• Journal of Radiation Protection and Research
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• v.42 no.2
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• pp.77-82
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• 2017

Background: This study aims to predict the midline dose based on the entrance and exit doses from optically stimulated luminescence detector (OSLD) measurements for total body irradiation (TBI). Materials and Methods: For TBI treatment, beam data sets were measured for 6 MV and 15 MV beams. To evaluate the tissue lateral effect of various thicknesses, the midline dose and peak dose were measured using a solid water phantom (SWP) and ion chamber. The entrance and exit doses were measured using OSLDs. OSLDs were attached onto the central beam axis at the entrance and exit surfaces of the phantom. The predicted midline dose was evaluated as the sum of the entrance and exit doses by OSLD measurement. The ratio of the entrance dose to the exit dose was evaluated at various thicknesses. Results and Discussion: The ratio of the peak dose to the midline dose was 1.12 for a 30 cm thick SWP at both energies. When the patient thickness is greater than 30 cm, the 15 MV should be used to ensure dose homogeneity. The ratio of the entrance dose to the exit dose was less than 1.0 for thicknesses of less than 30 cm and 40 cm at 6 MV and 15 MV, respectively. Therefore, the predicted midline dose can be underestimated for thinner body. At 15 MV, the ratios were approximately 1.06 for a thickness of 50 cm. In cases where adult patients are treated with the 15 MV photon beam, it is possible for the predicted midline dose to be overestimated for parts of the body with a thickness of 50 cm or greater. Conclusion: The predicted midline dose and OSLD-measured midline dose depend on the phantom thickness. For in-vivo dosimetry of TBI, the measurement dose should be corrected in order to accurately predict the midline dose.

• Radiation Oncology Journal
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• v.17 no.4
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• pp.321-328
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• 1999

Purpose : Total body irradiation (TBI) or whole body irradiation is used to acquire immune suppression, to treat malignant lymphoma and leukemia, and as an conditioning regimen for bone marrow transplantation. For these purposes, many methods were developed to obtain homogenous dose distribution. The objective of this study was to analyze and confirm the accuracy and the homogeneity of the treatment setup, the parallel opposed lateral technique, currently used in Seoul National University Hospital. Materials and Metheods : Surface dose data, measured with a thermoluminescent dosimeter, of 8 patients among 10 patients, who were given total body irradiation with the parallel opposed lateral technique between September 1996 to August 1998, at Seoul National University Hospital were analyzed. Surface doses were measured at the head, neck, axilla, thigh, and ankle level. Surface and midline doses were measured with similar set-up and technique in the Humanoid phantom. Results : Measured surface doses relative to prescribed dose for the head, neck, axilla, thight, and ankle leve were $91.3{\pm}7.8,{\;}98.3{\pm}7.5,{\;}95.1{\pm}6.3,{\;}98.3{\pm}5.5$, and $95.3{\pm} 6.3\%$, respectively. The midline doses of the head, neck, axilla, thigh, and ankle level estimated from the surface-to-midline ratios in the Humanoid Phantom were $103.4{\pm}9.0,{\;}107.8{\pm}10.5,{\;}91.1{\pm}6.1,{\pm} 93.8{\pm}4.5,{\;}and{\;}104.5{\pm}9.3\%$, respectively. Measured surface doses and estimated midline doses ranged from $-8.9\%$ to $+7.8\%$. Midline doses at the neck and the axilia level deviated more than $5\%$ from the prescribed doses. The difference of the estimated midline doses at the neck and the axilla level and the actual doses were attributed to the thickness differences between the Humanoid phantom and the patients. Conclusion Distribution of the midline doses as well as the suface doses were measured to be within $-8.7\~{\pm}7.8\%$ range. Actual dose distribution in the patient is expected to be better than the measured dose range mainly attributed to thickness difference between the patient and the Humanoid phantom.

