The Objective Measurement of the Lung Parenchyma Motion for Planning Target Volume Delineation / 대한치료방사선과학회지

PURPOSE: To quantify the movement of lung parenchyma for ICRU 50 Planning Target Volume (PTV) delineation of the lung region. MATERIALS AND METHODS: Fluoroscopic observations and measurements are performed on 10 patients with chest region cancer who have normal pulmonary functions. We have divided the lung region into 12 parts for the right lung, 10 parts for the left lung and four to five points of lung parenchyma were selected for anatomical analysis points. Fluoroscopic images are sent to a computer and then movements are measured. RESULTS: Both lower lobes showed the longest longitudinal movements because of breathing (average 14.1mm, maximum 22.1mm), while antero- posterior displacement showed the smallest value. Lateral movements of the lung parenchyma averaged 6.6mm, and the maximum value was 9.1mm. (both hilar regions showed maximum values because of cardiac motion) CONCLUSION: We could quantify the lung movements by measuring parenchyma displacements. The movements of both upper lobes were less than those of the middle and upper lobes in longitudinal and transverse movements. Optimal margins can be selected for PTV delineation using these results.

Radiation Therapy of Nasopharyngeal Carcinoma / 대한치료방사선과학회지

PURPOSE: This is a retrospective study to evaluate the results of radiation therapy and prognostic factors influencing the results in nasopharyngeal carcinoma. MATERIALS AND METHODS: From October 1989 to May 1996, 56 patients were treated for nasopharyngeal carcinoma at Department of Radiation Oncology. According to stage, patients were distributed as follows: stage I (2), II (13), III (11), IV (30). Twenty-eight patients were treated with radiation therapy only, 7 patients were treated with neoadjuvant chemotherapy followed by radiation therapy. Twenty-one patients were treated with radiation therapy and weekly CDDP. After external beam radiotherapy of 60Gy, 46 patients received boost dose with intracavitary radiation and 9 patients with 3D conformal therapy. One patient received boost dose with 2 dimensional photon beam therapy. The tumor dose ranged from 69.4Gy to 86.2Gy with median dose of 74.4Gy. The follow-up period ranged from 5 months to 92 months with a median of 34 months. RESULTS: Forty-seven patients achieved complete response and 8 patients showed partial response. One patient showed minimal response. Patterns of failure were as follows : locoregional recurrence (8) and distant metastasis (18). Among these patients, 2 patients failed locoregionally and distantly. The sites of distant metastasis were bone (8), lung (8) and liver (4). Five years survival rate was 67.2% and 5 years disease-free survival rate was 53.6%. KPS (P=0.005) and response of radiation therapy (P=0.0001) were significant prognostic factors for overall survival. KPS (P=0.02) and response of radiation therapy (P=0.005) were significant prognostic factors for disease-free survival. CONCLUSION: This retrospective study showed that distant metastasis was the predominant pattern of relapse in nasopharyngeal cancer. Neoadjuvantchemotherapy or weekly CDDP did not influence the distant metastasis-free survival. For advanced T stage, 3D conformal therapy provided an improved dose coverage compared to ICR. But further follow-up was needed in patients with 3D conformal therapy to assess the efficacy of this therapy. Development of techniques of radiation therapy to improve locoregional control and of more effective systemic chemotherapy regimen are needed.

The Rofe of High Dose Rate(HDR) Intracavitary Radiation Therapy for the Management of Nasopharyngeal Carcinoma / 대한치료방사선과학회지

From September 1989 to June 1992, 22 patients with nasopharyngeal carcinoma were treated in Asan Medical Center with an external beam of 60 Gy followed by a boost dose of 15 Gy HDR brachytherapy. There were 5 females and 17 males with median age of 44 years (range: 20-69 years). All patients were histologically confirmed and staged by physical examination, CT scan and/or MRI. By the AJCC TNM staging system, there were 2 patients with stage II (T2NO), 4 with stage III(T3NO, T1-3N1), and 16 with stage IV(T4 or N2-3). Four patients received chemotherapy with 5-FU and cisplatin prior to radiotherapy. All patients were followed up periodically by a telescopic examination and radiologic imaging study of CT scan or MRI with a median follow-up time of 13 months (range: 3-34 mouths). Twenty ore patients showed a complete response one month after completing therapy and one patient showed a complete response after three months. At the time of this analysis, seventeen patients remain alive without evidence of disease, but four patients developed distant metastasis and one patient died a month after treatment. The local control rate was 100% in a median follow-up time of 13 months. The two year overall and disease free survival rates by the Kaplan-Meier method were 94% and 67%, respectively. Serious radiation sequelae have not been observed yet. Although longer follow-up is needed, this retrospective analysis suggests that HDR brachytherap given as a boost therapy for nasoharyngeal carcinoma may improve the local control. To reduce the incidence of distant metastasis, we need to develop a more effective systemic chemotherapy.