• Radiation Oncology Journal
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• v.13 no.3
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• pp.259-266
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• 1995

Purpose : The aim of this study is to analyze the survival rate, treatment failure and complication of radiation therapy alone in stage III uterine cervical cancer. Materials and Methods : From January 1980 through December 1985, 227 patients with stage III uterine cervical cancer treated with radiation therapy at Kosin Medical Center were retrospectively studied. Among 227 patients, 72 patients($317{\%}$) were stage IIIa, and 155 patients($68.3{\%}$) were stage IIIb according to FIGO classification. Age distribution was 32-71 years (median: 62 years). Sixty nine patients($95.8{\%}$) in stage IIIa and 150 patient ($96.8{\%}$) in stage IIIb were squamous cell carcinoma. pelvic lymph node metastasis at initial diagnosis was 8 patients($11.1{\%}$) in stage IIIa and 29 patients($18.7{\%}$) in stage IIIb, Among 72 patients with stage IIIa, 36 patients ($50{\%}$) were treated with external radiation therapy alone by conventional technique (180-200 cGy/fr.) and 36 patients($50{\%}$) were treated with external radiation therapy with intracavitary radiotherapy(ICR) with $Cs^{137}$ sources, and among 155 patients with stage IIIb, 80 patients ($51.6{\%}$) were treated with external radiation therapy alone and 75 patients ($48.4{\%}$) were treated with external radiation therapy with ICR. Total radiation doses of stage IIIa and IIIb were 65-105 Gy(median: 78.5 Gy) and 65-125.5 Gy (median 83.5 Gy). Survival rate was calculated by life-table method. Results : Complete response rates were $58.3{\%}$(42 patients) in stage IIIa and $56.1{\%}$(87 patients) in stage IIIb. Overall 5 year survival rates were $57{\%}$ in stage IIIa and $40{\%}$ in stage IIIb. Five year survival rates by radiation technique in stage IIIa and IIIb were $64{\%},\;40{\%}$ in the group treated in combination of external radiation and ICR, and $50\%,\;40\%$ in the group of external radiation therapy alone(P=NS). Five year survival rates by response of radiation therapy in stage IIIa and IIIb were $90\%,\;66\%$ in responder group and $10\%,\;7\%$ in non-responder group (P<0.001) There were statistically no significant differences of 5 year survival rate by total radiation doses and external radiation doses(40 Gy vs 50 Gy) of whole or true pelvis in stage IIIa and IIIb(P=NS). Treatment failures rates were $40.3\%$(29 patients) in stage IIla and $57.4\%$(89 patients) in stage IIIb. 17 patients ($23.6\%$) in stage IIIa and 46 patients ($29.7\%$) in stage IIIb experienced complications. Total radiation doses more than 85 Gy produced serious complication in both stage IIIa($50\%$) and IIIb($50\%$). Serious complication rates were higher in group received external radiation doses of 50 Gy than 40 Gy to whole or true pelvis in stage IIIa and IIIb. Serious rectal complication developed in rectal doses more than 65 Gy, and serious bladder complication developed in bladder doses more than 75 Gy. Major cause of death was cachexia due to locoregional failure in both stage IIIa($34.7\%$) and IIIb($43.9\%$). Conclusion : From this study, we found that external radiation therapy with ICR was found to have a tendency to be superior to external radiation therapy alone in survival rate, local control rate and complication rate but not different in statistics, and external radiation doses of 50 Gy than 40 Gy to whole or true pelvis produced serious rectal and bladder complications in stage III uterine cervical cancer.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.37-42
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• 2014

Purpose : At the time of the pelvis cancer radiation treatment using the belly board, set-up error is large because of a prone position. In order to improve the reproducibility, we made Vac-lock type belly board. In this study, we attempt to validate its utility. Materials and Methods : We compared belly board and Vac-lock type belly board through the OBI. OBI was performed three times with entire course of treatment and the setup errors in the direction of X axis, Y axis, Z axis were recorded and calculated the distance from the isocenter. Results : X axis, Y axis, Z axis setup errors with existing belly board were 0.32 cm, 0.41 cm, 0.29 cm. The setup errors with the vac-lock type belly board were 0.12 cm, 0.19 cm, 0.17 cm. Further, errors of 0~0.29 cm were increased from 48% to 83% when using VLT belly board. Error of 0.5 cm or more was reduced from 21% to 2%. Conclusion : Vac-lock type belly board is able to maintain the efficacy of existing and create to match the characteristics of the patient. Therefore We think that vac-lock type belly board is very useful in pelvic cancer patients.