• Radiation Oncology Journal
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• v.14 no.3
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• pp.201-209
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• 1996

Purpose : To assess the efficacy of high dose rate - intracavitary radio-therapy (HDR-ICR) in the radiotherapy of FIGO stage IB squamous cell carcinoma of uterine cervix and to determine the optimum dose combination scheme of external radiotherapy and ICR to achieve acceptable local control without severe complication. Materials and Methods : One hundred and sixty two patients with FIGO stage Ib squamous cell carcinoma of uterine cervix who received definitive radiotherapy between May 1979 and December 1990 were retrospectively analyzed. All the patients received external radiotherapy combined with HDR-ICR. External dose of 40-46 Gy in 4.5-5 weeks was given to whole pelvis(median 45 Gy) and ICR dose of 30-39 Gy in 10-13 times was given to the point A. Midline shielding was done after 20-45 Gy of external radiotherapy(median 40 Gy) Summation of external dose Plus ICR dose to the point A range were 64.20-95.00 Gy. and mean was 83.94 Gy. We analyzed the local control rate, survival rate, and late complication rate. Rusults : Initial complete response rate was $99.4\%$ for all patients. Overall 5-year survival rate was $91.1\%$ and 5-year disease free survival rate was $90.9\%$. Local failure rate was $4.9\%$ and distant failure rate was $4.3\%$. Tumor size was the only significant prognostic factor. When tumor size greater than 3cm, 5-rear survival rate was $92.6\%$ and less than 3cm, that was $79.6\%$. Late complication rate was $23.5\%$ with $18.5\%$ of rectal complication and $4.9\%$ of bladder complication. Mean rectal dose summation of external midline dose plus ICR rectal point dose was lower in the patients without rectal complication(74.88 Gr) than those with rectal complication (78.87 Gy). Complication rate was increased with low rate of improvement of survival rate when summation of external midline dose plus point A or point R dose by ICR was greater than 70-75 Gy. Conclusion : The definitive radiation therapy using high dose rate ICR in FIGO stage IB uterine cervical cancer is effective treatment modality with good local control and survival rate without severe complication.

• Radiation Oncology Journal
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• v.4 no.2
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• pp.135-139
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• 1986

Seven patients having midline granuloma received local irradiation from March 1983 to June 1986. Clinically, all of the 7 patients had pansinusitis with necrotic destruction of the involved sites and one case revealed colonic lesion. Each of the patients received a tumor dose of $4,000\~5,000 cGy/5\~6$ wks to the upper aerodigestive tract using a 6-MV linear accelerator. Complete and partial remission occured in 3 patients each, and in one case, the disease progressed despite of the irradiation.

• Progress in Medical Physics
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• v.7 no.2
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• pp.47-55
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• 1996

Total Body Irradiation(TBI) is one of the essential treatment modalities in bone marrow transplantation for leukemia and lymphoma. Various techniques and dose regimens were introduced with sevelal advantages and disadvantages. In TBI, lung block could reduce lung dose to 75％ of original beam for decreasing lung dose with homogenous total body irradiation. Accurate provision for specified dose and the desired homogeneity are essential before clinical total body irradiation. When performed in total body irradiation, the problem obtain uniform dose distribution in brain, neck, lung, umbilicus, pelvis and leg. Authors compared to dose distribution with method 1 and method 2. The method 1 used compensating filters for homogeneous dose distribution(Minesota University Method). The method 2 used fixing frame made in aeryl developing authors. Results were following. 1. Method 1 was showed dose distribution from 95.6％ to 100％, method 2 showed dose distribution from 95.4％ to 100％. 2. Method 2 was showed different to 3.4％ at skin region and midline in the brain. In the neck, showed different to 1.5％. In the umbilicus. showed different to 2.3％.

• Journal of Veterinary Clinics
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• v.40 no.1
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• pp.25-30
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• 2023

The ventral midline approach (VMA) and right flank approach (RFA) are common procedures for the sterilization of bitches. This study compared the different parameters viz. total duration of surgery, recovery time, and length of the incision as well as body temperature, heart rate, respiration rate, and SpO2 in each approach. Twenty (20) bitches were divided randomly for the RFA and VMA. Meloxicam (0.2 mg/kg) was administered subcutaneously half an hour before the induction to provide preemptive analgesia. Diazepam and ketamine were administered intravenously at dose rates of 0.25 mg/kg and 2.5 mg/kg, and 0.17 mg/kg and 3.33 mg/kg, respectively to produce and maintain anesthesia. Each parameter was recorded at the pre-operative, operative and post-operative times. The average duration of surgery and length of incision of RFA (16.1 ± 5.13 min and 2.44 ± 0.83 cm) were significantly lower (p < 0.05) than the VMA (21.3 ± 5.48 min and 3.53 ± 0.7 cm). The operated bitches showed hypothermia (p < 0.05) at 1 hour compared to baseline and 24 hours of surgery. Heart and respiration rates increased significantly (p < 0.05) during traction and severing of ovarian ligaments in bitches within the RFA group, but there was no significant difference within VMA approaches. The sedation score was significantly higher (p < 0.05) at 1 hour after surgery in both approaches. Based on the duration of surgery and length of incision RFA approach was quick and minimal skin wound. Further studies on bitches considering molecular investigations of surgical stress are imperative.

