- Email: [email protected]
Computer-aided diagnosis system for screening of lung cancer
248
Pulmonary Imaging
nodule and the expection of malignant progression of small peripheral adenocarcinoma.
term follow-up of the pdmary lung cancer which 184--• Long showed ground grass opacity nodule on HRCT S. Akata, Y. Ohkubo, J. Park, D. Kakizaki, K. Abe, H. Kato. Dept. of
Radiology and Dept. of Surgery, Tokyo Medical University, Tokyo, Japan
[8-•
Localized pure ground-glass opacity on high-resolution CT: Histological characteristics
R. Nakajima, T. Yokose, R. Kakinuma, K. Nagai, Y. Nishiwaki, A. Ochiai. Thoracic Oncology; National Cancer Center East Hospital;
Pathology Division, National Cancer Center Reserch Institute East, Kashiwa-shi, Japan
Purpose: The aim of this study is to assess the histologic characteristics in the cases of the localized pure ground glass opacity (LPGGO) findings that do not exhibit consolidation on high-resolution CT images. Materials and Methods: Twenty-three surgically resected lesions from 19 consecutive cases seen between January 1996 and July 1999 were retrospectively investigated. Each of the 23 lesions had exhibited LPGGO findings on HRCT images. The HRCT images and histopathological findings were examined for correlations. Results: The areas of LPGGO had a maximum diameter of 2.02.4 mm on the HRCT images. Histopathology of the LPGGO lesions resulted in diagnosis of fibrosis (n = 3, 13.0%), atypical adenomatous hyperplasia (AAH) (n = 5, 21.7%), bronchioloalveolarcarcinoma (BAC) (n = 12, 52.2%), and adenocarcinoma with stromal invasion (Ad) (n = 3, 13.1%). Non-aerogenous components corresponding solid components, such as lymph follicles, collapsed alveoli, and fibrotic focis without normal alveolar septal destruction, were pathologically observed in 17 of the 23 lesions. The diameter of the non-aerogenous components varied between 0.2-2.0 mm. Discussion: Non-aerogenous components with a diameter of less than 2 mm could not be detected in more than 60% of the cases. Since the LPGGO findings corresponded histologically not only to fibrosis, AAH and BAC but also to Ad, patients with LPGGO findings should undergo partial resection for pathologically confirmation.
~-~
Evaluation of computer-assisted diagnosis of small pulmonary nodules using contrast-enhanced dynamic helical CT
K. Mori, T. Yoshida, Y. Kamiyama, K. Tominaga, K. Yokoi, N. Takagi 1, Y. Kawata1, N. Niki 1, N. Moriyama2, Dept. of Thoracic Diseases,
Tochigi Cancer Center, Tochigi; 1Tokushima University; 2National Cancer Center, Japan As an application of computer-assisted qualitative diagnostic, support for small pulmonary nodules, the contrast enhancement of lesions over time in dynamic helical contrast CT images was evaluated quantitatively in an attempt to differentiate between benign and malignant lesions. The subjects included 20 patients with small pulmonary nodules (including 7 patients with malignant lesions). Scanning was performed with a beam width of 2 ram, a pitch of 1, and a tube current of 250 mA. Helical scanning of the entire lesion was performed before and 2 and 4 minutes after the administration of 100 mL of contrast agent at a rate of 2 mL/s, and images were reconstructed at 1 mm intervals. A special alignment algorithm was used to generate pre- and post-contrast images in which the all slice surfaces of the lesion were closely matched. Contrast enhancement was evaluated by measuring CT values at the center of the lesion and calculating the differences between pre- and post-contrast CT images. The contrast effects were 22 HU (4-42) for benign lesions, and 54 HU (45-60) for malignant lesions. If nodules showing contrast enhancement of 40 HU or higher are considered malignant, the method's sensitivity, specificity, and accuracy are calculated to be 100%, 85%, and 90%, respectively. We conclude that the measurement of CT values of small pulmonary nodules over time using contrast-enhanced dynamic helical CT is useful for the identification of malignant lesions.