• Radiation Oncology Journal
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• v.17 no.1
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• pp.36-41
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• 1999

Purpose : We reviewed the treatment results for the patients with locally recurrent rectal carcinoma. The object was to evaluate the treatment outcome and to identify the prognostic factors influencing the survival. Methods and Materials: Twenty-eight patients with locally recurrent rectal carcinoma treated principally with external-beam radiation therapy between 1982 to 1996 in the Department of Radiation Oncology at Paik and Hanyang Hospital were reviewed retrospectively Of these, 17 patients had initially abdominoperineal resection, 9 had low anterior resection, and 2 had local excision. No patients had received adjuvant radiation therapy for the primary disease. There were 14 men and 14 women whose ages ranged from 31 to 72 years (median age:54.5). Median time from initial surgery to the start of radiation therapy for local recurrence was 11 months (4~47 months). Radiation therapy was given with total doses ranging from 27 to 64.8 Gy (median=51.2 Gy). Results : The median survival was 16.7 months. The 2-year and 5-year survival rates were 20.1%, 4.1% respectively. Upon multivariate analysis, overall survival was positively correlated with duration of intervals from initial surgery to local recurrence (P=0.039). Relief of pelvic symptoms was achieved in 17 of 28 patients (60.7%). Pain and bleeding responded in 40% and 100% of patients, respectively Conclusions : Patients with locally recurrent rectal carcinoma treated with radiotherapy have benefited symptomatically, and might have increased survivals with a small chance of cure. But, patient were rarely cured (median survival : 10 months, 5-year survival : less than 5%). Overall survival was positively correlated with long intervals from initial surgery to local recurrence. Future efforts should be directed to the use of effective therapy for patients with locally recurrent rectal carcinoma and adjuvant therapy for patients with rectal cancer to reduce the incidence of pelvic recurrence.

• Journal of Radiation Protection and Research
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• v.49 no.2
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• pp.68-77
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• 2024

Background: Cone beam computed tomography (CBCT) is essential for correcting and verifying patient position before radiation therapy. However, it poses additional radiation exposure during CBCT scans. Therefore, this study aimed to evaluate radiological safety for the human body through dose assessment for CBCT. Materials and Methods: For CBCT dose assessment, the depth dose was evaluated using a cheese phantom, and the dose in the orbital area was evaluated using a human body phantom self-fabricated with a three-dimensional printer. Results and Discussion: The evaluation of radiation doses revealed maximum doses of 14.14 mGy and minimum doses of 6.12 mGy for pelvic imaging conditions. For chest imaging conditions, the maximum doses were 4.82 mGy, and the minimum doses were 2.35 mGy. Head imaging conditions showed maximum doses of 1.46 mGy and minimum doses of 0.39 mGy. The eyeball doses using a human body phantom model averaged at 2.11 mGy on the left and 2.19 mGy on the right. The depth dose ranged between 0.39 mGy and 14.14 mGy, depending on the change in depth for each imaging mode, and the average dose in the orbit area using a human body phantom was 2.15 mGy. Conclusion: Based on the experimental results, CBCT did not significantly affect the radiation dose. However, it is important to maintain a minimal radiation dose to optimize radiation protection following the as low as reasonable achievable principle.

