• Progress in Medical Physics
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• v.34 no.4
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• pp.41-47
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• 2023

Purpose: This study aimed to dosimetrically compare the technique of three-dimensional conformal radiotherapy (3D CRT), which is a traditional prophylactic cranial irradiation method, and the intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) techniques used in the last few decades with the dynamic conformal arc therapy (DCAT) technique. Methods: The 3D CRT, VMAT, IMRT, and DCAT plans were prepared with 25 Gy in 10 fractions in a Monaco planning system. The target volume and the critical organ doses were compared. A comparison of the body V₂, V₅, and V₁₀ doses, monitor unit (MU), and beam on-time values was also performed. Results: In planned target volume of the brain (PTV_Brain), the highest D99 dose value (P<0.001) and the most homogeneous (P=0.049) dose distribution according to the heterogeneity index were obtained using the VMAT technique. In contrast, the lowest values were obtained using the 3D CRT technique in the body V₂, V₅, and V₁₀ doses. The MU values were the lowest when DCAT (P=0.001) was used. These values were 0.34% (P=0.256) lower with the 3D CRT technique, 66% (P=0.001) lower with IMRT, and 72% (P=0.001) lower with VMAT. The beam on-time values were the lowest with the 3D CRT planning (P<0.001), 3.8% (P=0.008) lower than DCAT, 65% (P=0.001) lower than VMAT planning, and 76% (P=0.001) lower than IMRT planning. Conclusions: Without sacrificing the homogeneous dose distribution and the critical organ doses in IMRTs, three to four times less treatment time, less low-dose volume, less leakage radiation, and less radiation scattering could be achieved when the DCAT technique is used similar to conventional methods. In short, DCAT, which is applicable in small target volumes, can also be successfully planned in large target volumes, such as the whole-brain.

• Radiation Oncology Journal
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• v.2 no.2
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• pp.221-228
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• 1984

The recogition that the vast majority of patients with small cell lung cancer have distant metastatic disease at the time of diagnosis lead to the use of systemic chemotherapy and consequent major improvement in survival, but recently evaulated treatment strategies, integration of large field chest irradiation with chemotherapy lead to the improved the local control and relapse free survival in limited SCLC. Therefore, it is logical to combine the two modalities in an effort to maximize the therapeutic effect. Authors performed the combination chemotherapy of CAV (Cyclophosphamide, Adriamycin, an6 Vincristine) and radiotherapy of primary tumor and regional lymphatics with prophylatic cranial irradiation in 42 patients of limited SCLC, from Mar. 1978 to Dec. 1982 Seoul National University Hospital. The results are as follows : 1. CR and PR after 2 cycles chemotherapy is $7\%$ and $43\%$, respectively however, subsequent response to radiotherapy is $38\%$ and $43\%$ in CR and PR. 2. Overall median survival peroid is 8.6 months. 3. 1 year and 2 years survival rate is $46.3\%$ and $20.5\%$, respectively. 4. Incidence of proven brain metastasis is $5\%$.

• Radiation Oncology Journal
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• v.34 no.4
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• pp.313-321
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• 2016

Purpose: Total scalp irradiation (TSI) is a rare but challenging indication. We previously reported that non-coplanar intensity-modulated radiotherapy (IMRT) was superior to coplanar IMRT in organ-at-risk (OAR) protection and target dose distribution. This consecutive treatment planning study compared IMRT with volumetric-modulated arc therapy (VMAT). Materials and Methods: A retrospective treatment plan databank search was performed and 5 patient cases were randomly selected. Cranial imaging was restored from the initial planning computed tomography (CT) and target volumes and OAR were redelineated. For each patients, three treatment plans were calculated (coplanar/non-coplanar IMRT, VMAT; prescribed dose 50 Gy, single dose 2 Gy). Conformity, homogeneity and dose volume histograms were used for plan. Results: VMAT featured the lowest monitor units and the sharpest dose gradient (1.6 Gy/mm). Planning target volume (PTV) coverage and homogeneity was better in VMAT (coverage, 0.95; homogeneity index [HI], 0.118) compared to IMRT (coverage, 0.94; HI, 0.119) but coplanar IMRT produced the most conformal plans (conformity index [CI], 0.43). Minimum PTV dose range was 66.8%-88.4% in coplanar, 77.5%-88.2% in non-coplanar IMRT and 82.8%-90.3% in VMAT. Mean dose to the brain, brain stem, optic system (maximum dose) and lenses were 18.6, 13.2, 9.1, and 5.2 Gy for VMAT, 21.9, 13.4, 14.5, and 6.3 Gy for non-coplanar and 22.8, 16.5, 11.5, and 5.9 Gy for coplanar IMRT. Maximum optic chiasm dose was 7.7, 8.4, and 11.1 Gy (non-coplanar IMRT, VMAT, and coplanar IMRT). Conclusion: Target coverage, homogeneity and OAR protection, was slightly superior in VMAT plans which also produced the sharpest dose gradient towards healthy tissue.

