• Radiation Oncology Journal
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• v.17 no.3
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• pp.217-222
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• 1999

Purpose : To evaluate prognostic factors and survival rates of the patients who received radiation therapy for locally recurrent uterine cervical cancer after curative surgery. Materials and Methods : Between October 1983 and July 1990, fifty three patients who received radiation therapy for locally recurrent cervical cancer after curative surgery at the Department of Therapeutic Radiology, Kangnam St. Mary's Hospital, The Catholic University of Korea were analysed retrospectively. Age at diagnosis ranged from 33 to 69 years (median 53 years). Pathological analysis showed that forty five ($84.9\%$) patients had squamous cell carcinoma, seven ($13.2\%$) patients had adenocarcinoma, and one (1.9%) patient had adenosquamous cell carcinoma. The interval between hysterectomy and tumor recurrence ranged from 2 months to 25 years (mean 34.4 months). The recurrent sites were vaginal stump in 41 patients ($77.4\%$) and pelvic side wall in 12 patients ($22.6\%$). Recurrent tumor size was devided into two groups : less than 3 cm in 43 patients ($81.1\%$) and more than 3 cm in 10 patients ($18.9\%$). External beam irradiation of whole pelvis was done first up to 46.8 Gy to 50.4 Gy in 5 weeks to 6 weeks, followed by either external beam boost to the recurrent site in 18 patients ($34\%$) or intracavitary irradiation in 24 patients ($45.3\%$). Total dose of radiation ranged from 46.8 Gy to 111 Gy (median 70.2 Gy). Follow up period ranged from 2 to 153 months with a median of 35 months. Results : Overall response rate was $66\%$ (35/53). Among them, six patients ($17.1\%$) relapsed between 7 months and 116 months after radiation therapy (mean 47.7 months), Therefore overall recurrence rate was $45.3\%$. Overall five-year actuarial survival rate was $78.9\%$ and distant failure rate was $10\%$ (5/50). The significant prognostic factors affecting survival rate were interval between primary surgery and tumor recurrence (p=0.0055), recurrent tumor size (p=0.0039), and initial response to radiation therapy (p=0.0428). Complications were observed in 10 ($20/%$) patients, which included mild to moderate lower gastrointestinal, genitourinary, or skin manifestations. One patient died of pulmonary embolism just after intracavitary irradiation. Conclustion : Radiation therapy is the effective treatment for the patients with locally recurrent cervical cancer after curative surgery. These results suggest that interval between primary surgery and tumor recurrence, recurrent tumor size, and initial response to radiation therapy were significant prognostic factors for recurrent cervical cancer.

• Radiation Oncology Journal
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• v.16 no.3
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• pp.265-274
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• 1998

Purpose : This prospective study has been conducted to assess the value of three dimensional conformal radiation therapy (3DCRT) for lung cancer and to determine its potential advantage over current treatment approaches. Specific aims of this study were to 1) find the most ideal 3DCRT technique 2) establish the maximum tolerance dose that can be delivered with 3DCRT and 3) identify patients at risk for development of radiation pneumonitis. Materials and Methods : Beginning in Nov. 1994, 95 patients with inoperable non-small cell lung cancer (stage I; 4, stage II; 1, stage IIIa; 14, stage IIIb; 76) were entered onto this 3D conformal trial Areas of known disease and elective nodal areas were initially treated to 45 Gy and then using 3DCRT technique 65 to 70 Gy of total dose were delivered to the gross disease. Sixty nine patients received 65 Gy of total dose and 26 received 70 Gy Seventy eight patients (82.1$\%$) also received concurrent MVP chemotherapy. 3DCRT plans were compared with 2D plans to assess the adequacy of dose delivery to target volume, dose volume histograms for normal tissue, and normal tissue complication Probabilities (NTCP). Results : Most of plans (78/95) were composed of non-coplanar multiple (4-8) fields. Coplanar segmented conformal therapy was used in 17 pateints, choosing the proper gantry angle which minimize normal lung exposure in each segment. 3DCRT gave the full dose to nearly 100$\%$ of the gross disease target volume in all patients. The mean NTCP for ipsilateral lung with 3DCRT (range; 0.17-0.43) was 68$\%$ of the mean NTCP with 2D treatment planning (range; 0.27-0.66). DVH analysis for heart showed that irradiated volume of heart could be significantly reduced by non-coplanar 3D approach especially in the case of left lower lobe lesion. Of 95 patients evaluable for response, 75 (79$\%$), showed major response including 25 (26$\%$) with complete responses and 50 (53$\%$) with partial responses. One and two rear overall survivals of stage III patients were 62.6$\%$ and 35.2$\%$ respectively. Twenty percent (19/95) of patients had pneumonitis; Eight patients had grade 1 pneumonitis and 11 other patients had grade 2. Comparison of the average of NTCP for lung showed a significant difference between patients with and without radiation pneumonitis. Average NTCP for Patients without complication was 62$\%$ of those with complications. Conclusions : This study showed that non-coplanar multiple fields (4-8) may be one of the ideal plans for 3DCRT for lung cancer. It also suggested that 3DCRT may provide superior delivery of high dose radiation with reduced risk to normal tissue and that NTCP can be used as a guideline for the dose escalation.