• Radiation Oncology Journal
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• v.15 no.3
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• pp.263-268
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• 1997

Purpose : Authors designed a customized Small Bowel Displacement System (SBDS) to displace the small bowel from the Pelvic radiation fields and minimize treatment-related bowel morbidities. Materials and Methods : From August 1995 to Mar 1996. 55 consecutive patients who received pelvic radiation therapy with the SBDS were included in this study. The SBDS consists of a customized styrofoam compression device which can displace the small bowel from the radiation fields and an individualized immobilization abdominal board for easy daily setup in prone position After opacifying the small bowel with Barium3, the patients were laid Prone and posterior-anterior (PA) and lateral (LAT) simulation films were taken with and without the SBDS. The areas of the small bowel included in the radiation fields with and without the SBDS were compared. Results : Using the SBDS, the mean small bowel area was reduced by $59\%;on\;PA\;and\;51\%$ on LAT films (P=0.0001). In six Patients (6/55. $11\%$), it was Possible that no small bowel was included within the treatment fields. The mean upward displacement of the most caudal small bowel was 4.8 cm using the SBDS. Only $15\%$ (8/55) of patients treated with the SBDS manifested diarrhea requiring medication. Conclusion : The SBDS is a novel method that can be used to displace the small bowel away from the treatment portal effectively and reduce the radiation therapy morbidities. Compliance with setup is excellent when the SBDS is used.

• 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.31 no.4
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• pp.199-205
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• 2013

Purpose: To assess the clinical efficacy and toxicity of whole pelvic intensity-modulated radiotherapy (WP-IMRT) for high-risk prostate cancer. Materials and Methods: Patients with high-risk prostate cancer treated between 2008 and 2013 were reviewed. The study included patients who had undergone WP-IMRT with image guidance using electronic portal imaging devices and/or cone-beam computed tomography. The endorectal balloon was used in 93% of patients. Patients received either 46 Gy to the whole pelvis plus a boost of up to 76 Gy to the prostate in 2 Gy daily fractions, or 44 Gy to the whole pelvis plus a boost of up to 72.6 Gy to the prostate in 2.2 Gy fractions. Results: The study cohort included 70 patients, of whom 55 (78%) had a Gleason score of 8 to 10 and 50 (71%) had a prostate-specific antigen level > 20 ng/mL. The androgen deprivation therapy was combined in 62 patients. The biochemical failure-free survival rate was 86.7% at 2 years. Acute any grade gastrointestinal (GI) and genitourinary (GU) toxicity rates were 47% and 73%, respectively. The actuarial rate of late grade 2 or worse toxicity at 2 years was 12.9% for GI, and 5.7% for GU with no late grade 4 toxicity. Conclusion: WP-IMRT was well tolerated with no severe acute or late toxicities, resulting in at least similar biochemical control to that of the historic control group with a small field. The long-term efficacy and toxicity will be assessed in the future, and a prospective randomized trial is needed to verify these findings.

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1571-1576
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• 2018

We developed and evaluated an algorithm to calculate the target radiation dose in cancer patients by measuring the transmitted dose during 3D conformal radiation treatment (3D-CRT) treatment. The patient target doses were calculated from the transit dose, which was measured using a glass dosimeter positioned 150 cm from the source. The accuracy of the transit dose algorithm was evaluated using a solid water phantom for five patient treatment plans. We performed transit dose-based patient dose verification during the actual treatment of 34 patients who underwent 3D-CRT. These included 17 patients with breast cancer, 11 with pelvic cancer, and 6 with other cancers. In the solid water phantom study, the difference between the transit dosimetry algorithm with the treatment planning system (TPS) and the measurement was $-0.10{\pm}1.93%$. In the clinical study, this difference was $0.94{\pm}4.13%$ for the patients with 17 breast cancers, $-0.11{\pm}3.50%$ for the eight with rectal cancer, $0.51{\pm}5.10%$ for the four with bone cancer, and $0.91{\pm}3.69%$ for the other five. These results suggest that transit-dosimetry-based in-room patient dose verification is a useful application for 3D-CRT. We expect that this technique will be widely applicable for patient safety in the treatment room through improvements in the transit dosimetry algorithm for complicated treatment techniques (including intensity modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT).

