PET/CT planning during chemoradiotherapy for esophageal cancer

설기호,이정은 대한방사선종양학회 2014 Radiation Oncology Journal Vol.32 No.1

Purpose: To evaluate the usefulness of positron emission tomography/computed tomography (PET/CT) for field modification during radiotherapy in esophageal cancer. Materials and Methods: We conducted a retrospective study on 33 patients that underwent chemoradiotherapy (CRT). Pathologic findings were squamous cell carcinoma in 32 patients and adenocarcinoma in 1 patient. All patients underwent PET/CT scans before and during CRT (after receiving 40 Gy and before a 20 Gy boost dose). Response evaluation was determined by PET/CT using metabolic tumor volume (MTV), total glycolytic activity (TGA), MTV ratio (rMTV) and TGA ratio (rTGA), or determined by CT. rMTV and rTGA were reduction ratio of MTV and TGA between before and during CRT, respectively. Results: Significant decreases in MTV (MTV2.5: mean 70.09%, p < 0.001) and TGA (TGA2.5: mean 79.08%, p < 0.001) were found between before and during CRT. Median rMTV2.5 was 0.299 (range, 0 to 0.98) and median rTGA2.5 was 0.209 (range, 0 to 0.92). During CRT, PET/CT detected newly developed distant metastasis in 1 patient, and this resulted in a treatment strategy change. At a median 4 months (range, 0 to 12 months) after completion of CRT, 8 patients (24.2%) achieved clinically complete response, 11 (33.3%) partial response, 5 (15.2%) stable disease, and 9 (27.3%) disease progression. SUVmax (p = 0.029), rMTV50% (p = 0.016), rMTV75% (p = 0.023) on intra-treatment PET were found to correlate with complete clinical response. Conclusion: PET/CT during CRT can provide additional information useful for radiotherapy planning and offer the potential for tumor response evaluation during CRT. rMTV50% during CRT was found to be a useful predictor of clinical response.

Patterns of failure after the reduced volume approach for elective nodal irradiation in nasopharyngeal carcinoma

설기호,이정은 대한방사선종양학회 2016 Radiation Oncology Journal Vol.34 No.1

Purpose: To evaluate the patterns of nodal failure after radiotherapy (RT) with the reduced volume approach for elective neck nodal irradiation (ENI) in nasopharyngeal carcinoma (NPC). Materials and Methods: Fifty-six NPC patients who underwent definitive chemoradiotherapy with the reduced volume approach for ENI were reviewed. The ENI included retropharyngeal and level II lymph nodes, and only encompassed the echelon inferior to the involved level to eliminate the entire neck irradiation. Patients received either moderate hypofractionated intensitymodulated RT for a total of 72.6 Gy (49.5 Gy to elective nodal areas) or a conventional fractionated three-dimensional conformal RT for a total of 68.4–72 Gy (39.6–45 Gy to elective nodal areas). Patterns of failure, locoregional control, and survival were analyzed. Results: The median follow-up was 38 months (range, 3 to 80 months). The out-of-field nodal failure when omitting ENI was none. Three patients developed neck recurrences (one in-field recurrence in the 72.6 Gy irradiated nodal area and two in the elective irradiated region of 39.6 Gy). Overall disease failure at any site developed in 11 patients (19.6%). Among these, there were six local failures (10.7%), three regional failures (5.4%), and five distant metastases (8.9%). The 3-year locoregional control rate was 87.1%, and the distant failure-free rate was 90.4%; disease-free survival and overall survival at 3 years was 80% and 86.8%, respectively. Conclusion: No patient developed nodal failure in the omitted ENI site. Our investigation has demonstrated that the reduced volume approach for ENI appears to be a safe treatment approach in NPC.

커플제품의 Interactive Love Storytelling 디자인 연구

설기호(Suk Ki-Ho),노보영(No Bo-Young),이선우(Lee Sun-Woo) 한국디자인학회 2007 한국디자인학회 학술발표대회 논문집 Vol.- No.-

Clinical significance of lymph node size in locally advanced cervical cancer treated with concurrent chemoradiotherapy

오진주,설기호,YounSeokChoi,이정원,배진영 영남대학교 의과대학 2019 Yeungnam University Journal of Medicine Vol.36 No.2