• The Journal of Korean Society for Radiation Therapy
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• v.21 no.1
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• pp.9-15
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• 2009

Purpose: We evaluated the device that was created for maintaining the patient's setup and protecting the testicles from scattered radiation during treatment of carcinoma of the penis. Materials and Methods: The phantom testicles were made of vaseline cotton gauze and the device consisted of 5 mm of acryl box and 4 mm of lead shielding. $3{\times}3\;cm^2$, $4{\times}4\;cm^2$, $5{\times}5\;cm^2$, $6{\times}6\;cm^2$, $7{\times}7\;cm^2$ field sizes were used for this study and measurement was made at 4, 5, 6, 7, 8, 10 cm from the lower edge of the field for 10 times with lead shielding and without the shielding respectively. 200 cGy was delivered using 6 MV photons. Results: The scatted radiation without lead shielding at 4, 5, 6, 7, 8, 10 cm from the lower edge of the field were 14.8-4.7 cGy with $3{\times}3\;cm^2$, 15.7-5.2 cGy with $4{\times}4\;cm^2$, 17.6-5.5 cGy with $5{\times}5\;cm^2$, 19.9-6.6 cGy with $6{\times}6\;cm^2$, 22.2-7.6 cGy with $7{\times}7\;cm^2$ and the measured dose without lead shielding were 7.1-2.6 cGy with $3{\times}3\;cm^2$, 8.9-3.6 cGy with $4{\times}4\;cm^2$, 12.3-4.8 cGy with $5{\times}5\;cm^2$, 14.6-5.0 cGy with $6{\times}6\;cm^2$ and 21.1~6.4 cGy with $7{\times}7\;cm^2$. As shown above, the scatted radiation decreased after using lead shielding. Depending of the range of field sizes, the resulting difference between without shielding values and with shielding values were: 7.8-1.1 cGy at 4 cm, 5.1-1.2 cGy at 5 cm, 3.8-1.1 cGy at 6 cm, 3.4-1.7 cGy at 7 cm, 2.8-1.7 cGy at 8 cm, 2.4-2.5 cGy at 9 cm and 2.1-1.8 cGy at 10 cm. In the situation as described above, the range in values depending on the distance was 7.8-1.1 cGy with $3{\times}3\;cm^2$, 6.9-1.6 cGy with $4{\times}4\;cm^2$, 5.3-0.8 cGy with $5{\times}5\;cm^2$, 5.3-1.5 cGy with $6{\times}6\;cm^2$ and 1.1-1.8 cGy with $7{\times}7\;cm^2$. Conclusion: Using the device we created to shield the testicles from scattered radiation during treatment of carcinoma of the penis, we have found that scattered radiation to the testicles is decreased by the phantom testicles, and by increasing the distance between the testicles and penis.