Most ground grass opacity (GGO) nodules on high-resorution computed tomography (HRCT) are reported to be early well-differentiated adenocarcinoma, however, these are not specific findings. Although the detection of GGO nodules increases with the use of CT on checkups, diagnosis is difficult even by biopsy. The progress of HRCT findings in lung cancer showing GGO nodules was evaluated. The GGO nodules were present in 7 cases of primary lung cancer. HRCT findings of 8 lesions in 7 cases were examined for 40 days or more. Every operated case was identified as well-differentiated adenocarcinoma pathologically. HRCT did not demonstrate any increase in size or change in shape of any GGO nodules, and no changes in internal density, air bronchogram or surrounding structures were depicted either. Even primary lung cancer, no change in GGO nodules on HRCT was recognized for a long period. This paper suggests that in GGO nodules without any change on long term follow-up on HRCT the possibility of welt-differentiated adenocarcinoma should be considered.
~-4-~ Lung cancer screening using low dose spiral CT T. Nawa, T. Nakagawa, Y. Sugawara, H. Nakata1. Hitachi Health
Care Center, Hitachi. Ltd.; I Department of Radiology, University of Occupational and Environmental Health, Japan Early detection of lung cancer using computed tomography (Thoracic CT screening) is expected that play a important role to decrease mortality of primary lung cancer. We have developed a screening program with low dose spiral CT as a part of periodic (annual) medical examination for the employees, retired employees, and their spouses belonging to one occupational health insurance society. From April 1998 and December 1999, 9105 individuals (7060 males and 2045 females) aged between 49 and 69 underwent annual medical examinations. Among 9105 individuals, 6742 were received CT screening for the first time, and 2363 had been received twice. Low dose CT (tube current 50 mA, tube voltage 120 kVp, 1 0 mm collimation, 2:1 pitch) of the thorax was performed, and two reading doctors (radiologists or physician) interpreted the scans on monitors separatery. Conference of reading doctors were developed weekly to assess the classification. Lung abnormality were found in 321 indivisuals (5.0%). Detailed CT scans (e.g. High Resolution CT) were executed initially as diagnostic workup, and 57 individuals had been needed further examinations. A thoracotomy was carried out in 40 cases, and cancer was confirmed 31 patients (32 lesions, 0.35%). Twenty eight patients were stage IA, and twenty seven lesions were less than 20 mm in diameter. These data suggests that low dose spiral CT is very effective tool to detect small lung cancer.
l-8-~ Computer-aided diagnosis system for screening of lung cancer T. NakagawaI , T. NawaI , Y. SugawaraI , S. Yamamoto 2, T. Matsurnoto3, Y. Gotoh4. 1Hitachi Health Care Center, Hitachi Ltd.,
Hitachi; 2 Toyohashi University of Technology, Toyohashi; 3National Institute of Radiological Science, Chiba; 4Hitachi Medical Corporation, Kashiwa, Japan We examined 9105 persons (7060 men, 2045 women; range 50-69 years old) from April 1996 to December 1999 by low-dose spiral CT for screening of lung cancer. Two doctors (radiologists or a physician) read CT image independently. When the two readers could not reach consensus, the final decision was made at a weekly conference. It is too hard to read a lot of screening images. Therefore, it is necessary to develop a Computer-Aided Diagnosis (CAD) system.
Pulmona~ Imaging Our CAD system consists of the automatic processing part and the image based diagnosis part. The automatic processing part is to detect the candidate lesions of lung cancer based on the methods we proposed. Doctors are operating the image based diagnosis part to make screening works. The position and number of candidate lesion are displayed on the main window, and color rings indicating candidate lesion are superimposed on gray image of result window. A Doctor gives final decision by integrated results carefully. We are evaluating and improving this system continually, and in the near future, we'll propose a new style of lung cancer screening with our CAD system.
