• Radiation Oncology Journal
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• v.9 no.1
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• pp.131-141
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• 1991

A comprehensive set of dosimetric measurements has been made on the Varian Clinac 1800 15 MV photon beam. Beam quality, percentage depth dose, dose in the build up region, output, symmetry and flatness, transmission through iead (Cerrobend), tray attenuation, isodose curves for the open and wedged fields were measured using 3 dimensional water phantom dosimetry system (including film densitometer system) and polystyrene phantoms. These dosimetric measurements sufficiently characterized the beam to permit clinical use. The depth dose characteristics of photon beam is $d_{max}$ of 3.0 cm and percentage depth dose of $76.8\%$ at 10 cm,100 cm source-surface distance, field size of $10\times10\;cm^2$ for 15 MV X-ray beam. The Output factors ranged 0.927 for $4\times4\;cm^2$ field to 1,087 for $35\times35\;cm^2$ field. The build-up level of maximum dose was at 3.0 cm and surface dose was approximately $15.5\%$ for a field size $10\times10\;cm^2$ The stability of output is $within\pm1\%$ and flatness and symmetry are $within\pm3\%$. The half value thickness (HVL) of lead is 13 mm, which corresponds to an attenuation coefficient of $0.053\;mm^{-1}$. These figures compare facorably with the manufacturesr`s specifications.

• Radiation Oncology Journal
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• v.27 no.4
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• pp.218-227
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• 2009

Purpose: To investigate the radiobiologic effects of neutron and X-ray irradiation on DU-145 prostate carcinoma cells by identifying the differences of HIF-$1\alpha$ expression and apoptosis. Materials and Methods: Nude mice were injected with the human prostate cancer cell line, DU-145, and then irradiated with 2 Gy and 10 Gy X-rays, or 0.6 Gy and 3.3 Gy neutrons, respectively. The mice were sacrificed at 24 hours and 120 hours after irradiation. The expression levels of HIF-$1\alpha$, Bcl-2 and Bax were compared with immunohistochemical staining and western blotting. The apoptotic indexes were compared with the Terminal deoxynucleotidyl biotin-dUTP nick and labeling (TUNEL) assay. Results: At day 1, HIF-$1\alpha$ and Bcl-2 expression decreased, while Bax expression and the number of TUNEL positive cells increased in neutron irradiated groups for the control and X-ray irradiated groups. The Bcl-2/Bax ratio was significantly lower in the neutron irradiated groups regardless of dose (p=0.001). The same pattern of the differences in the expressions of the HIF-$1\alpha$, Bcl-2, Bax, Bcl-2/Bax ratio, and apoptotic indexes were indentified at day 5. HIF-$1\alpha$ expression was related with Bcl-2 (p=0.031), Bax (p=0.037) expressions and the apoptotic indexes (p=0.016) at day 5. Conclusion: Neutron irradiation showed a decrease in HIF-$1\alpha$, Bcl-2 expression, and Bcl-2/Bax ratio, but increased Bax expression regardless of dose. This study suggests that the differences radiobiological responses between photon and neutron irradiation may be related to different HIF-$1\alpha$ expression and subsequent apoptotic protein expressions.

• Radiation Oncology Journal
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• v.19 no.3
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• pp.230-236
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• 2001

Purpose : To evaluate treatment results in terms of local control, complications and survival after reirraidiation in recurrent cervical cancer following definite radiation therapy. Material and methods : From November 1987 through March 1998, eighteen patients with recurrent cervical cancer following definite radiation therapy were subsequently treated with reirradiation at Keimyung University Dongsan Medical Center. In regard to the initial FIGO stage, one patient was stage la, five were stage IIa, three were IIb, two were IIb and two were IVa. The age range was 37 to 79 years old with median age of 57. The time interval from initial definite radiation therapy to recurrence ranged from 6 to 122 months with a median of 58 months. The recurrent sites were the uterine cervix in seven patients, vagina in ten and pelvic lymph node in one. Reirradiation was peformed with external radiation and intracavitary radiation in twelve patients, external radiation and implantation in four and external radiation alone in two. The range of external radiation dose was $2,100\~5,400\;cGy$ and the range of the total radiation dose was $3,780\~8,550\;cGy$. The follow-up periods ranged from 8 to 20 months with median of 25 following reirradiation. Results : Fourteen of eighteen patients $(78\%)$ had local control just after reirradiation. The two year disease free survival (2YDFS) rate was $53.6\%$. There were statistically significant differences in the 2YDFS according to both recurrent site (2YDFS $28.5\%$ in uterine cervix, $71.4\%$ in vagina, (p=0.03)) and the total dose (2YDFS $71.8\%$ in >6,000 cGy , $25\%$ in $\leq6,000$ cGy, p=0.007). Seven of ten patients who were followed for more than 20 months remain alive and disease free (7/18, $39\%$). Patients treated with external radiation and intracavitary radiation had a higher rate of 2YDFS. Seven patients including 4 patients with no local control experienced local failure in the uterus or vagina and two patients died with distant metastasis. Complications included rectal bleeding in 3 patients, bowel obstruction treated with surgery in two, hematuria in one, radiation cystitis in two, soft tissue swelling in two and vaginal necrosis spontaneously healed in one. There was no statistical difference in complications according to the total dose or the time to recurrence from initial radiation. Conclusion : In patients with recurrence following definite radiation therapy in the uterine cervical cancer, reirradiation may be effective but requires an effort to reduce radiation induced severe complications.