• The Korean Journal of Nuclear Medicine
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• v.37 no.4
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• pp.219-228
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• 2003

Purpose: The amount of salvaged myocardium is an important prognostic factor in patients with acute myocardial infarction (MI). We investigated if early Tl-201 SPECT imaging could be used to predict the salvaged myocardium and functional recovery in acute MI after primary PTCA. Materials and Methods: In 36 patients with first acute MI treated with primary PTCA, serial echocardiography and Tl-201 SPECT imaging ($5.8{\pm}2.1$ days after PTDA) were performed. Regional wall motion and perfusion were quantified with on 16-segment myocardial model with 5-point and 4-point scaling system, respectively. Results: Wall motion was improved in 78 of the 212 dyssynergic segments on 1 month follow-up echocardiography and 97 on 7 months follow-up echocardiography, which were proved to be salvaged myocardium. The areas under receiver operating characteristic curves of Tl-201 perfusion score for detecting salvaged myocardial segments were 0.79 for 1 month follow-up and 0.83 for 7 months follow-up. The sensitivity and specificity of Tl-201 redistribution images with optimum cutoff of 40% of peak thallium activity for detecting salvaged myocardium were 84.6% and 55.2% for 1 month follow-up, and 87.6% and 64.3% for 7 months follow-up, respectively. There was a linear relationship between the percentage of peak thallium activity on early redistribution imaging and the likelihood of segmental functional improvement 7 months after reperfusion. Conclusion: Tl-201 myocardial perfusion SPECT imaging performed early within 10 days after reperfusion can be used to predict the salvaged myocardium and functional recovery with high sensitivity during the 7 months following primary PTCA in patients with acute MI.

• Radiation Oncology Journal
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• v.19 no.3
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• pp.275-286
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• 2001

Purpose : To setup procedures of quality assurance (OA) for implementing intensity modulated radiation therapy (IMRT) clinically, report OA procedures peformed for one patient with prostate cancer. Materials and methods : $P^3IMRT$ (ADAC) and linear accelerator (Siemens) with multileaf collimator are used to implement IMRT. At first, the positional accuracy, reproducibility of MLC, and leaf transmission factor were evaluated. RTP commissioning was peformed again to consider small field effect. After RTP recommissioning, a test plan of a C-shaped PTV was made using 9 intensity modulated beams, and the calculated isocenter dose was compared with the measured one in solid water phantom. As a patient-specific IMRT QA, one patient with prostate cancer was planned using 6 beams of total 74 segmented fields. The same beams were used to recalculate dose in a solid water phantom. Dose of these beams were measured with a 0.015 cc micro-ionization chamber, a diode detector, films, and an array detector and compared with calculated one. Results : The positioning accuracy of MLC was about 1 mm, and the reproducibility was around 0.5 mm. For leaf transmission factor for 10 MV photon beams, interleaf leakage was measured $1.9\%$ and midleaf leakage $0.9\%$ relative to $10\times\;cm^2$ open filed. Penumbra measured with film, diode detector, microionization chamber, and conventional 0.125 cc chamber showed that $80\~20\%$ penumbra width measured with a 0.125 cc chamber was 2 mm larger than that of film, which means a 0.125 cc ionization chamber was unacceptable for measuring small field such like 0.5 cm beamlet. After RTP recommissioning, the discrepancy between the measured and calculated dose profile for a small field of $1\times1\;cm^2$ size was less than $2\%$. The isocenter dose of the test plan of C-shaped PTV was measured two times with micro-ionization chamber in solid phantom showed that the errors upto $12\%$ for individual beam, but total dose delivered were agreed with the calculated within $2\%$. The transverse dose distribution measured with EC-L film was agreed with the calculated one in general. The isocenter dose for the patient measured in solid phantom was agreed within $1.5\%$. On-axis dose profiles of each individual beam at the position of the central leaf measured with film and array detector were found that at out-of-the-field region, the calculated dose underestimates about $2\%$, at inside-the-field the measured one was agreed within $3\%$, except some position. Conclusion : It is necessary more tight quality control of MLC for IMRT relative to conventional large field treatment and to develop QA procedures to check intensity pattern more efficiently. At the conclusion, we did setup an appropriate QA procedures for IMRT by a series of verifications including the measurement of absolute dose at the isocenter with a micro-ionization chamber, film dosimetry for verifying intensity pattern, and another measurement with an array detector for comparing off-axis dose profile.

