PURPOSE: Conventional radiation therapy portal images gives low contrast images. The purpose of this study was to enhance image contrast of a linacgram by developing a low-cost image processing method. MATERIALS AND METHODS: Chest linacgram was obtained by irradiating humanoid phantom and scanned using Diagnostic-Pro scanner for image processing. Several types of scan method were used in scanning. These include optical density scan, histogram equalized scan, linear histogram based scan, linear histogram independent scan, linear optical density scan, logarithmic scan, and power square root scan. The histogram distribution of the scanned images were plotted and the ranges of the gray scale were compared among various scan types. The scanned images were then transformed to the gray window by pallette fitting method and the contrast of the reprocessed portal images were evaluated for image improvement. Portal images of patients were also taken at various anatomic sites and the images were processed by Gray Scale Expansion (GSE) method. The patient images were analyzed to examine the feasibility of using the GSE technique in clinic. RESULTS: The histogram distribution showed that minimum and maximum gray scale ranges of 3192 and 21940 were obtained when the image was scanned using logarithmic method and square root method, respectively. Out of 256 gray scale, only 7 to 30% of the steps were used. After expanding the gray scale to full range, contrast of the portal images were improved. Experiment performed with patient image showed that improved identification of organs were achieved by GSE in portal images of knee joint, head and neck, lung, and pelvis. CONCLUSION: Phantom study demonstrated that the GSE technique improved image contrast of a linacgram. This indicates that the decrease in image quality resulting from the dual exposure, could be improved by expanding the gray scale. As a result, the improved technique will make it possible to compare the digitally reconstructed radiographs (DRR) and simulation image for evaluating the patient positioning error.
Head ; Humans ; Knee Joint ; Lung ; Neck ; Patient Positioning ; Pelvis ; Thorax

BACKGROUNDS: The purpose of this study was to identify drugs that can enhance radioresponse of murine hepatocarcinoma. METHODS: C3H/HeJ mice bearing 8 mm tumors of murine hepatocarcinoma, HCa-I, were treated with 25 Gy radiation and one of the following drugs: 5-Fu, 150 mg/kg; adriamycin, 8 mg/kg; cisplatin, 6 mg/kg; paclitaxel, 40 mg/kg; and gemcitabine, 50 mg/kg. Tumor response to the treatment was determined by tumor growth delay assay and by enhancement factor. Apoptotic level was assessed in tissue sections. Expression of regulating molecules was analyzed by western blotting for p53, Bcl-2, Bax, Bcl-XL, Bcl-XS, and p21WAF1/CIP1. RESULTS: Among the drugs tested, only gemcitabine enhanced the antitumor effect of radiation, with enhancement factor of 1.6. Induction of apoptosis by a combination of gemcitabine and radiation was shown as only additive level. In analysis of radiation-induced expression of regulating molecules, the most significant change by combining gemcitabine was activation of p21WAF1/CIP1. CONCLUSION: Gemcitabine is the first drug showing an enhancement of radioresponse in murine hepatocarcinoma, when combined with radiation. The key element of enhancement is thought to be p21WAF1/CIP1.
Animals ; Apoptosis ; Blotting, Western ; Cisplatin ; Doxorubicin ; Drug Therapy* ; Fluorouracil ; Mice ; Paclitaxel ; Radiation Dosage

PURPOSE: To design and test the CT simulator phantom for geometrical test. MATERIAL AND METHODS: The PMMA phantom was designed as a cylinder which is 20 cm in diameter and 24 cm in length, along with a 25x25x31 cm3 rectangular parallelepiped. Radio-opaque wires of which diameter is 0.8 mm are attached on the other surface of the phantom as a spiral. The rectangular phantom was made of four 24x24x0.5 cm3 square plates and each plate had a 24x24 cm2, 12x12 cm2, 6x6 cm2 square line. The squares were placed to face the cylinder at angles 0degrees, 15degrees, 30degrees, respectively. The rectangular phantom made it possible to measure the field size, couch angle, the collimator angle, the isocenter shift and the SSD, the measurements of the gantry angle from the cylindrical part. A virtual simulation software, AcQSimTM, offered various conditions to perform virtual simulations and these results were used to perform the geometrical quality assurance of CT simulator. RESULTS: A 0.3~0.5 mm difference was found on the 24 cm field size which was created with the DRR measurements obtained by scanning of the rectangular phantom. The isocenter shift, the collimator rotation, the couch rotation, and the gantry rotation test showed 0.5~1 mm, 0.5~1degrees0.5~1degrees, and 0.5~ 1degreesdifferences, respectively. We could not find any significant differences between the results from the two scanning methods. CONCLUSION: The geometrical test phantom developed in the study showed less than 1 mm (or 1degrees) differences. The phantom could be used as a routine geometrical QC/QA tools, since the differences are within clinically acceptable ranges.
Polymethyl Methacrylate ; Silver Sulfadiazine

