• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.29 no.2
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• pp.103-106
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• 2018

Tracheobronchopathia osteochondroplastica (TO) is a rare idiopathic tracheobronchial abnormality characterized by diffuse cartilaginous and osseous nodules protruding into the airway lumen of the trachea and bronchus. TO is easy to misdiagnose because of nonspecific symptoms and chest CT scan with pathologic biopsy is necessary for definitive diagnosis. We report two cases of patient with TO who underwent laryngomicroscopic biopsy and tracheostomy with literature review.

• Korean Journal of Head & Neck Oncology
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• v.14 no.2
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• pp.169-174
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• 1998

Background: To avoid the major mobidity associated with bilateral radical neck dissection, modified radical neck dissection has become established as an effective adjunctive procedure in the management of head and neck cancer. But several studies reported early postoperative internal jugular vein(IJV) occlusion in patients who underwent modified radical neck dissection. Objectives: To determine internal jugular vein patency following modified radical neck dessection performed in various head and neck cancer and to identify factors associated with venous occlusion. Materials and Methods: From Aug. 1996 to Oct. 1997, twenty three patients underwent either unilateral or bilateral modified radical neck dissection; 19 males and 4 females, ranging in age from 28 to 75 were retrospectively examined. All patients had a preoperative doppler imaging or CT or both for their initial evaluation. A follow-up examination was obtained(after a minimum postoperative period of 2 months and a maximum one of 4 months). Results: Thirty-four IJVs were examined. All but six IJVs examined were found patent postoperatively. The preservation rate of patency of the IJV in modified radical neck dissection was found to be high(28 of 34 IJVs or 82%). Conclusion: The preservation rate of patency of the IJV in modified radical neck dissection was found to be high. These results favor the use of modified radical neck dissection for IJV preservation, particularly in bilateral neck dissection. A retrospective chart review revealed that trauma of the vessel and extrinsic compression of the vein by the musculocutaneous flap or recurrent carcinoma in the neck may be the cause of the vein occlusion.

• 대한두경부종양학회:학술대회논문집
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• 1997.11a
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• pp.293.2-293.2
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• 1997

• The Korean Journal of Nuclear Medicine
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• v.33 no.6
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• pp.466-474
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• 1999

Purpose: The purpose of this study was to evaluate the diagnostic accuracy of [$^{18}F$]FDG PET in the diagnosis of recurrent head and neck cancer after the completion of surgery and radiotherapy in patients with head and neck cancers. Materials and Methods: In fifty-nine patients with head and neck cancers whole body [$^{18}F$]FDG PET studies were performed. According to the different therapeutic modalities, patients were divided into four groups (Group I; pre-treatment, Group II: surgery, Group III; radiotherapy, Group IV; both surgery and radiotherapy). [$^{18}F$]FDG PET images were compared with clinical, CT and histopathologic findings. Results: for detection of metastatic lymph nodes in 14 patients of pre-treatment group (group I), the sensitivity and specificity of PET were 100% (10/10) and 75% (3/4), and those of CT were 80% (8/10) and 100% (4/4). For detection of recurrence in 45 patients of post-treatment group, overall sensitivity and specificity of PET were 96.2% (25/26) and 78.9% (15/19) [(100% and 75% in group II, 80% and 10% in group III, and 100% and 100% in group IV)] without significant difference from pre-treatment group (P>0.1). In detecting recurrence, the sensitivity and specificity of [$^{18}F$]FDG PET were 90.9% (10/11) and 20% (1/5) in 16 patients who underwent [$^{18}F$]FDG PET within 2 months after the completion of treatment. The specificity of these patients was significantly lower than that of 29 patients (100% of sensitivity and specificity) who underwent [$^{18}F$]FDG PET 2 months after treatment (p<0.05). Conclusion: [$^{18}F$]FDG PET is an accurate diagnostic modality for the detection of recurrence in head and neck cancer. Post-therapy [$^{18}F$]FDG PET should be obtained at least 2 months after the completion of surgery or radiotherapy.

• Korean Journal of Head & Neck Oncology
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• v.16 no.2
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• pp.216-219
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• 2000

Small cell carcinoma usually occurs in lung, but extrapulmonary small cell carcinomas can occur in any sites of body. Most sites of extrapulmonary small cell carcinoma reported were esophagus. And small cell carcinomas occurred in head and neck area were reported rarely. Extrapulmonary small cell carcinoma could be diagnosed when there is no evidence of primary lung lesion on chest X-ray, CT scan of chest and bronchoscopy. The authors experienced a case of small cell carcinoma of left submandibular lymph node in 64-year-old male patient. Biopsy specimen showed poorly differentiated carcinoma but immunohistochemical study showed small cell carcinoma. The chest X-ray and CT scan of chest showed no evidence of primary lung lesion. The patient received chemotherapy(etoposide plus cisplatin) and concurrent chemoradiotherapy using weekly taxol which resulted in good clinical remission. He is still alive 8 months after diagnosis without evidence of lung disease. We report our case with a brief review of literatures.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.107-114
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• 2014