• The Korean Journal of Nuclear Medicine
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• v.36 no.4
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• pp.244-254
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• 2002

Purpose: This study investigated the differences between technetium-99m ethyl cysteinate dimer (Tc-99m ECD) and technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) uptake in the normal brain by means of statistical parametric mapping (SPM) analysis. Materials and Methods: We retrospectively analyzed age and sex matched 53 cases of normal brain SPECT. Thirty-two cases were obtained with Tc-99m ECD and 21 cases with Tc-99m HMPAO. There were no abnormal findings on brain MRIs. All of the SPECT images were spatially transformed to standard space, smoothed and globally normalized. The differences between the Tc-99m ECD and Tc-99m HMPAO SPECT images were statistically analyzed using statistical parametric mapping (SPM'99) software. The differences bgetween the two groups were considered significant ant a threshold of corrected P values less than 0.05. Results: SPM analysis revealed significantly different uptakes of Tc-99m ECD and Tc-99m HMPAO in the normal brains. On the Tc-99m ECD SPECT images, relatively higher uptake was observed in the frontal, parietal and occipital lobes, in the basal ganglia and thalamus, and in the superior region of the cerebellum. On the Tc-99m HMPAO SPECT images, relatively higher uptakes was observed in subcortical areas of the frontal region, temporal lobe, and posterior portion of inferior cerebellum. Conclusion: Uptake of Tc-99m ECD and Tc-99m HMPO in the normallooking brain was significantly different on SPM analysis. The selective use of Tc-99m ECD of Tc-99m HMPAO in brain SPECT imaging appears especially valuable for the interpretation of cerebral perfusion. Further investigation is necessary to determine which tracer is more accurate for diagnosing different clinical conditions.

• Journal of the Korean Arthroscopy Society
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• v.8 no.2
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• pp.82-88
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• 2004

Purpose: In this study, we intended to ascertain the benefit of KT-2000 Knee arthrometer(KT-2000) in the diagnosis of ACL(Anterior cruciate ligament) injury by comparing the anterior displacement of normal knee with that of ACL deficient knee. Materials and Methods: We designated two examiners to measure the anterior displacement of the knee joint of 30 healthy individuals, using KT-2000, at 30$^{\circ}$ flexion setting of muscle full relaxation, contraction, 25$^{\circ}$ internal rotation and 25$^{\circ}$ external rotation and analyzed these results according to the variables and measured the preoperative anterior displacement of the ACL injured knee in the 30 patients who have gone through an arthroscopic ACL reconstruction later. Results: The results of examiner 1 are 6.5${\pm}$1.5 mm, 2.5${\pm}$0.9 mm, 4.8${\pm}$1.2 mm, 6.4${\pm}$1.3 mm in right knee and 5.6${\pm}$1.3 mm, 2.1${\pm}$0.8 mm, 4.5${\pm}$1.2 mm, 5.2${\pm}$1.3 mm in left knee, in order of muscle full relaxation, contraction, 25$^{\circ}$ internal rotation and 25$^{\circ}$ external rotation. The results of examiner 2 are 6.9${\pm}$1.2mm, 2.9${\pm}$1.1mm, 5.6${\pm}$1.6mm, 6.9${\pm}$1.5mm in right, 5.5${\pm}$1.7 mm,1.9${\pm}$0.9 mm, 5.1${\pm}$1.9 mm, 5.7${\pm}$1.6 mm in left knee, The side to side difference of examiner 1 in the setting of muscle relaxation is 0.9${\pm}$1.0 mm. The anterior displaement of ACL injured knee is average 11${\pm}$2.93 mm and difference of average 6.5${\pm}$2.31 mm form that of normal. In comparison between the right and left knees of healthy individuals, the both results of two examiners showed the statistical difference in the setting of muscle full relaxation but, the results showed the side to side difference below 2 mm in 25case(83%), 21case(70%) respectively and above 3 mm in just 1 case. In the comparison between the normal and ACL injured knees, the results show the statistical difference of the side to side difference in the setting of muscle relaxation(p<0.05). Conclusion: The KT-2000 result is affected by relaxation of muscles around knee, flexion angle of knee joint, rotation of tibia, the strength of displacing force, time of the test and physical factors as height and weight. However, the Accuracy of diagnosis of ACL injury by KT-2000 will increase if the examiner is skillful and the tests are made on the exact position of knee joint.