• Journal of Veterinary Clinics
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• v.40 no.2
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• pp.104-112
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• 2023

The change in the position of the abdominal organs due to movement by respiration is one of the reasons behind inaccurate irradiation of organs during radiotherapy (RT). Although studies in human medicine have revealed on the respiratory movements of abdominal organs, there is little information and no reference data for dogs. The purpose of this study was to establish the reference values of abdominal organs movement in various postures using computed tomography (CT), and to compare the movements of organs between dorsal recumbency and ventral, right and left lateral recumbency during respiration. CT images for kidney, adrenal gland, medial iliac lymph node, urinary bladder, gallbladder, liver, stomach, and thoracic and lumbar vertebral body of five beagle dogs were acquired. The movements of organs were evaluated by comparing the end-expiratory and end-inspiratory images. Movements of the organs were evaluated by dividing it into right-to-left, dorsal-to-ventral, and cranial-to-caudal directions. The movements of abdominal organs according to the change in postures and respiration were establish. The movement of the bilateral organs was the least when the organs were in the downward position (p < 0.017). The movement of cranial-to-caudal direction was greater than the movement of the other directions in most of the organs. Data obtained in this study may be useful in selecting the appropriate posture that can reduce the movements of organs to be treated with RT, and the data could be useful for setting the planning target volume to consider the movements of the abdominal organs by respiration.

• Clinical and Experimental Pediatrics
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• v.46 no.6
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• pp.566-571
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• 2003

Purpose : Leukoencephalopathy(LE) is one of the most serious complications in children with hematologic malignancies during the course of treatment. Early recognition is important to reduce the impact and sequelae from LE. We therefore investigated the clinical features of LE following central nervous system(CNS) prophylaxis in children with hematologic malignancies and evaluated the significance of regular check-ups of brain MRI. Methods : We retrospectively reviewed children with hematologic malignancies who had CNS prophylaxis including intrathecal(IT) methotrexate(MTX) and/or cranial irradiation at the Department of Pediatrics, Kyungpook National University Hospital from Oct. 1995 to May 2002. Fifteen cases of acute leukemia and one case of lymphoma who experienced LE following CNS prophylaxis were included in the study. Clinical data were analyzed from the medical records and brain MRIs were reviewed by neuroradiologists. Results : The ages ranged from 1 to 13 years(median age=5.2 years), and the male to female ratio was 3 : 1. The time interval from the beginning of chemotherapy to the time of diagnosis of LE ranged from 2 to 17 months. They all had IT MTX two to 15 times and ten underwent cranial irradiation(1,800 rads). At the time of diagnosis, ten of them had neuropsychiatric symptoms including seizures, personality changes, headache, etc. After the change of treatment modality, four cases showed significant improvement on follow-up MRIs, six cases had no significant changes and two had worsening of LE. Four patients died of infection and bone marrow relapse. Conclusion : CNS prophylaxis with IT therapy and cranial irradiation may cause leukoencephalopathy during the course of treatment. As a result, regular brain MRI check-up is recommended for the early detection and reducing the incidence of LE, along with changes in the treatment modality.