PURPOSE: NOS2 induce NO production and NO activate TGF-beta. The TGF-beta is a inhibitor of NOS2. If this negative feedback mechanism operating in radiation pneumonitis model, NOS2 inhibitor may play a role in TGF-beta suppression. We planned this study to evaluate the expression patterns of NO, NOS2 and TGF-beta in vivo radiation pneumonitis model. MATERIALS AND METHODS: Sixty sprague-Dawley rat were irradiated 5 Gy or 20 Gy. They were sacrificed 3, 7, 14, 28 and 56 days after irradiation. During sacrifice, we performed broncho-alveolar lavage (BAL). The BAL fluids were centrifuged and supernatents were used for measure NO and TGF-beta, and the cells were used for RT-PCR. RESULTS: After 5 Gy of radiation, NO in BAL fluid increased at 28 days in both lung and TGF-beta in left lung at 56 days. NO increased in BAL fluid at 28 days in both lung after irradiation and TGF-beta in right lung at 28-56 days after 20 Gy of radiation. After 5 Gy of radiation, NOS2 expression was increased in right lung at 14 days, in both lung at 28 days and in left lung at 56 days. TGF-beta expression was reduced in both lung at 28 days and increased in left lung at 56 days. CONCLUSIONS: The proposed feedback mechanism of NO, NOS2 and TGF-beta was operated in vivo radiation pneumonitis model. At 56 days, however, NOS2 and TGF-beta expressed concurrently in left lung after 5 Gy and in both lung after 20 Gy of radiation.
Animals ; Lung* ; Radiation Effects* ; Radiation Pneumonitis ; Rats* ; Rats, Sprague-Dawley ; Therapeutic Irrigation ; Transforming Growth Factor beta*

PURPOSE: A new fiduciary plate and orientation marker have been devised to assist the quality assurance (QA) procedures for port films in radiation therapy department. The plate is used in conjunction with the film/cassette combination during weekly QA procedures, at Seoul National University Hospital (SNUH), in order to verify treatment fields in high energy radiation therapy. MATERIALS AND METHODS: A new fiduciary plate was fabricated using an acrylic plate, cerrobend, standard blocking tray and mercury. The acrylic plate had the dimension of 1x25x25 cm, with two fiduciary markers. The plate was rigidly attached onto the standard blocking tray, thus making it easier to set the fiduciary plate to the center of the radiation field of the linear accelerator. The plate had two 2-mm vertical and horizontal lines, with the minor scales in 2-cm steps. The orientation marker was a small mercury filled disk, which was inserted into the plate. RESULTS: The geometrical structure of the lines in the plate makes it easier to correlate two different images between the simulation and port films. The marker clearly indicated the orientation of the film, for example, the anterior, posterior, left, right and various oblique orientations, without the placement of a conventional orientation marker. Also, the new orientation marker could easily be applied to the simulator by placing the small orientation marker onto the image intensifier or in front of the film/cassette holder. CONCLUSIONSs: The new fiduciary plate appears to be useful in verifying the treatment fields, and the new orientation marker makes the film orientation simple, which is expected to lower the block fabrication errors.
Particle Accelerators ; Seoul ; Weights and Measures

PURPOSE: To study the feasibility of verifying real-time 2-D dose distribution measurement system with the scintillation screen for the quality assurance. MATERIALS AND METHODS: The water phantom consisted of a scintillation screen (LANEX fast screen, Kodak, USA) that was axially located in the middle of an acrylic cylinder with a diameter of 25 cm. The charge-coupled device (CCD) camera was attached to the phantom in order to capture the visible light from the scintillation screen. To observe the dose distribution in real time, the intensity of the light from the scintillator was converted to a dosage. The isodose contours of the calculations from RTP and those of the measurements using the scintillation screen were compared for the arc therapy and the intensity modulated radiation therapy (IMRT). RESULTS: The kernel, expressed as a multiplication of two error functions, was obtained in order to correct the sensitivity of the CCD of the camera and the scintillation screen. When comparing the calculated isodose and measured isodose, a discrepancy of less than 8 mm in the high dose region was observed. CONCLUSIONS: Using the 2-D dosimetry system, the relationship between the light and the dosage could be found, and real-time verification of the dose distribution was feasible.
Feasibility Studies* ; Light ; Water

