• The Journal of Korean Society for Radiation Therapy
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• v.14 no.1
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• pp.35-39
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• 2002

Introduction : It is essential to input patients external contour in 3D treatment plan. We would like to see changes in depth and dose when 3D RTP is operating auto contouring when windows value (Width/Level) differs in this process. Material & Methode : We have analyzed the results with 3D RTP after CT Scanning with round CT Phantom. We have compared and analyzed MU values according to depth changes to Isocenter changing external contour and inputting random Window value. We have watched change values according to dose optimization in 4 directions(LAO, LPO, RAO, RPO), We plan 100 case for exact analyzation. We have results changing window value random to each beam in 100 cans. Result : It showed change between minimum and maximum value in 4 beam is Depth 0.26mm, MU $1.2\%$ in LAO. It showed LPO-Depth 0.13mm, MU $0.9\%$, RAO-Depth 0.2mm MU $0.8\%$, RPO-Depth 0.27mm, MU $1.1\%$ Conclusion : Maximum change in depth 0.27 mm, MU error rate is $0.12\%$ according to Window change. As we can see in these results, it seems Window value change doesn't effect in treatment. However, it seems there needs to select appropriate Window value in precise treatment.

• Radiation Oncology Journal
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• v.13 no.1
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• pp.27-31
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• 1995

Purpose : This study was done to evaluate preliminarily the role of intraluminal brachytherapy in the radiation treatment of non-metastatic esophageal cancer, Materials and Methods: We analyzed follow-up result of 21 patients treated at the dept. of therapeutic radiology in Gyeongsang national university hospital between April, 1989 and August, 1992. All patients received neoadjuvant chemotherapy(5-FU, Cispl-atin). Fifteen Patients were treated with external beam alone, and in remaining 6 patients, the external beam radiotherapy followed by intraluminal brachytherapy was done. Results : Among 21 patients, 7 patients showed complete tumor regression after completion of radiotherapy. But 2 of these complete responder recurred at the site of primary disease, so ultimate local control rate was $23.8\%$(5/21). Local control rate according to radiation treatment modality was $6.7\%$(1/15) in patients treaed with external irradiation only, and $66.7\%$ in patients treated with combined external irradiation and intraluminal brachytherapy. The 2 year NED survival rate was $6.6.\%$ in the former and $66.7\%$ in the latter. Conclusion: Although there should be consideration about case selection for addition of intraluminal brachytherapy intraluminal brachytherapy may be considerded as one of the method to enhance the local control probability of esophageal cancer.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.477-483
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• 1998

Purpose : Radiation proctitis and radiation cystitis are frequent and problematic late complications in patients treated with radiation for the uterine cervix cancer. Authors tried to find out the better patient's position in high dose rate intracavitary radiation to reduce the radiation dose of bladder and rectum. Materials and Methods : In 13 patients, Foley Catheters were inserted to patient's bladder and rectum and were ballooned with radioopaque dye. After insertion of a tandem and two ovoids, semi-orthogonal anteroposterior and lateral films were taken in both lithotomy and supine position. The rectal point and bladder point were defined according to the criteria recommended in the ICRU Report 38 with modification. Using these films, all patients' bladder and rectal dose were calculated in both positions (the radiation dose of A point was set to 400 cGy). And also, the distance of bladder and rectum from uterine cervical os was calculated in both positions. Results : The average radiation dose of rectum was 240.7 cGy in lithotomy position and 278.3 cGy in supine position, and the average radiation dose of bladder was 303.5 cGy in lithotomy position and 255.8 cGy in supine position. After the paired t-test, the radiation dose of rectum in lithotomy position was marginally significantly lower than that in supine position, while the radiation dose of bladder in lithotomy position was significantly higher than that in supine position. On the other hand, the average distance between rectum and cervical os was 35.2 mm in lithotomy position and 32.3 mm in supine position. and the average distance between bladder and cervical os was 30.4 mm in lithotomy position and 34.0 mm in supine position. After the paired t-test. the distance between rectum and cervical os in lithotomy position was significantly longer than that in supine position, while the distance between bladder and cervical os in lithotomy position was significantly shorter than that in supine position. Conclusion : The radiation dose of bladder can be reduced in supine position and the radiation dose of rectum can be reduced in lithotomy position, so we can choose appropriate position in each patient.

• 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.