~-~
Usefulness of spiral CT scan for early detection of lung cancer our experience at the Anti-Lung Cancer Association (ALCA)
H. Nishiyama 1'2, M. Kaneko 3, H. Ohmatsu 4, R. Kakinuma 4, M. Kusumoto 3, J. Misawa 1, E. Matsui 1, K. Eguchi 5, T. Sobue 6, N. Moriyama 3. I Anti-Lung Cancer Association (ALCA); 2Social
Health Insurance Medical Center; 3National Cancer Center Hospital, 4National Cancer Center Hospital East; 5National Shikoku Cancer Center Hospital; 6National Cancer Center Research Institute, Japan Introduction: The Anti-Lung Cancer Association (ALCA) was established in 1975 for the purpose of detecting lung cancer in its early stage. We have been performing physical examination, frontal and lateral chest radiography, and sputum cytologic studies for 3 consecutive days on a membership basis twice a year. Notable results have been obtained since 1993 when we began to use spiral CT scan in the primary examinations. Discussion on its usefulness follows. Result: We diagnosed 82 cases of lung cancer by August, 1999. After the introduction of spiral CT scan, altogether 10,807 examinations were carried out for 1,500 members and 39 cases of lung cancer were found out, giving the detection rate of 361 per 100,000 cases. Detection was made by sputum cytology in 8 (4 of the 8 were discovered only by cytology), by chest x-ray in 8 (all were also shown on CT films) and by CT scan in 34 cases. As for staging, there were 31 cases in the Stage I A and 1 case in Stage I B and II A, 2 cases in IliA and IIIB respectively, and 1 case in Stage IV. Apparently, the proportion of Stage I A to the total cases was higher after the introduction of spiral CT scan than before. Regarding the type of the tumors, 5 cases were of central type (all cases turned out to be squamous cell carcinoma) and the others were of peripheral type (27 cases were adenocarcinoma, 11 cases were squamous cell carcinoma and 1 case was small cell carcinoma). The average diameter of the lung cancers was 16 mm in all, whereas the cancers detected by CT scan were markedly smaller with the average diameter being 12.5 mm. The-5 year survival rate of 39 cases detected after the introduction of spiral CT scan was 82.6% and significantly higher than before (48.8%). Summary: Our lung cancer screening program with spiral CT scan revealed more positive cases than without it. The tumors detected with the CT scan were much smaller in size and earlier in stage and significantly higher in the 5-year survival rate than without it. ~-~
Early radiological changes in squamous cell lung carcinoma patients treated with split-course radiotherapy as revealed by CT
S.A. Koruzhik, V.A. Ovchinnikov 2, O.S. Dovnar 1. Roentgeno/ogy
Department; 1Radiation Onco/ogy Department; Grodno Regional Clinical Hospital; 2Chair of Oncology, Roengenology and Radiation Oncology, Grodno State Medical University, Grodno, Belarus Squamous cell lung carcinoma (SqCLC) is known radioresistant type of lung cancer and may be used as indicator of efficacy of radiotherapy (RT) regimen. 26 patients with inoperable SqCLC received photon (Xray) irradiation given as split-course. At the fist stage 28 Gy were delivered in 10 days with two 2 Gy fractions daily 5 days a week. 3 to 4 weeks after the end of the first stage second one was initiated with the similar design: 30 Gy in 3 weeks with two 1 Gy fractions
249
daily. Two CT exams were performed in all patients: first one before treatment for staging purposes and CT assisted RT planing; second CT scan - precisely before second stage of RT both to plan irradiation and to examine early tumor regression. For that purpose product of the two longest perpendicular diameters of the lesion and the grade of bronchial obstruction were compared between first and second scans. Third CT scan was performed in 16 patients 4 to 11 weeks after the end of RT to reveal acute radiation-induced lung injury. It was not possible to measure lesion at the initial CT scan in 5 patients because of atelectasis and only slight bronchial wall thickening was revealed in one another patient. In the remaining 20 patients tumor regression rates 4 weeks after the first RT stage were as the next: complete disappearance of the lesion was observed in 3 patients, >50% reduction in 4, >25% reduction in 3, <25% reduction in 3, no change in 7. There were no cases of the increase of the lesion. Considerable improvement of bronchial obstruction grade (that is atelectasis transition to hypoventilation/normal ventilation or hypoventilation to transition normal ventilation) after the first RT stage was observed in 15 of 19 patients who had bronchial obstruction initially. No radiationinduced lung injury were detected in 5 of 16 patients, slight increase in attenuation in 7, patchy consolidation in 2 and discrete consolidation in 2. In summary, in SqCLC patients treated with split-course RT initial tumor regression was achieved in 13 of 20 patients (65%) and some acute radiation-induced lung injury was detected in 11 of 16 patients (69%).
