• Radiation Oncology Journal
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• v.8 no.2
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• pp.231-239
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• 1990

From May 1979 through December 1981 a total of 524 patients with carcinoma of the uterine cervix were treated by radiation therapy with curative intent. Among the 524 patients, 350 were treated with a high-dose-rate (HDR), remote-controlled, afterloading intracavitary irradiation (ICR) system using a cobalt source (Ralstron), and 168 patients received a low-dose-rate (LDR) ICR using a radium source. External beam irradiation with a total dose of 40-50 Gy to the whole pelvis followed by intracavitary irradiation with a total dose of 30-39 Gy in 10-13 fractions to point A was the treatment protocol. ICR was given three times a week with a dose of 3 Gy per fraction. Five-year actuarial survival rates in the HDR-ICR group were $77.6{\%}$ in stage IB (N=20), $68.2{\%}$ in stage II (N=182), and $50.9{\%}$ in stage III (N=148). In LDR-ICR group, 5-year survival rates were $87.5{\%}$ in stage IB (N=22), $66.3{\%}$ in stage II (N=91), and $55.4{\%}$ in stage III (N=52). Survival rates showed a statistically significant difference by stage, but there was no significant difference between the two ICR groups. Late bowel complications after radiotherapy were noted in $3.7{\%}$ of the HDR-ICR group and $8.4{\%}$ of the LDR-ICR group. There was no severe complication requiring surgical management. The incidence of bladder complications was $1.4{\%}$ in the HDR-ICR group and $2.4{\%}$ in the LDR-ICR group. The application of HDR-ICR was technically simple and easily performed on an outpatient basis without anesthesia, and the patients tolerated it very well. Radiation exposure to personnel was virtually nil in contrast to that of LDR-ICR. Within a given period of time, more patients can be treated with HDR-ICR because of the short treatment time. Therefore, the HDR-ICR system is highly recommended for a cancer center, particularly one with a large number of patients to be treated. In order to achieve an improved outcome, however, the optimum dose-fractionation schedule of HDR-ICR and optimum combination of intracavitary irradiation with external beam irradiation should be determined through an extensive protocol.

• The Journal of Korean Society for Radiation Therapy
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• v.25 no.1
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• pp.57-67
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• 2013

Purpose: Replacing the film which used to be used for checking the set-up of the patient and dosimetry during radiation therapy, more and more EPID equipped devices are in use at present. Accordingly, this article tried to evaluated the accuracy of the position check-up and the usefulness of dosimetry during the use of an electronic portal imaging device. Materials and Methods: On 50 materials acquired with the search of Korea Society Radiotherapeutic Technology, The Korean Society for Radiation Oncology, and Pubmed using "EPID", "Portal dosimetry", "Portal image", "Dose verification", "Quality control", "Cine mode", "Quality - assurance", and "In vivo dosimetry" as indexes, the usefulness of EPID was analyzed by classifying them as history of EPID and dosimetry, set-up verification and characteristics of EPID. Results: EPID is developed from the first generation of Liquid-filled ionization chamber, through the second generation of Camera-based fluoroscopy, and to the third generation of Amorphous-silicon EPID imaging modes can be divided into EPID mode, Cine mode and Integrated mode. When evaluating absolute dose accuracy of films and EPID, it was found that EPID showed within 1% and EDR2 film showed within 3% errors. It was confirmed that EPID is better in error measurement accuracy than film. When gamma analyzing the dose distribution of the base exposure plane which was calculated from therapy planning system, and planes calculated by EDR2 film and EPID, both film and EPID showed less than 2% of pixels which exceeded 1 at gamma values (r%>1) with in the thresholds such as 3%/3 mm and 2%/2 mm respectively. For the time needed for full course QA in IMRT to compare loads, EDR2 film recorded approximately 110 minutes, and EPID recorded approximately 55 minutes. Conclusion: EPID could easily replace conventional complicated and troublesome film and ionization chamber which used to be used for dosimetry and set-up verification, and it was proved to be very efficient and accurate dosimetry device in quality assurance of IMRT (intensity modulated radiation therapy). As cine mode imaging using EPID allows locating tumors in real-time without additional dose in lung and liver which are mobile according to movements of diaphragm and in rectal cancer patients who have unstable position, it may help to implement the most optimal radiotherapy for patients.