Background: This study aimed to assess the in-field lymph node (LN) failure rate according to LN size and to investigate effect of LN size on the survival outcome of patients with locally advanced cervical carcinoma treated with concurrent chemoradiotherapy (CCRT). Methods: A total of 310 patients with locally advanced cervical carcinoma treated with CCRT were enrolled in retrospective study. LN status was evaluated by magnetic resonance imaging. All patients received conventional external beam irradiation and high-dose rate brachytherapy, and concurrent cisplatin-based chemotherapy. In-field LN failure rate according to LN size was analyzed. Results: The median follow-up period was 83 months (range, 3-201 months). In-field LN failure rate in patients with pelvic LN size more than 10 mm was significantly higher than that in patients with pelvic LN size less than 10 mm (p<0.001). A similar finding was observed in the infield para-aortic LN (PALN) failure rate (p=0.024). The pelvic and PALN size (≥10 mm) was a significant prognostic factor of overall-survival (OS) and disease-free survival rate in univariate and multivariate analyses. The OS rate was significantly different between groups according to LN size (<10 mm vs. ≥10 mm). Conclusion: A LN of less than 10 mm in size in an imaging study is controlled by CCRT. On the other hand, in LN of more than 10 mm in size, the in-field LN failure rate increase and the prognosis deteriorate. Therefore, a more aggressive treatment strategy is needed.

Prophylactic extended-field irradiation with concurrent chemotherapy for pelvic lymph node-positive cervical cancer

오진주,설기호,이현주,최윤석,박지영,배진영 대한방사선종양학회 2017 Radiation Oncology Journal Vol.35 No.4

Purpose: This study aimed to evaluate whether prophylactic extended-field pelvic radiotherapy (EF-PRT) yields better results than standard whole pelvic radiotherapy (WPRT) in patients with pelvic lymph node-positive cervical cancer treated with concurrent chemoradiotherapy (CCRT). Materials and Methods: A total of 126 cases of stage IB-IVA cervical cancer that had pelvic lymph node involvement in magnetic resonance imaging and were treated with CCRT between 2000 and 2016 were reviewed. None of the patients had paraaortic lymph node (PALN) metastases. The patients were classified to two groups, namely, those treated with EF-PRT, including prophylactic para-aortic radiotherapy, and those treated only with WPRT. The median dose to the PALN area in patients treated with EF-PRT was 45 Gy. All patients received concurrent cisplatin-based chemotherapy. Results: Overall, 52 and 74 patients underwent EF-PRT and WPRT, respectively. Patient characteristics and irradiated dose were not significantly different, except the dose to the para-aortic area, between the two groups. The median follow-up period was 75.5 months (range, 5 to 195 months). The 10-year cumulative recurrence rate of PALN for EF-PRT vs. WPRT was 6.9% and 10.1% (p = 0.421), respectively. The 10-year disease-free survival and overall survival for EF-PRT vs. WPRT were 69.7% vs. 66.1% (p = 0.748) and 71.7% vs. 72.3% (p = 0.845), respectively. Acute gastrointestinal complications were significantly higher in EF-PRT (n = 21; 40.4%) than WPRT (n = 26; 35.1%) (p = 0.046). Late toxicities were not significantly different in both groups. Conclusion: In this study, prophylactic radiotherapy for PALN does not have an additional benefit in patients with pelvic lymph node-positive cervical cancer treated with CCRT.

Characteristics of Photon Beam through a Handmade Build-Up Modifier as a Substitute of a Bolus

김성준,이승준,문수호,설기호,이정은,Kim, Sung Joon,Lee, Seoung Jun,Moon, Su Ho,Seol, Ki Ho,Lee, Jeong Eun Korean Society of Medical Physics 2014 의학물리 Vol.25 No.4

본 논문에서는 자체 제작된 선량상승영역 변환기(build-up modifier, BM)을 투과하는 high energy photon beam의 심부선량백분율(PDD)을 특성을 측정하고 이 결과를 토대로 BM 산란인자(BM scatter factor, $S_{BM}$)를 계산하였다. 다양한 조건에서 BM scatter가 PDD의 Build-up region에 미치는 영향을 평가하고 BM의 유용성을 알아보는 것이 본 연구의 목적이다. $S_{BM}$는 BM을 사용하지 않은 SFS 30 mm에서 측정된 산란인자의 값을 1로서 정규화 하였다. 가장 큰 SFS 200 mm의 경우, 6 MV 광자선을 사용할 때 $S_{BM}$는 두께에 따라 각각 1.331, 1.519, 1.598, 1.641, 그리고 1.657이었다. 10 MV 광자선에는 각각 1.384, 1.662, 1.825, 1.913, 그리고 2.001이었다. BM의 효과는 bolus의 최대 76% 효율을 가지는 것으로 나타났다. Bolus를 밀착시키기 어려운 특정적 부위에 대해 BM은 그 대안으로써 효과적인 장치가 될 수 있을 것으로 기대된다. We evaluated the effect of scatter on a build-up region based on the measured percent depth dose (PDD) of high-energy photon beams that penetrated a handmade build-up modifier (BM) as a substitute of bolus. BM scatter factors ($S_{BM}$) were calculated based on the PDDs of photon beams that penetrated through the BM. The calculated $S_{BM}$ values were normalized to 1 at the square field side (SFS) of 30 mm without a BM. For the largest SFS (200 mm), the SBM values for a 6-MV beam were 1.331, 1.519, 1.598, 1.641, and 1.657 for the corresponding BM thickness values. For a 10-MV beam, the $S_{BM}$ values were 1.384, 1.662, 1.825, 1.913, and 2.001 for the corresponding BM thickness values. The BM yielded 76% of the bolus efficiency. We expect BM to become useful devices for deep-set patient body parts to which it is difficult to apply a bolus.