•
5
3
•
A
new mass screening project for lung cancer with mobile spiral computed tomography (CT) & computed radiography (CR) in Ehime District, Japan
T. Takahashi. Anti-lung Cancer Group in Ehime, Japan In Japan, mass screening for lung cancer has been widely performed using minified chest radiographs (10 × 10 cm) for high risk groups. However, the mortality from lung cancer has increased gradually. We started the new mass screening project for lung cancer with mobile spiral CT & CR since November, 1999. This project is intended for the detection of early lung cancer in general population of Ehime Prefecture. The number of the subjects examined with this CT and CR is expected to be 5,000 and 20,000 annually for three years, respectively The digital data obtained from CT and CR are collected and managed at the central office, and are planning to be sent with on-line to five hospitals, where the images are diagnosed by chest radiologists and physicians. The criteria for the diagnosis of lung cancer are based on the size and characteristics of the nodules. Nodules detected on screening CT, they are examined with thin-section CT. When there is no definitive sign of benign lesions, the nodules are managed according to the size of the nodules. When the nodule is less than 5 mm in diameter, it is followed up with thin-section CT at 3, 6, and 12 months intervals to estimate the precise change of the size of the nodule. In case of the nodule with over 10 mm in diameter, the nodule should be diagnosed with biopsy or video-assisted surgery. When the nodule with 5 to 10 mm in diameter, follow up or biopsy is recommended according to the characteristics of the nodule. Chest radiologists and physicians have a meeting once a month to make consensus in the criteria for diagnosing the nodules in this project. Furthermore, doctors, technicians, physicists, and other stuffs who related to the management of this project have a meeting periodically, dealing with the problems such as human network, reporting system, on-line system, follow-up methods, accountability and patient counseling etc. Thus, this unique project for lung cancer screening has just started, and we would like to present the system itself and the preliminary results.
Pulmonary Imaging
nodule and the expection of malignant progression of small peripheral adenocarcinoma.
term follow-up of the pdmary lung cancer which 184--• Long showed ground grass opacity nodule on HRCT S. Akata, Y. Ohkubo, J. Park, D. Kakizaki, K. Abe, H. Kato. Dept. of
Radiology and Dept. of Surgery, Tokyo Medical University, Tokyo, Japan
[8-•
Localized pure ground-glass opacity on high-resolution CT: Histological characteristics
R. Nakajima, T. Yokose, R. Kakinuma, K. Nagai, Y. Nishiwaki, A. Ochiai. Thoracic Oncology; National Cancer Center East Hospital;
Pathology Division, National Cancer Center Reserch Institute East, Kashiwa-shi, Japan
Purpose: The aim of this study is to assess the histologic characteristics in the cases of the localized pure ground glass opacity (LPGGO) findings that do not exhibit consolidation on high-resolution CT images. Materials and Methods: Twenty-three surgically resected lesions from 19 consecutive cases seen between January 1996 and July 1999 were retrospectively investigated. Each of the 23 lesions had exhibited LPGGO findings on HRCT images. The HRCT images and histopathological findings were examined for correlations. Results: The areas of LPGGO had a maximum diameter of 2.02.4 mm on the HRCT images. Histopathology of the LPGGO lesions resulted in diagnosis of fibrosis (n = 3, 13.0%), atypical adenomatous hyperplasia (AAH) (n = 5, 21.7%), bronchioloalveolarcarcinoma (BAC) (n = 12, 52.2%), and adenocarcinoma with stromal invasion (Ad) (n = 3, 13.1%). Non-aerogenous components corresponding solid components, such as lymph follicles, collapsed alveoli, and fibrotic focis without normal alveolar septal destruction, were pathologically observed in 17 of the 23 lesions. The diameter of the non-aerogenous components varied between 0.2-2.0 mm. Discussion: Non-aerogenous components with a diameter of less than 2 mm could not be detected in more than 60% of the cases. Since the LPGGO findings corresponded histologically not only to fibrosis, AAH and BAC but also to Ad, patients with LPGGO findings should undergo partial resection for pathologically confirmation.