• Radiation Oncology Journal
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• v.12 no.1
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• pp.81-90
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• 1994

Purpose : The aim of this study is to analyze the clinical results of thermo-irradiation treatment for surgically unresectable advanced hepatoma with or without hepatic arterial chemo-embolization (HACE), chemotherapy (CT) and interferon (IFN) therapy. Materials and Methods : Between February 1990 and December 1992, 45 Patients with surgically unresectable advanced hepatomas were treated by thermo-irradiation with or without hepatic arterial chemo-embolization and other treatment modalities. Among them, We analyzed retrospectively 25 patients who received more than three times of hyperthermias. Mean age was 50 years (range : 18-71 years) and male to female ratio was 20 : 5. In the study, treatment was administered as follows : 3 patients received radiation therapy(RT) and hyperthermia (HT). 3 received RT+HT+CT. 3 received RT+HT+HACE. 1 received RT+HT+CT+HACE. 2 received RT+HT+CT+IFN. 10 received RT+HT+HACE+IFN. 3 received RT+HT+CT+HACE+IFN. Radiation therapy was done by a 6 MV linear accelerator Patients were treated with daily fractions of 180 cGy to doses of 11Gy-50Gy (median 30Gy). Local hyperthermia was done by HEH-500C(Omron Co. Japan), 30-45 min/session, 2 sessions/wk and the number of HT sessions ranged from 3 to 17 (median 7 times). 15 patients of 25 were followed by abdominal CT scan or abdominal ultra-sonogram. The following factors were analyzed :Age, histologic grade, sex. number of hyperthermia, total RT dose, hepatic arterial chemo-embolization. Results : Of 25 patients. there were observed tumor regression (partial response and minimal response) in 6 (24$ \% $), no response in 8 (32$ \% $), progression in 1 (4$ \% $) and not evaluable ones in 10 (40$ \% $) radiographically. The over all 1-year survival was 25$ \% $, with a mean survival of 33 weeks. The treatment modes of partial and minimal responsive patients (PR+MR)were as follows : Two were treated with RT+HT+HACE, 2 were done with RT+HT+HACE+IFN Remaining 2 were treated with RT+HT+CT+HACE+IFN. The significant factor affecting the survival rate were RT dose (more than 25 Gy), HACE, number of HT (above 6 times), responsiveness after treatment (PR + MR). Age, sex, histologic differentiation, chemotherapy, interferon therapy were not statistically significant factors affecting the survival rate. Conclusion : Although follow-up duration was short, the thermo-irr3diBtion with/without hepatic arterial chemo-embolization was well tolerated and there were no serious complicatons. In future, it is considered the longer follow up and prospective, well controlled trials should be followed to evaluate the efficacies of survival advantage.

• Radiation Oncology Journal
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• v.18 no.1
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• pp.40-45
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• 2000

Purpose : To evaluate the histopathological prognostic factors, relapse pattern and survival in patients with endometrial carcinoma who were treated with surgery and postoperative adjuvant radiotherapy (RT). Methods and Materials : From September 1991 to December 1997, 27 patients with endometrial carcinoma treated with surgery and postoperative adjuvant RT at Asan Medical Center were entered in this study. Surgery was peformed with total abdominal hysterectomy in six, total abdominal hysterectomy with pelvic lymph node dissection in eight and radical hysterectomy in 13 patients. External RT of 50.4 Gy was done to all patients and among these, additional high dose rate vaginal vault irradiation of 20$\~$25 Gy with fractional dose of 4$\~$5 Gy was boosted In 16 patients. The patients were followed for 6$\~$95 months(median 30). Results : The number of patients according to FIGO stage were I 18 (67$\%$), II 1 ($4\%$) and III 7 ($26\%$). Patients with poor histologic grade, deep myometrial invasion, adnexal involvement, lymphovascular invasion showed more pelvic lymph node involvement, but no statistical significance was indicated. The 5 year overall and disease free survival were 100$\%$ and 76.8$\%$, respectively. Relapse sites were pelvic, para-aortic lymph node, and multiple metastases including lung, and no vaginal relapse was developed. Factors that were associated with disease free survival were FIGO stage (p=0.01), lymphovascular invasion (p=0.03), pelvic lymph node involvement (p=0.0001). There was only one Grade 1 rectal bleeding without moderate to severe complications. Conclusion : Postoperative adjuvant RT is considered to reduce the loco-regional failure, resulting the improvement of survival. The group of patients with the risk of vaginal failure without vaginal vault irradiation should be investigated according to stage and grade.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.150-156
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• 2000