PURPOSE: To evaluate the reflection of tumor motion according to the planning CT scan time. MATERIAL AND METHODS: A model of N-shape, which moved along the longitudinal axis during the ventilation caused by a mechanical ventilator, was produced. The model was scanned by planning CT, while setting the relative CT scan time (T; CT scan time/ventilatory period) to 0.33, 0.50, 0.67, 0.75, 1.00, 1.33 T, and 1.53 T. In addition, three patients with non-small cell lung cancer who received stereotactic radiosurgery in the Department of Radiation Oncology, Asan Medical Center from 03/19/2002 to 05/21/2002 were scanned. Slow (IQ Premier, Picker, scan time 2.0 seconds per slice) and fast CT scans (LightSpeed, GE Medical Systems, with a scan time of 0.8 second per slice) were performed for each patient. The magnitude of reflected movement of the N-shaped model was evaluated by measuring the transverse length, which reflected the movement of the declined bar of the model at each slice. For patients' scans, all CT data sets were registered using a stereotactic body frame scale with the gross tumor volumes delineated in one CT image set. The volume and three-dimensional diameter of the gross tumor volume were measured and analyzed between the slow and fast CT scans. RESULTS: The reflection degree of longitudinal movement of the model increased in proportion to the relative CT scan times below 1.00 T, but remained constant above 1.00 T. Assuming the mean value of scanned transverse lengths with CT scan time 1.00 T to be 100%, CT scans with scan times of 0.33, 0.50, 0.67, and 0.75 T missed the tumor motion by 30, 27, 20, and 7.0% respectively. Slow (scan time 2.0 sec) and Fast (scan time 0.8 sec) CT scans of three patients with longitudinal movement of 3, 5, and 10 mm measured by fluoroscopy revealed the increases in the diameter along the longitudinal axis increased by 6.3, 17, and 23% in the slow CT scans. CONCLUSIONS: As the relative CT scan time increased, the reflection of the respiratory tumor movement on planning CT also increased, but remained constant with relative CT scan times above 1.00 T. When setting the planning CT scan time above one respiration period (>1.00 T), only the set-up margin is needed to delineate the planning target volume. Therefore, therapeutic ratio can be increased by reducing the radiation dose delivered to normal lung tissue.
Axis, Cervical Vertebra ; Carcinoma, Non-Small-Cell Lung ; Chungcheongnam-do ; Dataset ; Fluoroscopy ; Humans ; Lung Neoplasms ; Lung* ; Radiation Oncology ; Radiosurgery ; Respiration ; Tomography, X-Ray Computed* ; Tumor Burden ; Ventilation ; Ventilators, Mechanical

PURPOSE: Captopril (angiotension converting enzyme inhibitor) is known to have a radioprotective effect in the lungs, intestines and skin, but its effect in the heart is unclear. To investigate the radioprotective effect and mechanism of captopril in the heart, the histopathological changes and immunohistochemical stains were compared with radiation alone, and radiation combined with captopril, in the rats. MATERIALS AND METHODS: The histopathological changes and immunohistochemical stains (TNF alpha, TGFbeta1, PDGF and FGF2) were examined in the radiation alone and the combined captopril and radiation groups, 2 and 8 weeks after irradiation. Each group consisted of 8 to 10 rats (Sprague-Dawley). Irradiation (12.5 Gy) was given to the left hemithorax in a single fraction. Captopril (50 mg/Kg/d) mixed with water, was given orally and continuously from the first week prior to, up to the 8th week of the experiment. RESULTS: In the radiation alone group, the ventricle at 2 weeks after irradiation showed prominent edema (p=0.082) and fibrin deposit (p=0.018) compared to the control group. At 8 weeks, the edema was decreased and fibrosis increased compared to those at 2 weeks. The histopathological changes of the combined group were similar to those of the control group, due to the reduced radiation toxicity at 2 and 8 weeks. The endocardial fibrin deposit (p=0.047) in the atrium, and the interstitial fibrin deposit (p=0.019) and edema (p=0.042) of the ventricle were reduced significantly in the combined group compared to those in the radiation alone group at 2 weeks. The expressions of TNF-alpha, TGF-beta1, PDGF and FGF-2 in the radiation alone group were more increased than in the control group, especially in the pericardium and endocardium of the atrium at 2 weeks. At 8 weeks, the pericardial TNF-alpha and TGF-beta1 in the radiation alone group continuously increased. The expressions of TNF-alpha, TGF-beta1 and PDGF were decreased in the combined group at 2 weeks. At 8 weeks, the expressions of TNF-alpha in the atrial and ventricular pericardia were markedly reduced (p=0.049, p=0.009). CONCLUSIONS: This study revealed that the early heart damage induced by radiation can be reduced by the addition of captopril in a rat model. The expressions of TNF-alpha, TGF-beta1 and PDGF were further decreased in the combined compared to the radiation alone group at both 2 and 8 weeks. From these results, it may be concluded that these cytokines probably play roles in the radioprotective mechanism of captopril from the radiation-induced heart toxicity, similarly to in other organs.
Animals ; Captopril* ; Coloring Agents ; Cytokines ; Edema ; Endocardium ; Fibrin ; Fibroblast Growth Factor 2 ; Fibrosis ; Heart ; Intestines ; Lung ; Models, Animal ; Pericardium ; Rats* ; Skin ; Transforming Growth Factor beta1 ; Tumor Necrosis Factor-alpha ; Water

