• Korean Journal of Head & Neck Oncology
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• v.26 no.2
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• pp.193-197
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• 2010

Objectives : Patients with neck tumor and their family need every information about the disease. Especially, the size and location are confusing with verbal information. With the aid of CT, the problem had some answer, but it needs some medical education. We would like to know the usefullness of 3D reconstructed images in patient education about the disease. Material and Methods : Neck CT data were collected from 10 patients with various neck tumors and converted to 3D reconstructed images. Understanding of the patients about the size and location of tumors were rated from questionaires using axial CT images and 3D images. Results : Understanding score about 3D images were greater than that of CT images(p<0.006). Conclusion : 3D reconstructed images of CT could give the patients more real visual information about the disease.

• Korean Journal of Head & Neck Oncology
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• v.4 no.1
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• pp.5-11
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• 1988

CT examination has been used in the preoperative examination of patients with head and neck cancer. The accuracy of CT in detecting nodal metastases has not been well established. We studied 35 patients (41 neck specimens) with head and neck cancer who underwent neck dissection. Surgical pathologic findings were compared with preoperative CT scan to establish the diagnostic accuracy for cervical lymph node metastases. The results of physical examination, CT scans of neck and histologic examinations were compared each other. The overall diagnostic accuracy of CT was 83.3%. Comparison with clinical accuracy shows the CT scan to be superior to the clinical examination in spite of careful physical examination, particularly in detecting occult metastases.

• Korean Journal of Head & Neck Oncology
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• v.15 no.2
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• pp.166-171
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• 1999

Background and Objectives: The aim of our study was to describe the appearance of recurrent and residual lesions in the head and neck tumors, and to evaluate the usefullness of CT and MRI. Materials and Methods: CT(n=42) and MRI(n=4) of 44 patients with recurrent head and neck tumors were reviewed retrospectively. Primary tumor sites were larynx/hypopharynx in 15, oral cavity/floor of mouth in 13, base of tongue/tonsil in 5, nasopharynx in 4, palate in 2, and others in 5 patients. Therapeutic modalities included sugery and radiotherapy in 23, radiotherapy in 11, surgery in 5, chemotherapy and radiotherapy in 4, and chemotherapy in 1 patient. Results: The patterns of tumor recurrence were nodal recurrence(n=17), primary tumor bed recurrence combined with nodal recurrence(n=12), primary tumor bed recurrence(n=10) and residual primary tumors(n=5). The most common appearance of residual/recurrent primary tumor on CT was focal or diffuse heterogenous mass with or without surrounding fat or muscle infiltration(25/27). On MRI, the recurrent lesions showed intermediate signal intensity on T1 weighted image and high signal intensity on T2 weighted image with heterogenous enhancement in the most cases(n=3). 38 out of 44 nodal recurrences(86%) which had been pathologically or clinically proved were more than 1 cm in diameter or contained central low density on CT scan. Conclusion: Although CT and MRI findings of recurrent and residual tumors of the head and neck were nonspecific, in the majority the lesions manifested as a mass at primary tumor bed and/or nodal disease including contralateral side of the neck. And CT and MRI are valuable for revealing above lesions.

• Korean Journal of Head & Neck Oncology
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• v.26 no.2
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• pp.178-182
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• 2010

서 론 : 두경부암의 예후에 가장 중요한 인자는 진단시 병기와 치료 후 재발의 유무이다. 따라서, 재발 병변을 조기에 발견하는 것이 매우 중요하다. 본 연구에서는 두경부암 환자의 추적 관찰에서 $^{18}F$-FDG PET/CT의 유용성에 대해 알아보고자 하였다. 대상 및 방법 : 2004년 4월부터 2008년 8월까지 고려대 안암병원에서 두경부암으로 치료를 완료한 후 추적관찰이 가능하였던 88 예의 환자를 대상으로 하였다. 환자는 본원의 두경부암 추적관찰 양식에 따라 술 후 6, 12개월째 $^{18}F$-FDG PET/CT를 시행하였으며, 원발부위 및 경부 재발, 원격전이와 중복암의 진단에 있어 $^{18}F$-FDG PET/CT의 민감도, 특이도, 양성예측율, 음성예측율을 평가하였고, 기존의 추적관찰 방법과 이를 비교하였다. 결 과 : 원발부위 재발의 진단에 있어 민감도, 특이도, 양성예측율, 음성예측율은 각각 95%, 97%, 90%, 98% 였다. 경부전이 재발의 진단에 있어서는 각각 94%, 98%, 83%, 99%였으며, 원격전이 및 이차암 진단에 있어서는 94%, 100%, 100%, 99%였다. 원발부위 재발은 고식적인 진단 방법, 원격전이와 이차암은 $^{18}F$-FDG PET/CT가 진단에 의미있게 유리하였다. 결 론 : $^{18}F$-FDG PET/CT는 두경부암의 추적관찰 과정에서 재발 여부를 판정하는데 있어 매우 유용하며, 특히 원격전이 및 이차암의 발견에 있어 유용하다. 그러나, 위양성 및 위음성의 가능성으로 고식적인 진단 방법과 병행해야 진단의 효과를 높힐 것으로 생각된다.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.18 no.1
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• pp.67-70
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• 2007