• Radiation Oncology Journal
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• v.14 no.2
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• pp.137-147
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• 1996

Purpose : This report is the result f retrospective analysis for children who received prophylactic cranial irradiation combined with intrathecal chemotherapy. Materials and Methods : Ninety children with ALL who had got bone marrow remission after induction chemotherapy received PCI. All but 3 children were treated with a dose of 1800 cGy as a standard regimen. While the PCI was given, all patients received intrathecal chemotherapy. Results : Nine of 90 patients experienced CNS relapse during the duration of follow-up ranged from 36 to 96 months (median 60 months). Three children experienced BM relapse prior to CNS relapse. Therefore, CNS relapse rate as the first adverse event was $6.7\%$. Median time interval of CNS relapse was 16 months from the first day of hematologic complete remission. Eighty-nine percent of patients who had CNS relapse were associated with hematologic relapse. and $78\%$ of CNS relpase occurred during maintenance chemotherapy (on-therapy relapse). The CNS RFS at 2 and 5 years are $68\%$ and $42\%$, respectively with median of 43 months. The Prognostic factors affecting CNS RFS are initial WBC count (cut-off point of 50,000/ul), FAB subtype and CALGB risk criteria. The DFS at 2 and 5 years are 61 and $39\%$, respectively with median of 34 months. The prognostic factors affecting DFS are initial WBC count (cut-off point of 50,000/ul), FAB subtype, POG and CALGB risk criteria. Conclusions : In our study, $6.7\%$ of CNS relapse rate as a first adverse event was comparable with other studies. Various risk criteria was based on age at diagnosis and initial WBC count such as POG and CALGB criteria, had prognostic significance for CNS RFS and DFS. Prospective randomized trial according to prognostic subgroup based on risk criteria and systematic study about neuropsychologic function for long term survivors, are essential to determine the most effective and least toxic form of CNS prophylaxis.

• Journal of Korean Neurosurgical Society
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• v.30 no.3
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• pp.334-341
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• 2001

Objective : We have currently changed treatment strategies to methotrexate(MTX)-based preirradiation chemotherapy with subsequent planned radiation for the initial therapy of primary central nervous system lymphoma (PCNSL). The aim of this study was to evaluate the results of treating PCNSL with chemotherapy plus radiotherapy (CRT) or radiotherapy(RT) alone. Method and Material : This study involved 10 females and 3 males patients with a mean age of 54.2 years. All patients underwent surgery, open(8 cases) or stereotactic biopsy(5 cases) for histological diagnosis. Eleven tumors were diffuse large B-cell lymphomas. Tumor volume change in the follow-up images and survival time were evaluated in patients treated with CRT and RT alone. In the beginning, two patients received ProMACE-Cytabom chemotherapeutic regimen, but did not complete the course and died of progressive tumor 8 and 9 months after diagnosis, respectively. One patient died at 6 months before chemotherapy. These three were excluded from the survival analysis. Five patients(RT group) completed full courses of cranial irradiation with or without boost. For the current combined modality treatment, high-dose MTXbased chemotherapy(systemic and intrathecal MTX, IV vincristine, and oral procarbazine) followed by whole brain irrdiation to 45Gy to tumor was introduced in 5 patients of CRT group. Result : A complete response was achieved in three of five who received RT only and in all of five who received CRT. All patients in CRT groups are in disease free status at a mean 23 months following therapy. The RT group patients refused any additional salvage therapy at tumor relapse and survived at mean 20 months from diagnosis. The Karnofsky performance status improved in eight of ten patients with treatment. The treatment toxicity included leukoencephalopathy in RT group and severe leukopenia, transient hepatitis, avascular necrosis of femoral head, hearing loss, and amenorrhea in CRT group, respectively. Conclusion : The combined modality therapy of MTX-based chemotherapy plus radiotherapy for PCNSL may enhance tumor response and improve patient survival. The patients who received CRT should be carefully followed up because of the higher risk of treatment-induced late neurotoxicity.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6263-6267
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• 2014