• Tuberculosis and Respiratory Diseases
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• v.62 no.3
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• pp.203-210
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• 2007

Background: The incidence of adenocarcinoma of the lung has been increasing worldwide, and it has been generally been accepted to be relatively unrelated to smoking with a female preponderance. The aim of this study was to examine the gender-related pathological and survival differences in patients with an adenocarcinoma of the lung. Material and Method: A retrospective review of the clinical information of patients diagnosed with an adenocarcinoma of the lung at Kosin Medical Center from January 1999 to September 2005 was performed. The patient's demographics (age, gender), smoking history, stage, serum tumor marker, pathology classification, EGFR mutation, K-ras mutation, treatment methods, and survival time were analyzed. Result: Of the 438 patients, 179 (40.9%) were female. The median age at the diagnosis was 58 years for females and 59 years for males. However, 25.8% of women and only 17.7% of men were under 50 years of age (p=0.02). The distribution of the disease stage was similar in both men and women. The bronchioloalveolar carcinoma component was diagnosed more often in women (11.2%) than in men (5.0%). The overall survival rate was higher in women than in men (p=0.01), and women had a superior therapeutic response to a combined treatment of surgery and chemotherapy. Conclusion: This study showed significant genders differences in terms of the smoking history, bronchioloalveolar carcinoma component, overall survival, and survival after combined treatment of surgery and chemotherapy. Therefore, gender differences should be considered when diagnosing and treating adenocarcinomas of the lung.

• Radiation Oncology Journal
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• v.26 no.3
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• pp.181-188
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• 2008

Purpose: In order to enhance the efficiency of respiratory gated 4-dimensional radiation therapy for more regular and stable respiratory period and amplitude, a respiration training system was designed, and its efficacy was evaluated. Materials and Methods: The experiment was designed to measure the difference in respiration regularity following the use of a training system. A total of 11 subjects (9 volunteers and 2 patients) were included in the experiments. Three different breathing signals, including free breathing (free-breathing), guided breathing that followed training software (guided-breathing), and free breathing after the guided-breathing (post guided-breathing), were consecutively recorded in each subject. The peak-to-peak (PTP) period of the breathing signal, standard deviation (SD), peak-amplitude and its SD, area of the one cycle of the breathing wave form, and its root mean square (RMS) were measured and computed. Results: The temporal regularity was significantly improved in guided-breathing since the SD of breathing period reduced (free-breathing 0.568 vs guided-breathing 0.344, p=0.0013). The SD of the breathing period representing the post guided-breathing was also reduced, but the difference was not statistically significant (free-breathing 0.568 vs. guided-breathing 0.512, p=ns). Also the SD of measured amplitude was reduced in guided-breathing (free-breathing 1.317 vs. guided-breathing 1.068, p=0.187), although not significant. This indicated that the tidal volume for each breath was kept more even in guided-breathing compared to free-breathing. There was no change in breathing pattern between free-breathing and guided-breathing. The average area of breathing wave form and its RMS in postguided-breathing, however, was reduced by 7% and 5.9%, respectively. Conclusion: The guided-breathing was more stable and regular than the other forms of breathing data. Therefore, the developed respiratory training system was effective in improving the temporal regularity and maintaining a more even tidal volume.

• Journal of Radiation Protection and Research
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• v.27 no.3
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• pp.147-154
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• 2002

Purpose : Measurement of transmission dose is useful for in vivo dosimetry of QA purpose. The objective of this study is to develope an algorithm for estimation of tumor dose using measured transmission dose for open radiation field. Materials and Methods : Transmission dose was measured with various field size (FS), phantom thickness (Tp), and phantom chamber distance (PCD) with a acrylic phantom for 6 MV and 10 MV X-ray. Source to chamber distance (SCD) was set to 150 cm. Measurement was conducted with a 0.6 co Farmer type ion chamber. Using measured data and regression analysis, an algorithm was developed lot estimation of expected reading of transmission dose. Accuracy of the algorithm was tested with flat solid phantom with various settings. Results : The algorithm consisted of quadratic function of log(A/P) (where A/P is area-perimeter ratio) and tertiary function of PCD. The algorithm could estimate dose with very high accuracy for open square field, with errors within ${\pm}0.5%$. For elongated radiation field, the errors were limited to ${\pm}1.0%$. Conclusion : The developed algorithm can accurately estimate the transmission dose in open radiation fields with various treatment settings.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.2
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• pp.83-87
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• 2011