Purpose : Stereotactic radiation therapy (SRT) can deliver highly focused radiation to a small and spherical target lesion with very high degree of mechanical accuracy. For non-spherical and large lesions, however, inclusion of the neighboring normal structures within the high dose radiation volume is inevitable in SRT This is to report the beam shaping using the partial closure of the independent jaw in SRT and the verification of dose calculation and the dose display using a home-made soft ware. Materials and Methods : Authors adopted the idea to partially close one or more independent collimator jaw(5) in addition to the circular collimator cones to shield the neighboring normal structures while keeping the target lesion within the radiation beam field at all angles along the arc trajectory. The output factors (OF's) and the tissue-maximum ratios (TMR's) were measured using the micro ion chamber in the water phantom dosimetry system, and were compared with the theoretical calculations. A film dosimetry procedure was peformed to obtain the depth dose profiles at 5 cm, and they were also compared with the theoretical calculations, where the radiation dose would depend on the actual area of irradiation. Authors incorporated this algorithm into the home-made SRT software for the isodose calculation and display, and was tried on an example case with single brain metastasis. The dose-volume histograms (DVH's) of the planning target volume (PTV) and the normal brain derived by the control plan were reciprocally compared with those derived by the plan using the same arc arrangement plus the independent collimator jaw closure. Results : When using 5.0 cm diameter collimator, the measurements of the OF's and the TMR's with one independent jaw set at 30 mm (unblocked), 15.5 mm, 8.6 mm, and 0 mm from th central beam axis showed good correlation to the theoretical calculation within 0.5% and 0.3% error range. The dose profiles at 5 cm depth obtained by the film dosimetry also showed very good correlation to the theoretical calculations. The isodose profiles obtained on the home-made software demonstrated a slightly more conformal dose distribution around the target lesion by using the independent jaw closure, where the DVH's of the PTV were almost equivalent on the two plans, while the DVH's for the normal brain showed that less volume of the normal brain receiving high radiation dose by using this modification than the control plan employing the circular collimator cone only. Conclusions : With the beam shaping modification using the independent jaw closure, authors have realized wider clinical application of SRT with more conformal dose planning. Authors believe that SRT, with beam shaping ideas and efforts, should no longer be limited to the small spherical lesions, but be more widely applied to rather irregularly shaped tumors in the intracranial and the head and neck regions.

• Radiation Oncology Journal
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• v.5 no.2
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• pp.97-104
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• 1987

From January 1970 through December 1984, 15 patients with sinonasal Non-Hodgkin's lymphoma combined to the head and neck were treated by external irradiation.13 patients were stage It and 2 were stage IIE by Ann Arbor Classification. However, when using TNM system, 7 were locally advanced T3, T4 lesions. All patients had follow up from 3.7 to 16 years with the median follow-up of 8.5 years. The overall actuarial 5-year survival rates were $25\%,\;28\%$ for IE and $0\%$ for IIE. Total tumor dose varied from 40 to 68 Gy. $100\%$ complete response with a total tumor dose of more than 55 Gy and $73\%$ complete response with less than 55Gy. When the disease was staged using the TNM (AJC) system, the five-year disease free survival for T1 and T2 patients was $50\%$ as compared with $14\%$ for T3 and T4. Failure rate by stage was $33\%(2/6)$ for T1 and T2, $86\%(6/7)$ for T3 and T4, and $100\%$(2/2) for IIE. The results suggest that 1. Higher CR could be obtained with a total tuner dose of more than 55 Gy. 2. Use of TNM staging system is as important as Ann arbor in management of sinonasal NHL. 3. The addition of combination chemotherapy should be considered for T3, T4 and IIE the sinonasal Non-Hodgkin's lymphoma although the disease is limited to head and neck.