~-~
Evaluation of computer-assisted diagnosis of small pulmonary nodules using contrast-enhanced dynamic helical CT
K. Mori, T. Yoshida, Y. Kamiyama, K. Tominaga, K. Yokoi, N. Takagi 1, Y. Kawata1, N. Niki 1, N. Moriyama2, Dept. of Thoracic Diseases,
Tochigi Cancer Center, Tochigi; 1Tokushima University; 2National Cancer Center, Japan As an application of computer-assisted qualitative diagnostic, support for small pulmonary nodules, the contrast enhancement of lesions over time in dynamic helical contrast CT images was evaluated quantitatively in an attempt to differentiate between benign and malignant lesions. The subjects included 20 patients with small pulmonary nodules (including 7 patients with malignant lesions). Scanning was performed with a beam width of 2 ram, a pitch of 1, and a tube current of 250 mA. Helical scanning of the entire lesion was performed before and 2 and 4 minutes after the administration of 100 mL of contrast agent at a rate of 2 mL/s, and images were reconstructed at 1 mm intervals. A special alignment algorithm was used to generate pre- and post-contrast images in which the all slice surfaces of the lesion were closely matched. Contrast enhancement was evaluated by measuring CT values at the center of the lesion and calculating the differences between pre- and post-contrast CT images. The contrast effects were 22 HU (4-42) for benign lesions, and 54 HU (45-60) for malignant lesions. If nodules showing contrast enhancement of 40 HU or higher are considered malignant, the method's sensitivity, specificity, and accuracy are calculated to be 100%, 85%, and 90%, respectively. We conclude that the measurement of CT values of small pulmonary nodules over time using contrast-enhanced dynamic helical CT is useful for the identification of malignant lesions.
Most ground grass opacity (GGO) nodules on high-resorution computed tomography (HRCT) are reported to be early well-differentiated adenocarcinoma, however, these are not specific findings. Although the detection of GGO nodules increases with the use of CT on checkups, diagnosis is difficult even by biopsy. The progress of HRCT findings in lung cancer showing GGO nodules was evaluated. The GGO nodules were present in 7 cases of primary lung cancer. HRCT findings of 8 lesions in 7 cases were examined for 40 days or more. Every operated case was identified as well-differentiated adenocarcinoma pathologically. HRCT did not demonstrate any increase in size or change in shape of any GGO nodules, and no changes in internal density, air bronchogram or surrounding structures were depicted either. Even primary lung cancer, no change in GGO nodules on HRCT was recognized for a long period. This paper suggests that in GGO nodules without any change on long term follow-up on HRCT the possibility of welt-differentiated adenocarcinoma should be considered.
~-4-~ Lung cancer screening using low dose spiral CT T. Nawa, T. Nakagawa, Y. Sugawara, H. Nakata1. Hitachi Health
Care Center, Hitachi. Ltd.; I Department of Radiology, University of Occupational and Environmental Health, Japan Early detection of lung cancer using computed tomography (Thoracic CT screening) is expected that play a important role to decrease mortality of primary lung cancer. We have developed a screening program with low dose spiral CT as a part of periodic (annual) medical examination for the employees, retired employees, and their spouses belonging to one occupational health insurance society. From April 1998 and December 1999, 9105 individuals (7060 males and 2045 females) aged between 49 and 69 underwent annual medical examinations. Among 9105 individuals, 6742 were received CT screening for the first time, and 2363 had been received twice. Low dose CT (tube current 50 mA, tube voltage 120 kVp, 1 0 mm collimation, 2:1 pitch) of the thorax was performed, and two reading doctors (radiologists or physician) interpreted the scans on monitors separatery. Conference of reading doctors were developed weekly to assess the classification. Lung abnormality were found in 321 indivisuals (5.0%). Detailed CT scans (e.g. High Resolution CT) were executed initially as diagnostic workup, and 57 individuals had been needed further examinations. A thoracotomy was carried out in 40 cases, and cancer was confirmed 31 patients (32 lesions, 0.35%). Twenty eight patients were stage IA, and twenty seven lesions were less than 20 mm in diameter. These data suggests that low dose spiral CT is very effective tool to detect small lung cancer.