Background: It is standard treatment to combine chemotherapy (CT) and thoracic radiotherapy (TRT) in treating patients with limited stage small cell lung cancer (LS-SCLC). However, optimal timing of TRT is unclear. We here evaluated the survival impact of early versus late TRT in patients with LS-SCLC. Materials and Methods: Follow-up was retrospectively analyzed for seventy consecutive LS-SCLC patients who had successfully completed chemo-TRT between January 2006 and January 2012. Patients received TRT after either 1 to 2 cycles of CT (early TRT) or after 3 to 6 cycles of CT (late TRT). Survival and response rates were evaluated using the Kaplan-Meier method and comparisons were made using the multivariate Cox regression test. Results: Median follow-up was 24 (5 to 57) months. Carboplatin+etoposide was the most frequent induction CT (59%). Median overall, disease free, and metastasis free survivals in all patients were 15 (5 to 57), 5 (0 to 48) and 11 (3 to 57) months respectively. Late TRT was superior to early TRT group in terms of response rate (p=0.05). 3 year overall survival (OS) rates in late versus early TRT groups were 31% versus 17%, respectively (p=0.03). Early TRT (p=0.03), and incomplete response to TRT (p=0.004) were negative predictors of OS. Significant positive prognostic factors for distant metastasis free survival were late TRT (p=0.03), and use of PCI (p=0.01). Use of carboplatin versus cisplatin for induction CT had no significant impact on OS (p=0.634), DFS (p=0.727), and MFS (p=0.309). Conclusions: Late TRT appeared to be superior to early TRT in LS-SCLC treatment in terms of complete response, OS and DMFS. Carboplatin or cisplatin can be combined with etoposide in the induction CT owing to similar survival outcomes.

• Tuberculosis and Respiratory Diseases
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• v.63 no.2
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• pp.154-164
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• 2007

Background: Irinotecan hydrochloride, a topoisomerase I inhibitor, is effective against small-cell lung cancer. Irinotecan also can act as a potential radiation sensitizer along with cisplatin. To evaluate efficacy and toxicity of irinotecan plus cisplatin (IP) with concurrent thoracic radiotherapy, we conducted a phase II study of IP followed by concurrent IP plus hyperfractionated thoracic radiotherapy in patients with previously untreated limited-stage small-cell lung cancer. Methods: Twenty-four patients with previously untreated small-cell lung cancer were enrolled onto the study since November 2004. Irinotecan $60mg/m^2$ was administered intravenously on days 1 and 8 in combination with cisplatin $60mg/m^2$ on day1 every 21 days. From the first day of third cycle, twice-daily thoracic irradiation (total 45 Gy) was given. Prophylactic cranial irradiation was given to the patients who showed complete remission after concurrent chemoradiotherapy. Restaging was done after second and sixth cycle with chest CT and/or bronchosocpy. Results: Up to November 2004, 19 patients were assessable. The median follow-up time was 12.5 months. A total of 99 cycles (median 5.2 cycles per patient) were administered. The actual dose intensity values were cisplatin $19.6mg/m^2$/week and irinotecan $38.2mg/m^2$/week. Among the 19 patients, the objective response rate was 95% (19 patients), with 9 patients (47%) having a complete response (CR). The major grade 3/4 hematological toxicities were neutropenia (35% of cycles), anemia (7% of cycles), thrombocytopenia (7% of cycles). Febrile neutropenia was 4% of cycles. The predominant grade 3/4 non-hematological toxicities was diarrhea (5% of cycles). Toxicities was not significantly different with concurrent administration of irinotecan and cisplatin with radiotherapy, except grade 3/4 radiation esophagitis (10% of patients). No treatment-related deaths were observed. The 1-year and 2-year survival rate of eligible patients was 89% (16/18) and 47% (9/18), respectively. Conclusion: Three-week schedule of irinotecan plus cisplatin followed by concurrent IP plus hyperfractionated thoracic radiotherapy is an effective treatment for limited disease small-cell lung cancer, with acceptable toxicity.

• Journal of Korean Neurosurgical Society
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• v.50 no.6
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• pp.535-537
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• 2011

Recently, combination of surgery and radiation therapy (RT) has been recommended in the treatment of craniopharyngioma. RT could be associated with late complications, including vasculopathy. We report two cases of the moyamoya syndrome seen in children with craniopharyngioma who received RT after surgical resection. Thirty-five patients in pediatric age with craniopharyngioma were surgically treated. Fifteen out of 35 patients underwent surgical resection followed by RT or gamma knife surgery. Two of the 15 were found to have symptoms of transient ischemic attack and were diagnosed as moyamoya syndrome through the cerebral angiography. Age at RT was 4 and 13 years, respectively. The latent period for development of the moyamoya syndrome was 27 months and 3 years, respectively, after RT. The RT dose of both patients was 54 Gy. These two patients received bilateral encephaloduroarteriosynangiosis procedures. We report here these two cases of radiation-induced moyamoya syndrome in pediatric craniopharyngioma. Pediatric patients with craniopharyngioma who received RT should be reminded, during follow-up, about the risk of development of the moyamoya syndrome.