• Radiation Oncology Journal
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• v.1 no.1
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• pp.69-77
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• 1983

20 cases of midline pineal tumors and 3 suprasellar germinomas received radiation therapy at Yonsei University Medical College, Severance hospital from 1971 to 1982 were reviewed. 12 cases were pathologically proved; 10 germinomas, 1 pineoblastoma, and 1 pineocytoma. 11 cases received radiotherapy without biopsy confirmation. Although treatment fields varied from small field to whole brain irradiation, but not to the spinal cord, most patients received 4000-5000 rads irradiation to the primary tumor site. 17 patients are alive without evidence of disease and 5 year actuarial NED survival is 73.2%. 9 of 10 biopsy proved germinomas and all 6 presumed germinomas are alive and well. Optimum radiation dose, adequate irradiation field, tumor response to radiation observed in serial CT scan and role of radiation therapy in the management of pineal tumors are also discussed.

• Progress in Medical Physics
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• v.6 no.2
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• pp.21-28
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• 1995

In recent years there has been a growing interest in total body irradiation. For refractory leukemia or lymphoma patients, varions techniques and dose regimens were intridused, including high dose total body irradiation for destruction of leukemic or bone marrow cells and immunosupperression prior to bone marrow transplantation. Accurate provision for specified dose and the desired homogeneity are essential before clinical total body irradiatio. When performed in total body irradiation, the problem obtain uniform uniform dose distribution in brain, neck, lung, umbilicus, pelvis and leg. Authors compared to dose distribution with method 1 and method 1. The method 1 used compensationg filters for homogeneous dose distribution(Minesota University Method). The method 2 used fixing frame made in acryl developing authors. Results were following 1. Method 1 was showed dose distribution from 95.6％ to 100％, method 2 showed dose distribution from 95.4％ to 100％ 2. Method 2 was showed different to 3.4％ at skin region and midline in the brain. In the neck, showed different to 1.5％. In the umbilicus, showed different to 2.3％.

• Radiation Oncology Journal
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• v.23 no.3
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• pp.143-156
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• 2005