l-8-~ Computer-aided diagnosis system for screening of lung cancer T. NakagawaI , T. NawaI , Y. SugawaraI , S. Yamamoto 2, T. Matsurnoto3, Y. Gotoh4. 1Hitachi Health Care Center, Hitachi Ltd.,
Hitachi; 2 Toyohashi University of Technology, Toyohashi; 3National Institute of Radiological Science, Chiba; 4Hitachi Medical Corporation, Kashiwa, Japan We examined 9105 persons (7060 men, 2045 women; range 50-69 years old) from April 1996 to December 1999 by low-dose spiral CT for screening of lung cancer. Two doctors (radiologists or a physician) read CT image independently. When the two readers could not reach consensus, the final decision was made at a weekly conference. It is too hard to read a lot of screening images. Therefore, it is necessary to develop a Computer-Aided Diagnosis (CAD) system.
Pulmona~ Imaging Our CAD system consists of the automatic processing part and the image based diagnosis part. The automatic processing part is to detect the candidate lesions of lung cancer based on the methods we proposed. Doctors are operating the image based diagnosis part to make screening works. The position and number of candidate lesion are displayed on the main window, and color rings indicating candidate lesion are superimposed on gray image of result window. A Doctor gives final decision by integrated results carefully. We are evaluating and improving this system continually, and in the near future, we'll propose a new style of lung cancer screening with our CAD system.
~-~
Usefulness of spiral CT scan for early detection of lung cancer our experience at the Anti-Lung Cancer Association (ALCA)
H. Nishiyama 1'2, M. Kaneko 3, H. Ohmatsu 4, R. Kakinuma 4, M. Kusumoto 3, J. Misawa 1, E. Matsui 1, K. Eguchi 5, T. Sobue 6, N. Moriyama 3. I Anti-Lung Cancer Association (ALCA); 2Social
Health Insurance Medical Center; 3National Cancer Center Hospital, 4National Cancer Center Hospital East; 5National Shikoku Cancer Center Hospital; 6National Cancer Center Research Institute, Japan Introduction: The Anti-Lung Cancer Association (ALCA) was established in 1975 for the purpose of detecting lung cancer in its early stage. We have been performing physical examination, frontal and lateral chest radiography, and sputum cytologic studies for 3 consecutive days on a membership basis twice a year. Notable results have been obtained since 1993 when we began to use spiral CT scan in the primary examinations. Discussion on its usefulness follows. Result: We diagnosed 82 cases of lung cancer by August, 1999. After the introduction of spiral CT scan, altogether 10,807 examinations were carried out for 1,500 members and 39 cases of lung cancer were found out, giving the detection rate of 361 per 100,000 cases. Detection was made by sputum cytology in 8 (4 of the 8 were discovered only by cytology), by chest x-ray in 8 (all were also shown on CT films) and by CT scan in 34 cases. As for staging, there were 31 cases in the Stage I A and 1 case in Stage I B and II A, 2 cases in IliA and IIIB respectively, and 1 case in Stage IV. Apparently, the proportion of Stage I A to the total cases was higher after the introduction of spiral CT scan than before. Regarding the type of the tumors, 5 cases were of central type (all cases turned out to be squamous cell carcinoma) and the others were of peripheral type (27 cases were adenocarcinoma, 11 cases were squamous cell carcinoma and 1 case was small cell carcinoma). The average diameter of the lung cancers was 16 mm in all, whereas the cancers detected by CT scan were markedly smaller with the average diameter being 12.5 mm. The-5 year survival rate of 39 cases detected after the introduction of spiral CT scan was 82.6% and significantly higher than before (48.8%). Summary: Our lung cancer screening program with spiral CT scan revealed more positive cases than without it. The tumors detected with the CT scan were much smaller in size and earlier in stage and significantly higher in the 5-year survival rate than without it. ~-~
Early radiological changes in squamous cell lung carcinoma patients treated with split-course radiotherapy as revealed by CT
S.A. Koruzhik, V.A. Ovchinnikov 2, O.S. Dovnar 1. Roentgeno/ogy