• Korean Journal of Bronchoesophagology
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• v.15 no.2
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• pp.49-56
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• 2009

Purpose : To evaluate the treatment outcome for patients with locally advanced, unresectable esophageal cancer treated with relatively high dose radiation therapy(RT). Materials and Methods : From January 2000 to December 2008, 32 patients with locally advanced unresectable or medically inoperable esophageal cancer were treated with radiation therapy(RT) with or without concurrent chemotherapy. Ten patients were excluded from analysis because of distant metastasis and drop off. Patient distributions according to AJCC stages II, III IVa were 7(31.8%), 12(54.6%), 3(13.6%) respectively. The locations of tumor were cervical/upper thorax 3 (13.6%), mid thorax 13(59.1%), and lower thorax/abdominal 6(27.3%), respectively. Eleven patients received RT only, and 11 patients received cisplatin based concurrent chemoradiotherapy(CCRT). Median radiation dose was 65 Gy(range 57.6~72 Gy). Results : The median follow-up was 9.1 months(range 1.9~43.8 months). The response rates for complete response, Partial response, stable disease and Persistent disease were 6(27.3%), 11(50.0%), 4(18.2%) and 1(4.5%), respectively. Two patients(9.1%) suffered from esophageal stenosis and stents were inserted. Two patients(9.1%) had Grade 3 radiation pneumonitis and one of them expired due to acute respiratory distress syndrome(ARDS) at 36 days after completion of radiation therapy. The recurrence rate was 11(50.0%). The patterns of recurrence were persistent disease and local progression in 5(22.7%), local recurrence 3(13.7%) and concomitant local and distant recurrence in 3(13.7%). The overall survival(OS) rate was 32.1% at 2 years and 21.4% at 3 years(median 12.0 months). Disease free survival(DFS) rate was 17.3% at 2 and 3 years. All patients who had no dysphagia at diagnosis showed complete response after treatment and 100% OS at 3 years(p=0.0041). The OS for above 64.8 Gy group and 64.8 Gy or below group at 3 years were 60.6% and 9.1%(p=0.1341). The response to treatment was the only significant factor affecting OS(p=0.004). Conclusion : Relatively high dose radiation therapy in unresectable esophageal cancer tended to have a better outcome without increased complication rate. Further study with more patients is warranted to justify improved result.

• Radiation Oncology Journal
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• v.12 no.3
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• pp.369-376
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• 1994

This is a retrospective analysis of 64 patients who was treated with postoperative radiation therapy after radical hysterectomy and bilateral pelvic lymphadenectomy (53 patients) or total abdominal hysterectomy(11 patients) for uterine cervix cancer between May 1980 and September 1991 at the Department of Radiation Oncology, Kyung Hee University Hospital. Most patients were FIGO IB (31 Patients) and IIA (25 patients), and median period of follow-up was 5.1 years. Of these patients,24 received adjuvant whole pelvis irradiation of 6000 cGy and 40 received 5000-5500 cGy whole pelvis irradiation and/or intracavitary radiation (7 Patients). The actuarial overall and relapse free 5 year survival rate were $71.0\%$, $68.3\%$ respectively. The survival rates by stage were $79.1\%$ in stage I, and $61.2\%$ in stage II. Treatment failure was noted in 18 of 64 patients ($28.1\%$), Iocoregional failure in 8 ($12.5\%$), distant metastasis in 8 ($12.5\%$), paraaortic node metastasis in 1 and one patient and concurrent locoregional and distant metastasis. The univariate analysis of prognostic factors affecting to overall survival rate represented lymph node status, the number and site of metastatic lymph node, parametrial invasion, the thichness of cervical wall invasion, and size of cancer mass. Histology, vessel invasion, endometrial extension, hemoglobin level. resection margin status, age, radiation dose were not significant prognostic factors. Complication relating to operation and postoperative radiation were variable according to radiation therapy method: 6000 cGy RT group 8/24($33.3\%$), 5000-5500 cGy+ICR 3/7 ($42.9\%$), 5000-5500 cGy external RT only group 3/33 ($9.1\%$). In conclusion, the results suggest that postoperative radiotherapy is necessary in high risk patients for locoregional control and improving survival rate, and higher dose does not improve results but only increases complication.

• Journal of Radiation Protection and Research
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• v.44 no.2
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• pp.79-88
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• 2019