• Radiation Oncology Journal
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• v.15 no.4
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• pp.305-313
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• 1997

Purpose : This is a retrospective study to evaluate the results of radiation therapy and prognostic factors influencing the results in nasopharyngeal carcinoma. Materials and Methods: From October 1989 to May 1996. 56 Patients were treated for nasopharyngeal carcinoma at Department of Radiation On-cology. According to stage, patients were distributed as follows : stage I (2), II (13). II (11), IV (30). Twenty-eight patients were treated with radiation therapy only, 7 patients were treated with neoadiuvant chemotherapy followed by radiation therapy. Twenty-one Patients were treated with radiation therapy and weekly CDDP. After external beam radiotherapy of 60Gy, 46Patients received boost dose with intracavitary radiation and 9 Patients with 3D conformal therapy. One patient received boost dose with 2 dimensional Photon beam therapy. The tumor dose ranged from 69.4Gy to 86.2Gy with median dose of 74.4Gy. The follow-up Period ranged from 5 months to 92 months with a median of 34 months. Results : Forty-seven patients achieved complete response and 8 Patients showed partial response. One Patient showed minimal response. Patterns of failure were as follows : locoregional recurrence (8) and distant metastasis (18). Among these patients, 2 patients failed locoregionally and distantly. The sites of distant metastasis were bone (8), lung (8) and liver (4). Five years survival rate was $67.2\%$ and 5 years disease-free survival rate was $53.6\%$. KPS (P=0.005) and response ol radiation therapy (P=0.0001) were significant prognostic factors for overall survival. KPS (P= 0.02) and response of radiation therapy (P=0.005) were significant Prognostic factors for disease-free survival. Conclusion : This retrospective study showed that distant metastasis was the Predominant pattern of relapse in nasopharyngeal cancer Neoadiuvant chemotherapy or weekly CDOP did not influence the distant metastasis-free survival. For advanced T stage, 3D conformal therapy Provided an improved dose coverage compared to ICR But further follow-up was needed in Patients with 3D conformal therapy to assess the efficacy of this therapy. Development of techniques of radiation therapy to improve locoregional control and of more effective systemic chemotherapy regimen are needed.

• Radiation Oncology Journal
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• v.16 no.2
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• pp.167-175
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• 1998

Purpose : It is not a simple task to achieve the ideal isodose curve with a standard vaginal applicator or sing1e plane needle impant in the paravaginal tissue when primary or recurrent gynecological neoplasms(cervical cancers, vaginal cancers and vulvar cancers) are treated as a boost following external beam radiotherapy. The authors introduce the development and construction of a simple, inexpensive, customized applicator for volume implant to maximize the radiation dose to the tumor while minimizing the dose to the rectum and the bladder. Materials and Methods : Nine patients underwent Ir-192 transperineal interstitial implantation for either recurrent(5 cases) or primary(3 cases) cervical cancers or primary vaginal cancer(1 case) between August 1994 and February 1998 at Ajou university hospital. First 3 cases were performed with a sing1e plane implant guided by digital palpation. Because of inadequate isodose coverage in the tumor volume in first 3 cases, we designed and constructed interstitial vaginal applicator for volume implant to improve tumor dose distribution and homogeneity while sparing the surrounding normal tissue. Our applicators consist of vaginal obturator and perineal template that made of the clear acrylamide and dental mold material$(Provil^{(R)})$. The applicators were customized individually according to the tumor size and its location Both HDR and LDR irradiation were given with these applicators accomodating 6 Fr needles(Microselectron Nucletron). The pretreatment planning prior to actual implant was performed whenever possible. Results : Needles can be inserted easily and evenly into the tumor volume through the holes of templates, requiring less efforts and time for the implant procedure. Our applicators made of materials available from commercial vendors. These have an advantage that require easy procedure, and spend relatively short time to construct. Also it was possible to fabricate applicators to individualize according to the tumor size and its location and to achieve the ideal isodose coverage. We found an accurate needle arrangement and ideal dose distribution through the CT scan that was obtained in 3 cases after needle implant. Three patients with primary cervical and vaginal cancers were controlled locally at final follow up. But all recurrent cases failed to do so. Conclusion : The authors introduce inexpensive, simple interstitial vaginal templates which were self-designed and constructed using materials available from commercial vendors such as acrylanide and dental mold material $(Provil^{(R)})$.