Dummy Run of Quality Assurance Program before Prospective Study of Hippocampus-Sparing Whole-Brain Radiotherapy and Simultaneous Integrated Boost for Multiple Brain Metastases from Non-small Cell Lung Cancer: Korean Radiation Oncology Group (KROG) 17-06

정은아,노재명,이규찬,김진희,정원구,서양권,이정애,설기호,우홍균,김연실,노오규,박재원,이동수,이지혜,김영석,박우윤,강민규,조선미,안용찬 대한암학회 2019 Cancer Research and Treatment Vol.51 No.3

Purpose Lung Cancer Subcommittee of Korean Radiation Oncology Group (KROG) has recently launched a prospective clinical trial (KROG 17-06) of hippocampus-sparing whole brain radiotherapy (HS-WBRT) with simultaneous integrated boost (SIB) in treating multiple brain metastases from non-small cell lung cancer. In order to improve trial quality, dummy run studies among the participating institutions were designed. This work reported the results of two-step dummy run procedures of the KROG 17-06 study. Materials and Methods Two steps tested hippocampus contouring variability and radiation therapy planning compliance. In the first step, the variation of the hippocampus delineation was investigated for two representative cases using the Dice similarity coefficients. In the second step, the participating institutions were requested to generate a HS-WBRT with SIB treatment plan for another representative case. The compliance of the treatment plans to the planning protocol was evaluated. Results In the first step, the median Dice similarity coefficients of the hippocampus contours for two other dummy run cases changed from 0.669 (range, 0.073 to 0.712) to 0.690 (range, 0.522 to 0.750) and from 0.291 (range, 0.219 to 0.522) to 0.412 (range, 0.264 to 0.598) after providing the hippocampus contouring feedback. In the second step, with providing additional plan priority and extended dose constraints to the target volumes and normal structures, we observed the improved compliance of the treatment plans to the planning protocol. Conclusion The dummy run studies demonstrated the notable inter-institutional variability in delineating the hippocampus and treatment plan generation, which could be decreased through feedback from the trial center.

2차원 배열형 이온함의 부피효과가 세기조절방사선치료의 선량분포 측정에 미치는 영향

김성준,이승준,박인규,이정은,박신형,설기호,김재철,Kim, Sung Joon,Lee, Seoung Jun,Park, In Kyu,Lee, Jeong Eun,Park, Shin Hyung,Seol, Ki Ho,Kim, Jae Chul 한국의학물리학회 2013 의학물리 Vol.24 No.1

부피효과를 가지는 2차원 배열형 이온함으로부터 측정된 세기조절방사선치료의 선량분포와 부피효과를 가지지 않는 장치로부터 측정된 선량분포를 비교함으로써 이 효과가 측정결과에 미치는 영향에 대해 평가하였다. 조사면 크기에 따라 총 5개의 세기조절방사선치료계획을 5문 조사방식으로 가상의 팬톰에 시행하였다. 선량분포 측정은 매트릭스 팬톰, 빔 영상시스템, 필름 등 총 3가지 측정장치를 이용하였다. 측정된 값은 분석프로그램을 이용하여 전산화치료계획 시스템을 통해 획득된 선량분포와 비교하였다. 비교된 선량분포는 분석프로그램 상에서 상관계수와 감마값을 통해 측정장치의 부피효과 유무에 따른 차이를 분석한 결과 매트릭스 팬톰에서 최대 1.3% 이상으로 나타났다. 매트릭스 팬톰은 조사면의 크기가 작아질수록 내부의 이온함에 의해 부피효과가 커지게 되므로 다른 측정장치에 비해 더 큰 측정오차를 가지는 것으로 판단되었다. We evaluated the influence of volume effect on the measurement of IMRT dose distribution by comparing a 2D-array ion chamber and other dosimeters. Matrix phantom which is a 2D-array ion chamber having volume effect was compared with beam image system and film for the measurement of dose distribution. Five intensity-modulated radiation therapy plans were created using five fields in thevirtual phantom. The measured dose distribution was compared with the calculated one by radiation treatment planning system and analysis program. We evaluated the conformity of dose distribution by calculating correlation coefficients and gamma values. The highest error rate of 1.3% was associated with matrix phantom in which volume effect in small field sizes was substantial.