Purpose : The purpose of this study is evaluation for the applicability of O-MAR(Metal artifact Reduction for Orthopedic Implants)(ver. 3.6.0, Philips, Netherlands) in head & neck radiation treatment planning CT with metal artifact created by dental implant. Materials and Methods : All of the in this study's CT images were scanned by Brilliance Big Bore CT(Philips, Netherlands) at 120kVp, 2mm sliced and Metal artifact reduced by O-MAR. To compare the original and reconstructed CT images worked on RTPS(Eclipse ver 10.0.42, Varian, USA). In order to test the basic performance of the O-MAR, The phantom was made to create metal artifact by dental implant and other phantoms used for without artifact images. To measure a difference of HU in with artifact images and without artifact images, homogeneous phantom and inhomogeneous phantoms were used with cerrobend rods. Each of images were compared a difference of HU in ROIs. And also, 1 case of patient's original CT image applied O-MAR and density corrected CT were evaluated for dose distributions with SNC Patient(Sun Nuclear Co., USA). Results : In cases of head&neck phantom, the difference of dose distibution is appeared 99.8% gamma passing rate(criteria 2 mm / 2%) between original and CT images applied O-MAR. And 98.5% appeared in patient case, among original CT, O-MAR and density corrected CT. The difference of total dose distribution is less than 2% that appeared both phantom and patient case study. Though the dose deviations are little, there are still matters to discuss that the dose deviations are concentrated so locally. In this study, The quality of all images applied O-MAR was improved. Unexpectedly, Increase of max. HU was founded in air cavity of the O-MAR images compare to cavity of the original images and wrong corrections were appeared, too. Conclusion : The result of study assuming restrained case of O-MAR adapted to near skin and low density area, it appeared image distortion and artifact correction simultaneously. In O-MAR CT, air cavity area even turned tissue HU by wrong correction was founded, too. Consequentially, It seems O-MAR algorithm is not perfect to distinguish air cavity and photon starvation artifact. Nevertheless, the differences of HU and dose distribution are not a huge that is not suitable for clinical use. And there are more advantages in clinic for improved quality of CT images and DRRs, precision of contouring OARs or tumors and correcting artifact area. So original and O-MAR CT must be used together in clinic for more accurate treatment plan.

• Imaging Science in Dentistry
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• v.30 no.1
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• pp.87-91
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• 2000

Lymphangiomas are uncommon benign congenital tumors. Most occur in the head and neck and most lesions present by the age of 2 years. We present our experience with four patients who have lymphangiomas of the head and neck with tongue involvement. First case is a 7-year-old male who has the cystic lymphangioma of left submandibular area. Second a 22-year-old female has a lesion involving the border of right tongue. Third case is the lymphangioma which occurs in the right upper lip of a 6-year old male. The last patient is a 28-year old male who fell down and whose right face was swollen up. He had undergone an operation and been treated with steroid before. The characteristic appearances of imaging methods were described and all lesions best depicted on T2-weighted images. Our experience indicates that MRI is useful in the diagnosis and treatment planning of lymphangioma.

• Korean Journal of Bronchoesophagology
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• v.14 no.1
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• pp.46-49
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• 2008

Neurofibroma is a neurogenic tumor arising from schwann cells or peripheral tissues of nerve sheaths. Neurofibroma rarely occurs as a solitary lesion but mostly occurs as part of neurofibromatosis and reports of neurofibromas developed in the nasal cavity or paranasal sinus are very rare. We report on a case of neurofibroma of the nasal cavity treated by endoscopic surgery. Preoperative computed tomography(CT), and punch biopsy suggested that the tumor was benign neurogenic tumor cofined to right nasal cavity. The tumor was removed with endoscopic surgery completely, and confirmed as neurofibroma by histological and immunohistochemical examination. We discuss the clinical and pathological characters of neurofibroma arising in the nasal septum.

• Progress in Medical Physics
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• v.15 no.2
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• pp.112-119
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• 2004

We tried to build human models based on medical images of live Korean, instead of using standard data of human body structures. Characteristics of mechanical structures of human bodies were obtained from medical images such as CT and MR images. For each constitutional part of mechanical structures CT images were analyzed in terms of gray levels and MR images were analyzed in terms of pulse sequence. Characteristic features of various mechanical structures were extracted from the analyses. Based on the characteristics of each structuring element we peformed image segmentation on CT and MR images. We delineated bones, muscles, ligaments and tendons from CT and MR images using image segmentation or manual drawing. For the image segmentation we compared the edge detection method, region growing method and intensity threshold method and applied an optimal compound of these methods for the best segmentation results. Segmented mechanical structures of the head/neck part were three dimensionally reconstructed.

• Progress in Medical Physics
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• v.32 no.3
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• pp.59-69
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• 2021

Purpose: The relationship between computed tomography (CT) number and electron density (ED) has been investigated in previous studies. However, the role of these measures for guiding cancer treatment remains unclear. Methods: The CT number was plotted against ED for different imaging protocols. The CT number was imported into ED tables for the Pinnacle treatment planning system (TPS) and was used to determine the effect on dose calculations. Conversion tables for radiation dose calculations were generated and subsequently monitored using a dosimeter to determine the effect of different CT scanning protocols and treatment sites. These tables were used to retrospectively recalculate the radiation therapy plans for 41 patients after an incorrect scanning protocol was inadvertently used. The gamma index was further used to assess the dose distribution, percentage dose difference (DD), and distance-to-agreement (DTA). Results: For densities <1.1 g/cm³, the standard deviation of the CT number was ±0.6% and the greatest variation was noted for brain protocol conditions. For densities >1.1 g/cm³, the standard deviation of the CT number was ±21.2% and the greatest variation occurred for the tube voltage and head and neck (H&N) protocol conditions. These findings suggest that the factors most affecting the CT number are the tube voltage and treatment site (brain and H&N). Gamma index analyses for the 41 retrospective clinical cases, as well as brain metastases and H&N tumors, showed gamma passing rates >90% and <90% for the passing criterion of 2%/2 and 1%/1 mm, respectively. Conclusions: The CT protocol should be carefully decided for TPS. The correct protocol should be used for the corresponding TPS based on the treatment site because this especially affects the dose distribution for brain metastases and H&N tumor recognition. Such steps could help reduce systematic errors.