• The Journal of Korean Society for Radiation Therapy
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• v.32
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• pp.17-29
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• 2020

Purpose: The purpose of this work was to investigate the dosimetric impact of mixed energy partial arc technique on prostate cancer VMAT. Materials and Methods: This study involved prostate only patients planned with 70Gy in 30 fractions to the planning target volume (PTV). Femoral heads, Bladder and Rectum were considered as oragan at risk (OARs). For this study, mixed energy partial arcs (MEPA) were generated with gantry angle set to 180°~230°, 310°~50° for 6MV arc and 130°~50°, 310°~230° for 15MV arc. Each arc set the avoidance sector which is gantry angle 230°~310°, 50°~130° at first arc and 50°~310° at second arc. After that, two plans were summed and were analyzed the dosimetry parameter of each structure such as Maximum dose, Mean dose, D2%, Homogeneity index (HI) and Conformity Index (CI) for PTV and Maximum dose, Mean dose, V70Gy, V50Gy, V30Gy, and V20Gy for OARs and Monitor Unit (MU) with 6MV 1 ARC, 6MV, 10MV, 15MV 2 ARC plan. Results: In MEPA, the maximum dose, mean dose and D2% were lower than 6MV 1 ARC plan(p<0.0005). However, the average difference of maximum dose was 0.24%, 0.39%, 0.60% (p<0.450, 0.321, 0.139) higher than 6MV, 10MV, 15MV 2 ARC plan, respectively and D2% was 0.42%, 0.49%, 0.59% (p<0.073, 0.087, 0.033) higher than compared plans. The average difference of mean dose was 0.09% lower than 10MV 2 ARC plan, but it is 0.27%, 0.12% (p<0.184, 0.521) higher than 6MV 2 ARC, 15MV 2 ARC plan, respectively. HI was 0.064±0.006 which is the lowest value (p<0.005, 0.357, 0.273, 0.801) among the all plans. For CI, there was no significant differences which were 1.12±0.038 in MEPA, 1.12±0.036, 1.11±0.024, 1.11±0.030, 1.12±0.027 in 6MV 1 ARC, 6MV, 10MV, 15MV 2 ARC, respectively. MEPA produced significantly lower rectum dose. Especially, V70Gy, V50Gy, V30Gy, V20Gy were 3.40, 16.79, 37.86, 48.09 that were lower than other plans. For bladder dose, V30Gy, V20Gy were lower than other plans. However, the mean dose of both femoral head were 9.69±2.93, 9.88±2.5 which were 2.8Gy~3.28Gy higher than other plans. The mean MU of MEPA were 19.53% lower than 6MV 1 ARC, 5.7% lower than 10MV 2 ARC respectively. Conclusion: This study for prostate radiotherapy demonstrated that a choice of MEPA VMAT has the potential to minimize doses to OARs and improve homogeneity to PTV at the expense of a moderate increase in maximum and mean dose to the femoral heads.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.8 no.1
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• pp.129-177
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• 1970