Background and Objectives: The nonrecurrent laryngeal nerve(NRLN) is exceedingly rare nerve anomaly that is associated with developmentally aberrant subclavian artery. The presence of NRLN is associated with an increased risk of vocal cord palsy in thyroid surgery. The purpose of this study is to investigate its prevalence, associated vascular anomaly and necessity of recognizing its possibility for prevention of intraoperative nerve damage. Materials and Methods: Between January 2004 and December 2006, 583 thyroidectomy were performed at our hospital. Of these cases, 529 cases(90.7%) were checked preoperative neck CT. Results: Patients with preopreative neck CT, 6 cases show the retroesophageal abberant right subclavian artery that arising directly form the aortic arch. 5 cases of these 6 cases(5/6, 83.3%) and of 583 patients(5/583, 0.8%) performed thyroid surgery were identified NRLN per-operatively. All of them are identified on the right side. There were 4 women and 1 man. In all cases, there were no clinical symptoms. I case was performed only left hemithyroidectomy, so we cannot identified NRLN. No vocal cord palsy was observed. Conclusion: It is possible to predict NRLN from preoperative neck CT. When NRLN is suspected, careful, complete dissection of the nerve is always advocated. These process can reduce the operative morbidity.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.2
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• pp.85-95
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• 2010

Purpose: The degradation of an image quality and error of the beam dose calculation can be caused because the metal artifact is generated during the CT simulation of head and neck patient. The usability of the gantry tilt scan for reducing the metal artifact tries to be appraised. Materials and Methods: The inferior $20^{\circ}$ gantry tilt scan was made in order to reduce the metal artifact and $0^{\circ}$ reconstruction image was acquired. The AAPM CT performance Phantom was used in order to compare the CT number of the reconstructed image and Original image. the difference of volume was compared by using the acrylic phantom. The homogeneity of the CT number was evaluated the Intensity volume Histogram (IVH) as in order to evaluate an influence by the metal artifact. A dose was evaluated as the Dose Volume Histogram (DVH). Results: in the comparison of the CT number and volume, the difference showed up less than 0.5%. As to the comparison of IVH, in the gantry tilt scan, influence by an artifact was reduced and the homogeneity of the CT number was improved. The comparison of DVH result reduced the mean dose error of the both sides parotid 0.2~6%. Conclusion: In the Head & Neck radiation therapy, It is difficult and to distinguish tumor and normal tissue and the error of dose is generated by the metal artifact. The delineation of the exact organization was possible if the Gantry tilt scan was used. The CT number homogeneity was improved and the error of dose could be reduced. The Gantry tilt scan confirmed in the Head & Neck radiation therapy to be very useful in the exact radiation therapy.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.6
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• pp.309-315
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• 2006

Purpose: Accurate evaluation of cervical lymph node (LN) metastasis of head and neck squamous cell canter (SCC) is important to treatment planning. We evaluated the diagnostic accuracy of F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for the detection of cervical LN metastasis of head and neck SCC and performed a retrospective comparison with CT/MRI findings. Materials & Methods: Seventeen patients with pathologically proven head and neck SCC underwent F-18 FDG PET/CT and CT/MRI within 4 week before surgery. We recorded lymph node metastases according to the neck level system of imaging-based nodal classification. F-18 FDG PET/CT images were analyzed visually for assessment of regional tracer uptake in LN. We analyzed the differences in sensitivity and specificity between F-18 FDG PET/CT and CT/MRI using the Chi-square test. Results: Among the 17 patients, a total of 123 LN levels were dissected, 29 of which showed metastatic involvement. The sensitivity and specificity of F-18 FDG PET/CT for detecting cervical LN metastasis on a level-by-level basis were 69% (20/29) and 99% (93/94). The sensitivity and specificity of CT/MRI were 62% (18/29) and 96% (90/94). There was no significant difference in diagnostic accuracy between F-18 FDG PET/CT and CT/MRI. Interestingly, F-18 FDG PET/CT detected double primary tumor (hepatocellular carcinoma) and rib metastasis, respectively. Conclusion: There was not statistically significant difference of diagnostic accuracy between F-18 FDG PET/CT and CT/MRI for the detection of cervical LN metastasis of head and neck SCC. The low sensitivity of F-18 FDG PET/CT was due to limited resolution for small metastatic deposits.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.2
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• pp.131-143
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• 2015