Background: The best dose-fractionation regimen of the definitive radiotherapy for cervix cancer remains to be clearly determined. It seems to be partially attributed to the complexity of the affecting factors and the lack of detailed information on external and intra-cavitary fractionation. To find optimal practice guidelines, our experiences of the combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) were reviewed with detailed information of the various treatment parameters obtained from a large cohort of women treated homogeneously at a single institute. Materials and Methods: The subjects were 743 cervical cancer patients (Stage IB 198, IIA 77, IIB 364, IIIA 7, IIIB 89 and IVA 8) treated by radiotherapy alone, between 1990 and 1996. A total external beam radiotherapy (EBRT) dose of $23.4\~59.4$ Gy (Median 45.0) was delivered to the whole pelvis. High-dose-rate intracavitary brachytherapy (HDR-IBT) was also peformed using various fractionation schemes. A Midline block (MLB) was initiated after the delivery of $14.4\~43.2$ Gy (Median 36.0) of EBRT in 495 patients, while In the other 248 patients EBRT could not be used due to slow tumor regression or the huge initial bulk of tumor. The point A, actual bladder & rectal doses were individually assessed in all patients. The biologically effective dose (BED) to the tumor ($\alpha/\beta$=10) and late-responding tissues ($\alpha/\beta$=3) for both EBRT and HDR-ICBT were calculated. The total BED values to point A, the actual bladder and rectal reference points were the summation of the EBRT and HDR-ICBT. In addition to all the details on dose-fractionation, the other factors (i.e. the overall treatment time, physicians preference) that can affect the schedule of the definitive radiotherapy were also thoroughly analyzed. The association between MD-BED $Gy_3$ and the risk of complication was assessed using serial multiple logistic regression models. The associations between R-BED $Gy_3$ and rectal complications and between V-BED $Gy_3$ and bladder complications were assessed using multiple logistic regression models after adjustment for age, stage, tumor size and treatment duration. Serial Coxs proportional hazard regression models were used to estimate the relative risks of recurrence due to MD-BED $Gy_{10}$, and the treatment duration. Results: The overall complication rate for RTOG Grades $1\~4$ toxicities was $33.1\%$. The 5-year actuarial pelvic control rate for ail 743 patients was $83\%$. The midline cumulative BED dose, which is the sum of external midline BED and HDR-ICBT point A BED, ranged from 62.0 to 121.9 $Gy_{10}$ (median 93.0) for tumors and from 93.6 to 187.3 $Gy_3$ (median 137.6) for late responding tissues. The median cumulative values of actual rectal (R-BED $Gy_3$) and bladder Point BED (V-BED $Gy_3$) were 118.7 $Gy_3$ (range $48.8\~265.2$) and 126.1 $Gy_3$ (range: $54.9\~267.5$), respectively. MD-BED $Gy_3$ showed a good correlation with rectal (p=0.003), but not with bladder complications (p=0.095). R-BED $Gy_3$ had a very strong association (p=<0.0001), and was more predictive of rectal complications than A-BED $Gy_3$. B-BED $Gy_3$ also showed significance in the prediction of bladder complications in a trend test (p=0.0298). No statistically significant dose-response relationship for pelvic control was observed. The Sandwich and Continuous techniques, which differ according to when the ICR was inserted during the EBRT and due to the physicians preference, showed no differences in the local control and complication rates; there were also no differences in the 3 vs. 5 Gy fraction size of HDR-ICBT. Conclusion: The main reasons optimal dose-fractionation guidelines are not easily established is due to the absence of a dose-response relationship for tumor control as a result of the high-dose gradient of HDR-ICBT, individual differences In tumor responses to radiation therapy and the complexity of affecting factors. Therefore, in our opinion, there is a necessity for individualized tailored therapy, along with general guidelines, in the definitive radiation treatment for cervix cancer. This study also demonstrated the strong predictive value of actual rectal and bladder reference dosing therefore, vaginal gauze packing might be very Important. To maintain the BED dose to less than the threshold resulting in complication, early midline shielding, the HDR-ICBT total dose and fractional dose reduction should be considered.

• Radiation Oncology Journal
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• v.12 no.2
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• pp.233-241
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• 1994

Purpose : This study was performed to verify dose distribution with the tissue compensator which is used for uniform dose distribution in total body irradiation(TBI). Materials and methods : The compensators were made of lead(0.8mm thickness) and aluminum(1mm or 5mm thickness) plates. The humanoid phantom of adult size was made of paraffin as a real treatment position for bilateral total body technique. The humanoid phantom was set at 360cm of source-axis distance(SAD) and irradiated with geographical field size(FS) $144{\times}144cm^2(40{\times}40cm^2$ at SAD 100cm) which covered the entire phantom. Irradiation was done with 10MV X-ray(CLINAC 1800, Varian Co., USA) of linear accelerator set at Department of Therapeutic Radiology, Chonnam University Hospital. The midline absorbed dose was checked at the various regions such as head, mouth, mid-neck, sternal notch, mid-mediastinum, xiphoid, umbilicus, pelvis, knee and ankle with or without compensator, respectively. We used exposure/exposure rate meter(model 192, Capintec Inc., USA) with ionization chamber(PR 05) for dosimetry, For the dosimetry of thorax region TLD rods of $1x1x6mm^3$ in volume(LiF, Harshaw Co., Netherland) was used at the commercially available humanoid phantom. Results : The absorbed dose of each point without tissue compensator revealed significant difference(from $-11.8\%\;to\;21.1\%$) compared with the umbilicus dose which is a dose prescription point in TBI. The absorbed dose without compensator at sternal notch including shoulder was $11.8\%$ less than the dose of umbilicus. With lead compensator the absorbed doses ranged from $+1.3\%\;to\;-5.3\%$ except mid-neck which revealed over-compensation($-7.9\%$). In case of aluminum compensator the absorbed doses were measured with less difference(from $-2.6{\%}\;to\;5.3\%$) compared with umbilicus dose. Conclusion : Both of lead and aluminum compensators applied to the skull or lower leg revealed a good compensation effect. It was recognized that boost irradiation or choosing reference point of dose prescription at sternal notch according to the lateral thickness of patient in TBI should be considered.