For the purpose of establishing the systematized technical scheme of the cooperative rice cultivation which has most significant impact to improve rice productivity and the farm management, the author have studied the cultivation practices, and the variation of rice growth and yield between the cooperative rice cultivation and the individual rice cultivation at random selected 18 paddy fields. The author also have investigated through comparative method on the cultivation practices, management, organization and operation scheme of the two different rice cultivation methods at 460 paddy fields. The economic feasibility has been ana lysed and added in this report. The results obtained from this study are summarized as follows; 1. In the nursery, the average amount of fertilizer application, especially, phosphate and potassium, and the frequency of chemicals spray for the disease, insect and pest control at the cooperative rice cultivation are significantly higher than those of the individual rice cultivation. 2. The cultivation techniques of the cooperative rice farming after the transplanting can be characterized by a) the earlier transplanting of rice, b) the denser hills per unit area and the lesser number of seedlings per hill, c) the application of larger quantities of fertilizer including nitrogen, phosphate and potassium, d) more divided application of fertilizers, split doses of the nitrogen and potassium, e) the increased frequencies of the chemicals spray for the prevention of disease, insect and pest damages. 3. The rate of lodging in the cooperative rice cultivation was slightly higher than that of the individual rice cultivation, however, the losses of rice yield owing to the occurrence of rice stem borer and grass leaf roller in the cooperative rice cultivation were lower than that of the individual rice cultivation. 4. The culm length, panicle length, straw weight and grain-straw ratio are respectively higher at the cooperative rice cultivation, moreover, the higher variation of the above factors due to different localities of the paddy fields found at the individual rice cultivation. 5. The number of panicles, number of flowers per panicle and the weight of 1, 000 grains, those contributing components to the rice yield were significantly greater in the cooperative rice cultivation, however, not clear difference in the maturing rate was observed. The variation coefficient of the yield component in the cooperative cultivation showed lower than that or the individual rice cultivation. 6. The average yield of brown rice per 10 are in the cooperative rice cultivation obtained 459.0 kilograms while that of the individual rice cultivation brought 374.8 kilograms. The yield of brown rice in the cooperative rice cultivation increased 84.2 kilogram per 10 are over the individual rice cultivation. With lower variation coefficient of the brown rice yield in the cooperative rice cultivation, it can be said that uniformed higher yield could be obtained through the cooperative rice cultivation. 7. Highly significant positive correlations shown between the seeding date and the number of flowers per panicle, the chemical spray and the number of flowers per panicle, the transplanting date and the number of flowers per panicle, phosphate application and yield, potassium application and maturing rate, the split application of fertilizers and yield. Whilst the significant negative correlation was shown between the transplanting date and the maturing rate 8. The results of investigation from 480 paddy fields obtained through comparative method on the following items are identical in general with those obtained at 18 paddy fields: Application of fertilizers, chemical spray for the control of disease, insects and pests both in the nursery and the paddy field, transplanting date, transplanting density, split application of fertilizers and yield n the paddy fields. a) The number of rice varieties used in the cooperative rice cultivation were 13 varieties while the individual rice cultivation used 47 varieties. b) The cooperative rice cultivation has more successfully adopted improved cultivation techniques such as the practice of seed disinfection, adoption of recommended seeding amount, fall ploughing, application of red soil, introduction of power tillers, the rectangular-type transplanting, midsummer drainage and the periodical irrigation. 9. The following results were also obtained from the same investigation and they are: a) In the cooperative rice cultivation, the greater part of the important practices have been carried out through cooperative operation including seed disinfection, ploughing, application of red soil and compost, the control of disease, insects and pests, harvest, threshing and transportation of the products. b) The labor input to the nursery bed and water control in the cooperative rice cultivation was less than that of the individual rice cultivation while the higher rate of labor input was resulted in the red soil and compost application. 10. From the investigation on the organization and operation scheme of the cooperative rice cultivation, the following results were obtained: a) The size of cooperative rice cultivation farm was varied from. 3 ha to 7 ha and 5 ha farm. occupied 55.9 percent of the total farms. And a single cooperative farm was consisted of 10 to 20 plots of paddies. b) The educational back ground of the staff members involved in the cooperative rice cultivation was superior than that of the individual rice cultivation. c) All of the farmers who participated to the questionaires have responded that the cooperative rice cultivation could promise the increased rice yield mainly through the introduction of the improved method of fertilizer application and the effective control of diseases, insects and pests damages. And the majority of farmers were also in the opinion that preparation of the materials and labor input can be timely carried out and the labor requirement for the rice cultivation possibly be saved through the cooperative rice cultivation. d) The farmers who have expressed their wishes to continue and to make further development of the cooperative rice cultivation was 74.5 percent of total farmers participated to the questionaires. 11. From the analysis of economical feasibility on the two different methods of cultivation, the following results were obtained: a) The value of operation cost for the compost, chemical fertilizers, agricultural chemicals and labor input in the cooperative rice cultivation was respectively higher by 335 won, 199 won, 288 won and 303 won over the individual rice cultivation. However, the other production costs showed no distinct differences between the two cultivation methods. b) Although the total value of expenses for the fertilizers, agricultural chemicals, labor input and etc. in the cooperative rice cultivation were approximately doubled to the amount of the individual rice cultivation, the net income, substracted operation costs from the gross income, was obtained 24, 302 won in the cooperative rice cultivation and 20, 168 won was obtained from the individual rice cultivation. Thereby, it can be said that net income from the cooperative rice cultivation increased 4, 134 won over the individual rice cultivation. It was revealed in this study that the cooperative rice cultivation has not only contributed to increment of the farm income through higher yield but also showed as an effective means to introduce highly improved cultivation techniques to the farmers. It may also be concluded, therefore, the cooperative rice cultivation shall continuously renovate the rice production process of the farmers.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.80-85
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• 2012