Purpose: Recently in diagnostics area PET/CT is using a variety of areas including oncology, as well as in cardiology, neurology, etc. While increasing in the importance of PET/CT, there are various researches in the image quality related to reconstruction method. We compared and tested Iterative 2D Reconstruction Method with True X Reconstruction method by Siemens through phantom experiment, so we can see increasing of clinical usefulness of PET/CT. Materials and Methods: We measured contrast ratio and FWHM due to evaluating images on dose and experiment using Biograph 40 True Point PET/CT (Siemens, Germany). Getting a result of contrast ratio and FWHM, we used NEMA IEC PET body phantom (Data Spectrum Corp.) and capillary tube. We used the current TrueX and the previous Iterative 2D algorithm for all images which have 10 minutes long. Also, a clinical suitability of parameter for Iterative 2D and a recommended parameter by Siemens for True X are applied to the experiment. Results: We tested FWHM using capillary tube. As a result, TrueX was less than Iterative 2D. Also, the differences of FWHM get bigger in low dose. On the other hand, we tested contrasts ratio using NEMA IEC PET body phantom. As a result, TrueX was better aspect than Iterative 2D. However, there was no difference in dose. Conclusion: In this experiment, TrueX get higher results of contrast ratio and spatial resolution than Itertive 2D through experiment. Also, in the reconstruction result through TrueX, TrueX had better aspect of resolution than Iterative 2D in low dose. However, contrast ratio had no specific difference. In other words, TrueX reconstruction method in PET/CT had higher clinical value in use because TrueX can reduce exposure of patient and had a better quality of screen.

• Radiation Oncology Journal
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• v.16 no.3
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• pp.233-243
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• 1998

Purpose : To evaluate the effects of X-irradiation on prenatal deaths, i.e., preimplantation deaths, embryonic deaths and fetal deaths, and on external malformations in precompacted preimplantation ddy mice Materials and Methods : Pregnant mice (n=85) obtained by limiting the mating time to from 6 to 9 A.M., were segregated into 11 groups. The first five groups (n=26) were irradiated with X-ray doses of 0.1 0.5, 0.75, 1.5, and 3 Gy, respectively, at 24 h post conception (p.c.) of the preimplantation Period. The second five (n=27) groups were irradiated at the same X-ray doses, respectively, but at 48 h p.c. of the preimplantation period. The last group (n=32) was the control group. The uterine contents were examined on the 18th day of gestation for prenatal deaths and external malformations. Results : 1) A statistically significant increase in preimplantation deaths with increasing dose was observed in the experimental groups irradiated at 24 h p.c. and in the groups irradiated at 48 h p.c., as compared to the control group. The threshold dose was close to 0.05 Gy and 0.075 Gy for the irradiations at 24 h p.c. and 48 h p.c. respectively. 2) A statistically significant increase in embryonic deaths with increasing dose was observed in all irradiation groups, except the group irradiated with a dose of 0.1 Gy at 48 h p.c.. 3) No fetal deaths were found in any experimental group. 4) In the experimental groups irradiated at 24 h p.c. anomalies increased with statistical significance, as compared with the control group : 2 exencephalies, 2 open eyelids, 3 anophthalmias, 2 cleft Palates, 2 gastroschisis, 1 abdominal wall defect. 1 leg defect, and 2 short tail anomalies: the threshold dose for external malformations was close to 0.2 Gy at 24 h p.c.. In the groups irradiated at 48 h p.c., 1 open eyelid and 2 short tail anomalies were observed, but there was no statistical significance in those malformations. Conclusion : The results of this study reveal that X-irradiation of precompacted preimplantation ddy mice causes not only preimplantation deaths and embryonic deaths but also external malformations. In addition, external malformations were observed in our experiments at diagnostic doses, including 0.1 and 0.5 Gy. For this reason, we recommend that irradiation should be avoided during the preimplantation period by applying Rugh's 10-day rule.