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.2
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• pp.107-112
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• 2007

Purpose: The pelvic phantom was fabricated in the following purposes: (1) Dose verification of IMRT plan using Eclipse planning computer, (2) to study the interface effect at the interface between rectal wall and air. The TLD can be inserted in the pelvic phantom to confirm the dose distribution as well as uncertainty at the interface. Materials and Methods: A pelvic phantom with the dimension of 30 cm diameter, 20 cm height and 20 cm thickness was fabricated to investigate the dose at the rectal wall. The phantom was filled with water and has many features like bladder, rectum, and prostate and seminal vesicle (SV). The rectum is made of 3 cm-dimater plastic pipe, and it cab be blocked by using a plug, and film can be inserted around the rectal wall. The phantom was scanned with Philips Brillance scanner and various organs such as prostate, SV, and rectal wall, and bladder wall were delineated. The treatment parameters used in this study are the same as those used in the protocols in the SNUH. TLD chips are inserted to the phantom to evaluate the dose distribution to the rectal wall (to simulate high dose gradient region), bladder wall and SV (to simulate the high dose region) and 2 spots in anterior surface (to simulate the low dose region). The TLD readings are compared with those of the planning computer (ECLIPSE, Varian, USA). Results: The target TLD doses represented as the prostate and SV show excellent agreements with the doses from the RTP within +/-3%. The rectal wall doses measured at the rectal wall are different from the those of the RTP by -11%. This is in literatures called as an interface effect. The underdosages at the rectal wall is independent of 3 heterogeneity correction algorithm in the Eclipse RTP. Also the low dose regions s represented as surface in this study were within +/-1%. Conclusion: The RTP estimate the dosage very accurately withihn +/-3% in the high dose (SV, or prostate) and low dose region (surface). However, the dosage at the rectal wall differed by as much as 11% (In literatures, the underdosage of 9$\sim$15% were reported). This range of errors occurs at the interface, for example, at the interface between lung and chest wall, or vocal cord. This interface effect is very important in clinical situations, for example, to estimate the NTCP (normal tissue complication probability) and to estimate the limitations of the current RTP system. Monte-carlo-based RTP will handle this issue correctly.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.114-119
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• 2000

Purpose : To evaluate the e지ent and frequency of the inter- and intra-treatment isocenter deviations of the whole pelvis radiation field in using small bowel displacement system (SBDS). Methods and Materials : Using electronic portal imaging device (EPID), 302 postero-anterior 232 lateral portal images were prospectively collected from 11 patients who received pelvic radiation therapy (7 with cervix cancer and 4 with rectal cancer). All patients were treated in prone position with SBDS under the lower abdomen. Five metallic fiducial markers were placed on the image detection unit for the recognition of the isocenter and magnification. After aligning the bony landmarks of the EPID images on those of the reference image, the deviations of the isocenter were measured in right-left (RL), cranio-caudal (CC), and PA directions. Results : The mean inter-treatment deviation of the isocenter in each RL, CC, and PA direction was 1.2 mm ($\pm$ 1.6 mm), 1.0 mm ($\pm$3.0 mm), and 0.9 mm ($\pm$4.4 mm), respectively. Inter-treatment isocenter deviations over 5 mm and 10 mm in RL, CC, and PA direction were 2, 12, 24$\%$, and 0, 0, 5$\%$, respectively. Maximal deviation was detected in PA direction, and was 11.5 mm. The mean intratreatment deviation of the isocenter in RL, CC, and PA direction was 0 mm ($\pm$0.9 mm), 0.1 mm ($\pm$ 1.9mm), and 0 mm ($\pm$1.6 mm), respectively. All intra-treatment isocenter deviations over 5 mm in each direction were 0, 1, 1$\pm$, respectively. Conclusions : As the greatest and the most frequent inter-treatment deviation of the isocenter was along the PA direction, it is recommended to put more generous safety margin toward the PA direction on the lateral fields if clinically acceptable in pelvic radiotherapy with SBDD.