Purpose: The whole body bone scan is an examination that visualizing physiological change of bones and using bone-congenial radiopharmaceutical. The patients are intravenous injected radiopharmaceutical which labeled with radioactive isotope ($^{99m}Tc$) emitting 140 keV gammarays and scanned after injection. The 3 principles of radiation protection from external exposureare time, distance and shielding. On the 3 principles of radiation protection basis, radiopharmaceutical might just as well be injected rapidly for reducing radiation because it might be the unopened radiation source. However the radiopharmaceuticals are injected into patient directly and there is a limitation of distance control. This study confirmed the change of radiation exposure as change of distance from radiopharmaceutical and observed the change of radiation exposure afte rsetting a shelter for help to control radio-technician's exposure. Materials & methods: For calculate the average of injection time, the trained injector measured the injection time for 50 times and calculated the average (2 minutes). We made a source as filled the 99mTc-HDP 925 MBq 0.2 mL in a 1 mL syringe and measured the radiation exposure from 50 cm,100 cm,150 cm and 200 cm by using Geiger-Mueller counter (FH-40, Thermo Scientific, USA). Then we settled a lead shielding (lead equivalent 6 mm) from the source 25 cm distance and measured the radiation exposure from 50 cm distance. For verify the reproducibility, the measurement was done among 20 times. The correlation between before and after shielding was verified by using SPSS (ver. 18) as paired t-test. Results: The radiation doses according to distance during 2 minutes from the source without shielding were $1.986{\pm}0.052{\mu}$ Sv in 50 cm, $0.515{\pm}0.022{\mu}$ Sv in 100 cm, $0.251{\pm}0.012{\mu}$ Sv in 150 cm, $0.148{\pm}0.006{\mu}$ Sv in 200 cm. After setting the shielding, the radiation dose was $0.035{\pm}0.003{\mu}$ Sv. Therefore, there was a statistical significant difference between the radiation doses with shielding and without shielding ($p$<0.001). Conclusion: Because the great importance of whole body bone scan in the nuclear medicine, we should make an effort to reduce radiation exposure during radiopharmaceutical injections by referring the principles of radiation protection from external exposure. However there is a limitation of distance for direct injection and time for patients having attenuated tubules. We confirmed the reduction of radiation exposure by increasing distance. In case of setting shield from source 25 cm away, we confirmed reducing of radiation exposure. Therefore it would be better for reducing of radiation exposure to using shield during radiopharmaceutical injection.