Purpose : By comparing a CT fusion plan based on MRI with a plan based on only MRI without CT, we intended to study usefulness of a plan based on only MRI. And furthermore, we intended to realize a realtime MR-IGRT by MRI image without CT scan during the course of simulation, treatment planning, and radiation treatment. Materials and Methods : BBB CT (Brilliance Big Bore CT, 16slice, Philips), Viewray MRIdian system (Viewray, USA) were used for CT & MR simulation and Treatment plan of 11 patients (1 Head and Neck, 5 Breast, 1 Lung, 3 Liver, 1 Prostate). When scanning for treatment, Free Breathing was enacted for Head&Neck, Breast, Prostate and Inhalation Breathing Holding for Lung and Liver. Considering the difference of size between CT and Viewray, the patient's position and devices were in the same condition. Using Viewray MRIdian system, two treatment plans were established. The one was CT fusion treatment plan based on MR image. Another was MR treatment plan including electron density that [ICRU 46] recommend for Lung, Air and Bone. For Head&Neck, Breast and Prostate, IMRT was established and for Lung and Liver, Gating treatment plan was established. PTV's Homogeneity Index(HI) and Conformity Index(CI) were use to estimate the treatment plan. And DVH and dose difference of each PTV and OAR were compared to estimate the treatment plan. Results : Between the two treatment plan, each difference of PTV's HI value is 0.089% (Head&Neck), 0.26% (Breast), 0.67% (Lung), 0.2% (Liver), 0.4% (Prostate) and in case of CI, 0.043% (Head&Neck), 0.84% (Breast), 0.68% (Lung), 0.46% (Liver), 0.3% (Prostate). As showed above, it is on Head&Neck that HI and CI's difference value is smallest. Each difference of average dose on PTV is 0.07 Gy (Head&Neck), 0.29 Gy (Breast), 0.18 Gy (Lung), 0.3 Gy (Liver), 0.18 Gy (Prostate). And by percentage, it is 0.06% (Head&Neck), 0.7% (Breast), 0.29% (Lung), 0.69% (Liver), 0.44% (Prostate). Likewise, All is under 1%. In Head&Neck, average dose difference of each OAR is 0.01~0.12 Gy, 0.04~0.06 Gy in Breast, 0.01~0.21 Gy in Lung, 0.06~0.27 Gy in Liver and 0.02~0.23 Gy in Prostate. Conclusion : PTV's HI, CI dose difference on the Treatment plan using MR image is under 1% and OAR's dose difference is maximum 0.89 Gy as heterogeneous tissue increases when comparing with that fused CT image. Besides, It characterizes excellent contrast in soft tissue. So, radiation therapy using only MR image without CT scan is useful in the part like Head&Neck, partial breast and prostate cancer which has a little difference of heterogeneity.

• Korean Journal of Head & Neck Oncology
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• v.26 no.2
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• pp.198-203
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• 2010

Objectives : Getting full information from axial CT images needs experiences and knowledge. Sagittal and coronal images could give more information but we have to draw 3-dimensional images in mind with above informations. With aid of 3D reconstruction softwares, CT data are converted to visible 3D images. We tried to compare medical photographs of 15 surgical specimens from neck tumors with 3D reconstructed images of same patients. Material and Methods : Fifteen patients with neck tumors treated surgically were recruited. Medical photograph of the surgical specimens were collected for comparison. 3D reconstruction of neck CT from same patients with aid of 3D-doctor software gave 3D images of neck masses. Width and height of tumors of each photos and images from the same cases were calculated and compared statistically. Visual similarities were rated between photos and 3D images. Results : No statatistical difference were found in size between medical photos and 3D images. Visual similarity score were higher between 2 groups of images. Conclusion : 3D reconstructed images of neck mass looked alike the real photographs of excised neck mass with similar calculated sizes. It could give us reliable visual information about the mass.

• Korean Journal of Head & Neck Oncology
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• v.26 no.1
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• pp.14-18
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• 2010

Objectives : We evaluated the use of FDG PET/CT for the identification of cervical nodal metastases of SCC of the oral cavity and oropharynx with histological correlation. Material and Methods : We reviewed 46 medical records, from January 2004 to July 2007, of patients who underwent FDG PET/CT and CT/MRI for SCC of the oral cavity and oropharynx before surgery. We recorded the lymph node metastases according to the neck level affected and the system used for the imaging-based nodal classification. Results : The FDG PET/CT had a sensitivity of 75.6% and a specificity of 96.7% ; it had a higher sensitivity than the CT/MRI for identification of cervical metastases on the side of the neck(26/28 vs. 20/28, p=0.031) and at each of the cervical levels(34/45 vs. 26/45, p=0.008). There was a significant difference in the $SUV_{max}$ between the benign and malignant cervical lymph nodes($3.31{\pm}3.23$ vs. $4.22{\pm}2.57$, p=0.028). The receiver-operating-characteristic (ROC) curve analysis for differentiating the benign from the malignant cervical lymph nodes, showed that the area under the curve(AUC) of the FDG PET/CT was 0.775. The cut-off value for the $SUV_{max}$ was 2.23 based on the ROC curve. There was a significant correlation between the $SUV_{max}$ and the size of the cervical lymph nodes(Spearman r=0.353, p=0.048). Conclusion : FDG PET/CT images were more accurate than the CT/MRI images. In addition, the $SUV_{max}$ cut-off values were important for evaluating cervical the cervical nodes in the patients with SCC of the oral cavity and oropharynx.