• Tuberculosis and Respiratory Diseases
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• v.40 no.6
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• pp.700-708
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• 1993

Background: Lung cancer has become one of the most common cancers in Korea. It is important to determine the accurate histologic types and stages because of different therapeutic modlaity, especially in small cell carcinoma. This study was designed to evaluate diagnostic yields according to variable diagnostic methods in lung cancer. Methods: The records of 683 patients with a confirmed diagnosis of primary lung cancer during the period of 7 years, from January, 1986 until December, 1992 at Presbyterian Medical Center were analyzed retrospectively. Results: 1) Age and sex distributions Male: female sex ratio was 5.57:1 and age distributions were 7th decade 41.4%, 6th decade 30.2%, 8th decade 17.0%, 5th decade 7.9%, 4th decade 2.5%, 9th decade 1.3%, and 3rd decade 0.2% in decreasing order. 2) The frequencies according to histologic cell types were squamous cell carcinoma 44.7%, small cell carcinoma 23.9%, adenocarcinoma 22.8%, alveolar cell carcinoma 2.5%, large cell carcinoma 1.2%. mixed forms 1.2%, undifferenciated cell carcinoma 0.6% and malignant fibrous histiocytoma 0.2%(1 case) in decreasing order. 3) The most common locations of lung cancer were in left upper lobe and right lower lobe, and no differences of diagnostic methods according to locations were noted. 4) In central lesions, bronchoscopic examination was very accurate and frequently used diagnostic method, and in peripheral lesions, transthoracic lung biopsy(TTLB) was apparent1y accurate method. 5) The diagnostic yields of bronchoscopic biopsy, bronchial brushing, sputum cytology, transthoracic lung biopsy and transbronchial lung biopsy(TBLB) were 81.3%, 57.5%, 31.1%, 69.6% and 61.6%, respectively. 6) The concordance rates between the histologic diagnosis with bronchial brushing and sputum-cytology were 91.3% and 98.4%, respectively. 7) It was appropriate in lung cancer to repeat sputum cytology 3 to 5 times. Conclusion: Bronchoscopic examination is important to determine the histologic cell types in lung cancer. In addition, we should be interrested in improving diagnostic yields of sputum cytology as an easy method.

• Tuberculosis and Respiratory Diseases
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• v.41 no.4
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• pp.339-353
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• 1994

Background : The p53 gene codes for a DNA-binding nuclear phosphoprotein that appears to inhibit the progression of cells from the G1 to the S phase of the cell cycle. Mutations of the p53 gene are common in a wide variety of human cancers, including lung cancer. In lung cancers, point mutations of the p53 gene have been found in all histological types including approximately 45% of resected NSCLC and even more frequently in SCLC specimens. Mutant forms of the p53 protein have transforming activity and interfere with the cell-cycle regulatory function of the wild-type protein. The majority of p53 gene mutations produce proteins with altered conformation and prolonged half life; these mutant proteins accumulate in the cell nucleus and can be detected by immunohistochemical staining. But protein overexpression has been reported in the absence of mutation. p53 protein overexpression or gene mutation is reported poor prognostic factor in breast cancer, but in lung cancer, its prognostic significance is controversial. Method : We investigated the p53 abnormalities by nucleotide sequencing, polymerase chain reaction-single strand conformation polymorphism(PCR-SSCP), and immunohistochemical staining. We correlated these results with each other and survival in 75 patients with NSCLC resected with curative intent. Overexpression of the p53 protein was studied immunohistochemically in archival paraffin- embedded tumor samples using the D07(Novocastra, U.K.) antibody. Overexpression of p53 protein was defined by the nuclear staining of greater than 25% immunopositive cells in tumors. Detection of p53 gene mutation was done by PCR-SSCP and nucleotide sequencing from the exon 5-9 of p53 gene. Result: 1) Of the 75 patients, 36%(27/75) showed p53 overexpression by immunohistochemical stain. There was no survival difference between positive and negative p53 immunostaining(overall median survival of 26 months, disease free median survival of 13 months in both groups). 2) By PCR-SSCP, 27.6%(16/58) of the patients showed mobility shift. There was no significant difference in survival according to mobility shift(overall median survival of 27 in patients without mobility shift vs 20 months in patients with mobility shift, disease free median survival of 8 months vs 10 months respectively). 3) Nucleotide sequence was analysed from 29 patients, and 34.5%(10/29) had mutant p53 sequence. Patients with the presence of gene mutations showed tendency to shortened survival compared with the patients with no mutation(overall median survival of 22 vs 27 months, disease free median survival of 10 vs 20 months), but there was no statistical significance. 4) The sensitivity and specificity of immunostain based on PCR-SSCP was 67.0%, 74.0%, and that of the PCR-SSCP based on the nucleotide sequencing was 91.8%, 96.2% respectively. The concordance rate between the immunostain and PCR-SSCP was 62.5%, and the rate between the PCR-SSCP and nucleotide sequencing was 95.3%. Conclusion : In terms of detection of p53 gene mutation, PCR-SSCP was superior to immunostaining. p53 gene abnormalities either overexpression or mutation were not a significant prognostic factor in NSCLC patients resected with curative intent. However, patients with the mutated p53 gene showed the trends of early relapse.