PURPOSE: A tumor registry system for the patients treated by radiotherapy at Samsung Medical Center since the opening of a hospital at 1994 was employed. In this study, the tumor registry system was introduced and the validity of the tumor registration was analyzed. MATERIALS AND METHODS: The tumor registry system was composed of three parts: patient demographic, diagnostic, and treatment information. All data were input in a screen using a mouse only. Among the 10,000 registered cases in the tumor registry system until Aug, 2002, 199 were randomly selected and their registration data were compared with the patients' medical records. RESULTS: Total input errors were detected in 15 cases (7.5%). There were 8 error items in the part relating to diagnostic information: tumor site 3, pathology 2, AJCC staging 2 and performance status 1. In the part relating to treatment information there were 9 mistaken items: combination treatment 4, the date of initial treatment 3 and radiation completeness 2. According to the assignment doctor, the error ratio was consequently variable. The doctors who did no double-checks showed higher errors than those that did (15.6% : 3.7%). CONCLUSIONS: Our tumor registry had errors within 2% for each item. Although the overall data quality was high, further improvement might be achieved through promoting sincerity, continuing training, periodic validity tests and keeping double-checks. Also, some items associated with the hospital information system will be input automatically in the next step.
Animals ; Hospital Information Systems ; Humans ; Medical Records ; Mice ; Pathology ; Quality Control ; Radiation Oncology* ; Radiotherapy ; Data Accuracy

PURPOSE: To evaluate the efficacies and toxicities of concurrent chemoradiotherapy (CCRT), with or without intraluminal brachytherapy (ILB), using a retrospective analysis in esophageal carcinomas with respect to survival. MATERIALS AND METHODS: From April 1995 to July 2001, a total of 65 patients, diagnosed with an esophageal carcinoma, were treated by CCRT, with 21 also treated by ILB after CCRT. External radiotherapy was performed using 6 or 10 MV X-rays, with a dose range of 46.8~69.6 Gy (median; 59.4). The ILB was performed using high-dose-rate brachytherapy with Ir-192. The fractionation of ILB was 3 Gy by 4, or 5 Gy by 2 fractions. Cisplatin (75 mg/m2) was given on each first day of weeks 1, 5, 9 and 13, and 5-FU (1,000 mg/m2) as a continuous infusion for the first 4 days of each course. RESULTS: The median survival time of all patients was 15 months, and the 1, 2 and 3-year survival rates were 55.4, 29.2 and 20.7%, respectively. The 2-year survival rates of the patients with and without ILB were 33.3 and 27.3%, respectively (p=0.80). The 2-year survival rates of the patients with a complete, partial and no response were 44.1, 13.8 and 0%, respectively (p=0.02). The response to treatment was the only significant factor affecting the overall survival from a multivariate analysis. CONCLUSIONS: This study has shown that the survival outcomes of CCRT were much better than previous results with radiotherapy alone. However, the addition of ILB after CCRT showed no advantage over that of CCRT alone.
Brachytherapy* ; Chemoradiotherapy* ; Cisplatin ; Drug Therapy ; Esophageal Neoplasms ; Fluorouracil ; Humans ; Multivariate Analysis ; Radiotherapy ; Retrospective Studies* ; Survival Rate