Background: The main goal of experiments is to compare various operational and technical characteristics of D-Shuttle semiconductor personal dosimeters of the Japanese company "Chiyoda Technol Corporation" and Harshaw thermoluminescent dosimeters (TLD) manufactured by "Thermo Fisher Scientific" and DTL-02 of the Russian Research and Production Enterprise (RPE) "Doza" by their occupational and calibration exposure at various dose equivalents from 0.5 to 20 mSv of gamma-radiation. Materials and Methods: Besides dosimeters DTL-02, D-Shuttle and Harshaw TLD, there were also used: (1) the primary reference radionuclide source Hopewell Designs IAEA: G10-1-12 with $^{137}Cs$ isotope (an error is not more than 6% and activity is 20 Ci), and (2) the verification device UPGD-2M of RPE "Doza" and installed in the National Center for Expertise and Certification of the Republic of Kazakhstan (Kapchagai, the National Center for Expertise and Certification). Results and Discussion: The main results of researches are the following: (1) TLDs for Harshaw 6600 and DVG-02TM have an approximately equal measurement accuracy of the individual dose equivalents in the range from 0.5 to 20 mSv of gamma-radiation. (2) Advantages of dosimeters for Harshaw 6600 are due to the high measurement productivity and opportunity to indicate the dose on the skin $H_p$(0.07). Advantages of DVG-02TM consist of operation simplicity and lower cost than of Harshaw 6600. (3) D-Shuttles are convenient for use in the current and the operational monitoring of ionizing radiation. Measurement accuracy and 10% linearity of measurements are ensured when D-Shuttle is irradiated with dose equivalents below 1 mSv at the equivalent dose rate not higher than $3mSv{\cdot}hr^{-1}$. This allows using D-Shuttle at a routine technological activity. Conclusion: The obtained results of experiments demonstrate advantages and disadvantages of D-Shuttle semiconductor dosimeters in comparison with two TLD systems of DVG-02TM and Harshaw 6600.

• Journal of Radiation Protection and Research
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• v.31 no.2
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• pp.69-89
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• 2006

Biological mechanisms for ionizing radiation effects are different at low doses than at high doses. Radiation hormesis involves low-dose-induced protection and high-dose-induced harm. The protective component is associated with a reduction in the incidence of cancer below the spontaneous frequency, brought about by activation of defensive and repair processes. The Linear No-Threshold (LNT) hypothesis advocated by the International Commission on Radiological Protection (ICRP) and the Biological Effects of ionizing Radiation (BEIR) Report VII for cancer risk estimations Ignores hormesis and the presence of a threshold. Cancer incidences significantly less than expected have been found in a large number of epidemiological studies including, airline flight personnel, inhabitants of high radiation backgrounds, shipyard workers, nuclear site workers in scores of locations throughout the world, nuclear power utility workers, plutonium workers, military nuclear test site Participants, Japanese A-bomb survivors, residents contaminated by major nuclear accidents, residents of Taiwan living in $^{60}Co$ contaminated buildings, fluoroscopy and mammography patients, radium dial painters, and those exposed to indoor radon. Significantly increased cancer was not found at doses <200 $mSv^*$. Evidence for radiation hormesis was seen in both sexes for acute or chronic exposures, low or high LET radiations, external whole- or partial body exposures, and for internal radionuclides. The ubiquitous nature of the Healthy Worker Effect (HWE)-like responses in cellular, animal and epidemiological studies negates the HWE as an explanation for radiation hormesis. The LNT hypothesis is wrong and does not represent the true nature of the dose-response relationship, since low doses or dose-rates commonly result in thresholds and reduce cancer incidences below the spontaneous rate. Radiation protection organizations should seriously consider the cost and health implications of radiation hormesis.

• Journal of Radiation Protection and Research
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• v.23 no.4
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• pp.211-218
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• 1998

The distributional effects of radioactive materials on external gamma exposure have been analyzed. An approximate method for estimating external gamma dose given from an arbitrary distribution of radioactive material has been developed. The minimum gamma exposure given from a point source is shown at 0.07 MeV if the source to receptor distance is shorter than 10 m. But if the receptor to point source distance is longer than 20 m, gamma exposure rate increases monotonously according to the average gamma energy. For the analysis of the effects of volume source, we estimated the gamma dose given from different size of hemisphere in which radioactive materials are distributed uniformly. When the radius of hemisphere is longer than 40 m, external gamma dose rate increases monotonously. The gamma dose rate given from the radioactive materials deposited on the ground shows the minimum value at 0.07 MeV in any case. The analysis shows that external gamma exposure is strongly dependent on the distribution of radioactive materials in the environment and gamma energy.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1757-1762
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• 2023

Radiological hazards from external exposure of naturally occurring radioactive materials (NORM) scales residues, generated during the extraction process of oil and gas production in southern Algeria, are evaluated. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K were measured using high-purity gamma-ray spectrometry (GeHP). Mean activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K, found in scale samples are 4082 ± 41, 1060 ± 38 and 568 ± 36 Bq kg^-1, respectively. Radiological hazard parameters, such as radium equivalent (Ra_eq), external and internal hazard indices (H_ex, H_in), and gamma index (I_γ) are also evaluated. All hazard parameter values were greater than the permissible and recommended limits and the average annual effective dose value exceeded the dose constraint (0.3 mSv y^-1). However, for occasionally exposed workers, the dose rate of 0.65 ± 0.02 mSv y^-1 is lower than recommended limit of 1 mSv y^-1 for public.