• Journal of Radiation Protection and Research
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• v.25 no.1
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• pp.31-36
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• 2000

In radiotherapy, it may happen to radiate surrounding normal tissue because of inconsistent field size by changing patient position during treatment. We are going to analyze errors reduced by using immobilization device with Electonic portal imaging device(EPID) in this study. We had treated the twenty-one patients in pelvic region with 10 MV X-ray from Aug. 1998 to Aug. 1999 at Chungnam National University Hospital. All patients were treated at supine position during treatment. They were separated to two groups, 11 patients without device and 10 patients with immobilization device. We used styrofoam for immobilization device and measured the errors of anterior direction for x, y axis and lateral direction for z, y axis from simulation film to EPID image using matching technique. For no immobilization device group, the mean deviation values of x axis and y axis are 0.19 mm. 0.48 mm, respectively and the standard deviations of systematic deviation are 2.38 mm, 2.19 mm, respectively and of random deviation for x axis and y axis are 1.92 mm. 1.29 mm, respectively. The mean deviation values of z axis and y axis are -3.61 mm. 2.07 mm, respectively and the standard deviations of systematic deviation are 3.20 mm, 2.29 mm, respectively and of random deviation for z axis and y axis are 2.73 mm. 1.62 mm, respectively. For immobilization device group, the mean deviation values of x axis and y axis are 0.71 mm. -1.07 mm, respectively and the standard deviations of systematic deviation are 1.80 mm, 2.26 mm, respectively and of random deviation for x axis and y axis are 1.56 mm. 1.27 mm, respectively. The mean deviation values of z axis and y axis are -1.76 mm. 1.08 mm, respectively and the standard deviations of systematic deviation are 1.87 mm, 2.83 mm, respectively and of random deviation for x axis and y axis are 1.68 mm, 1.65 mm, respectively. Because of reducing random and systematic error using immobilization device, we had obtained good reproducibility of patient setup during treatment so that we recommend the use of immobilization device in pelvic region of radiation treatment.

• Radiation Oncology Journal
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• v.26 no.4
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• pp.257-262
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• 2008

Purpose: Oral mucositis induced by radiotherapy to the head and neck area, is a common acute complication and is considered as the most severe symptom for cancer patients in the early stages of treatment. This study was proposed to establish the oral mucositis mouse model induced by a single dose of radiation for the facility of testing therapeutic candidates which can be used for the oral mucositis treatments. Materials and Methods: Fifty-five BALB/c mice were divided into four groups: control, 16 Gy, 18 Gy, and 20 Gy. Oral mucositis was induced by a single dose of radiation to the head and neck using 6 MV x-Ray from linear accelerator. After irradiation, body weight and physical abnormalities were checked daily. Tongue tissues from all groups were taken on days 1, 2, 3, 5, 7, 9, and 14, respectively and H&E staining was conducted to examine morphological changes. Results: Body weight dramatically decreased after day 5 in all irradiated mice. In the 16 Gy treatment group, body weight was recovered on day 14. The histology data showed that the thickness of the epithelial cell layer was decreased by the accumulated time after radiation treatment, up to day 9. Severe ulceration was revealed on day 9. Conclusion: A single dose of 16 Gy is sufficient dose to induce oral mucositis in Balb/C mice. Significant changes were observed in the Balb/C mice on days 7 and 9 after radiation. It is suggested that this mouse model might be a useful standard tool for studying oral mucositis induced by radiation.