Department; 1Radiation Onco/ogy Department; Grodno Regional Clinical Hospital; 2Chair of Oncology, Roengenology and Radiation Oncology, Grodno State Medical University, Grodno, Belarus Squamous cell lung carcinoma (SqCLC) is known radioresistant type of lung cancer and may be used as indicator of efficacy of radiotherapy (RT) regimen. 26 patients with inoperable SqCLC received photon (Xray) irradiation given as split-course. At the fist stage 28 Gy were delivered in 10 days with two 2 Gy fractions daily 5 days a week. 3 to 4 weeks after the end of the first stage second one was initiated with the similar design: 30 Gy in 3 weeks with two 1 Gy fractions
249
daily. Two CT exams were performed in all patients: first one before treatment for staging purposes and CT assisted RT planing; second CT scan - precisely before second stage of RT both to plan irradiation and to examine early tumor regression. For that purpose product of the two longest perpendicular diameters of the lesion and the grade of bronchial obstruction were compared between first and second scans. Third CT scan was performed in 16 patients 4 to 11 weeks after the end of RT to reveal acute radiation-induced lung injury. It was not possible to measure lesion at the initial CT scan in 5 patients because of atelectasis and only slight bronchial wall thickening was revealed in one another patient. In the remaining 20 patients tumor regression rates 4 weeks after the first RT stage were as the next: complete disappearance of the lesion was observed in 3 patients, >50% reduction in 4, >25% reduction in 3, <25% reduction in 3, no change in 7. There were no cases of the increase of the lesion. Considerable improvement of bronchial obstruction grade (that is atelectasis transition to hypoventilation/normal ventilation or hypoventilation to transition normal ventilation) after the first RT stage was observed in 15 of 19 patients who had bronchial obstruction initially. No radiationinduced lung injury were detected in 5 of 16 patients, slight increase in attenuation in 7, patchy consolidation in 2 and discrete consolidation in 2. In summary, in SqCLC patients treated with split-course RT initial tumor regression was achieved in 13 of 20 patients (65%) and some acute radiation-induced lung injury was detected in 11 of 16 patients (69%).
•
5
3
•
A
new mass screening project for lung cancer with mobile spiral computed tomography (CT) & computed radiography (CR) in Ehime District, Japan
T. Takahashi. Anti-lung Cancer Group in Ehime, Japan In Japan, mass screening for lung cancer has been widely performed using minified chest radiographs (10 × 10 cm) for high risk groups. However, the mortality from lung cancer has increased gradually. We started the new mass screening project for lung cancer with mobile spiral CT & CR since November, 1999. This project is intended for the detection of early lung cancer in general population of Ehime Prefecture. The number of the subjects examined with this CT and CR is expected to be 5,000 and 20,000 annually for three years, respectively The digital data obtained from CT and CR are collected and managed at the central office, and are planning to be sent with on-line to five hospitals, where the images are diagnosed by chest radiologists and physicians. The criteria for the diagnosis of lung cancer are based on the size and characteristics of the nodules. Nodules detected on screening CT, they are examined with thin-section CT. When there is no definitive sign of benign lesions, the nodules are managed according to the size of the nodules. When the nodule is less than 5 mm in diameter, it is followed up with thin-section CT at 3, 6, and 12 months intervals to estimate the precise change of the size of the nodule. In case of the nodule with over 10 mm in diameter, the nodule should be diagnosed with biopsy or video-assisted surgery. When the nodule with 5 to 10 mm in diameter, follow up or biopsy is recommended according to the characteristics of the nodule. Chest radiologists and physicians have a meeting once a month to make consensus in the criteria for diagnosing the nodules in this project. Furthermore, doctors, technicians, physicists, and other stuffs who related to the management of this project have a meeting periodically, dealing with the problems such as human network, reporting system, on-line system, follow-up methods, accountability and patient counseling etc. Thus, this unique project for lung cancer screening has just started, and we would like to present the system itself and the preliminary results.