmer (percent), and noise to hearmonic ratio (NHR) after injection laryngoplasty. The vocal cord paralysis due to nerve invasion group showed more improvement in both the mean and median value of F0, shimmer percent and NHR than the vocal cord paralysis due to surgery group, but there was not statistically significant. Conclusion Our study did not show a statistically significant difference in outcome between vocal cord paralysis due to cancer invasion group and surgery group, but statistically tendency was suggested. The vocal cord paralysis due to nerve invasion group showed more improvement in both the mean and median value of acoustic voice analysis than surgery group.

• Radiation Oncology Journal
• /
• v.6 no.2
• /
• pp.253-258
• /
• 1988

To evaluate radiation effect on the hematopoietic system, we analyzed 44 patients who were treated with conventionally fractionated radiation therapy (RT) at Chonbuk National University Hospital. According to the treatment sites, we classified them into three groups: group I as head and neck, group II as thorax, and group III as pelvis. White blood cell, lymphocyte, platelet and hemoglobin were checked before and during RT The results were as follows; 1. White blood cell (WBC) and lymphocyte count were declined from the first week of RT to the third week, and then slightly recovered after the third or fourth week. There was prominent decrease in lymphocyte counts than WBC. 2. Platelet counts were declined until the second week of the RT, showed slight recovery at fourth week in all groups. Hemoglobin values were slightly decreased in the first week and then recovered the level of pretreatment value, gradually. 3. Lymphocyte count were declined significantly on group III(p<0.05), WBC and platelet counts were decreased on group II but statistically not significant.

• Korean Journal of Head & Neck Oncology
• /
• v.30 no.2
• /
• pp.74-78
• /
• 2014

갑상선 암 진단과 치료기술이 발전하면서 최근 그 수술 건 수가 급격하게 증가하고 있다. 하지만이와 관련된 합병증과 부작용을 면밀하게 평가해야 할 필요 역시 점차 늘어나고 있다. 갑상선 암 수술 후 발생할 수 있는 드문 합병증의 하나로 횡격막 신경마비(phrenic nerve paralysis)가 있다. 이러한 횡격막신경마비는 대부분 증상이 경미하고 쉽게 호전되어 임상적으로 크게 중요하게 다루어지지 않았다. 하지만, 갑상선 수술 후 갑작스런 호흡곤란이 발생한다면 횡격막 신경마비에 의한 횡격막 마비(diaphragmatic paralysis)와 관련되었을 가능성을 놓치지 말아야 한다. 저자들은 최근 갑상선암 수술 후 발생한 호흡곤란으로 2년 동안 심각한 호흡곤란을 호소하던 73세 여자환자에서 투시촬영(fluoroscopy) 상 편측으로 상승되고 운동성이 저하된 횡격막을 확인하여 일측성 횡격막신경마비(Unilateral phrenic nerve paralysis)를 확진 하였다. 갑상선수술 후 발생하는 일측 횡경막 신경마비는 임상에서 드물게 관찰되는 수술 합병증이기에 환자는 상당기간 이에 대한 감별이 제대로 이루어지지 않았다. 우리는 횡격막 마비의 조기 진단과 적극적인 치료를 통하여 심한 호흡곤란을 호소하는 환자의 증상 및 병의 경과를 호전 시킬 수 있었다.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.29 no.1
• /
• pp.9-13
• /
• 2018

Postoperative airway aspiration is not uncommon in patients with head and neck cancer. Airway aspiration has serious consequences, such as swallowing disorders, nutrition-related health problem, or reducing the quality of life due to maintenance of tracheal or nasogastric tubes. The postoperative oropharyngeal defect due to the surgery may interfere with normal swallowing reflex, or the laryngeal dysfunction caused by radiation therapy may cause severe airway aspiration, which may lead to complications such as dyspnea and pneumonia. Complete removal of the disease is also important in the treatment of head and neck cancer, but it is necessary to select a method to avoid and predict the occurrence of airway aspiration according to the treatment method. The most important factor to prevent airway aspiration after surgery is to preserve the proper volume of the oropharynx and to preserve at least one of the cricoarytenoid joint function. It is also the most effective way to reduce additional complications by seeking appropriate surgical treatment according to airway aspiration status. The purpose of this study is to review the operative methods that can induce airway aspiration and consider the prevention and treatment strategy through review of the literature.