1.Kilovoltage radiotherapy for companion animals: dosimetric comparison of 300 kV, 450 kV, and 6 MV X-ray beams
Jaehyeon SEO ; Jaeman SON ; Yeona CHO ; Nohwon PARK ; Dong Wook KIM ; Jinsung KIM ; Myonggeun YOON
Journal of Veterinary Science 2018;19(4):550-556
Radiotherapy for the treatment of cancer in companion animals is currently administered by using megavoltage X-ray machines. Because these machines are expensive, most animal hospitals do not perform radiotherapy. This study evaluated the ability of relatively inexpensive kilovoltage X-ray machines to treat companion animals. A simulation study based on a commercial treatment-planning system was performed for tumors of the brain (non-infectious meningoencephalitis), nasal cavity (malignant nasal tumors), forefoot (malignant muscular tumors), and abdomen (malignant intestinal tumors). The results of kilovoltage (300 kV and 450 kV) and megavoltage (6 MV) X-ray beams were compared. Whereas the 300 kV and 6 MV X-ray beams provided optimal radiation dose homogeneity and conformity, respectively, for brain tumors, the 6 MV X-rays provided optimal homogeneity and radiation conformity for nasal cavity, forefoot, and abdominal tumors. Although megavoltage X-ray beams provided better radiation dose distribution in most treated animals, the differences between megavoltage and kilovoltage X-ray beams were relatively small. The similar therapeutic effects of the kilovoltage and 6 MV X-ray beams suggest that kilovoltage X-ray beams may be effective alternatives to megavoltage X-ray beams in treating cancers in companion animals.
Abdomen
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Animals
;
Brain
;
Brain Neoplasms
;
Friends
;
Hospitals, Animal
;
Humans
;
Nasal Cavity
;
Pets
;
Radiotherapy
;
Therapeutic Uses
2.Analysis of Once-Daily Thoracic Radiotherapy Dose According to the Underlying Lung Disease in Patients with Limited-Stage Small Cell Lung Cancer Undergoing Concurrent Chemoradiotherapy
Byoung Hyuck KIM ; Joo-Hyun CHUNG ; Jaeman SON ; Suzy KIM ; Hong-Gyun WU ; Hak Jae KIM
Cancer Research and Treatment 2023;55(1):73-82
Purpose:
In the treatment of concurrent chemoradiotherapy (CCRT) in limited-stage small cell lung cancer, the optimal once-daily radiotherapy (RT) dose/fractionation remain unclear although it is the most frequently used. Therefore, this study aimed to compare the treatment outcomes and toxicities of modest dose RT (≤ 54 Gy) with those of standard dose RT (> 54 Gy) and investigate the benefit of the high dose based on patient factors.
Materials and Methods:
Since 2004, our institution has gradually increased the thoracic RT dose. Among the 225 patients who underwent CCRT, 84 patients (37.3%) received > 54 Gy. Because the patients treated with RT > 54 Gy were not randomly assigned, propensity score matching (PSM) was performed.
Results:
The proportion of patients treated with > 54 Gy increased over time (p=0.014). Multivariate analysis revealed that the overall tumor stage and dose > 54 Gy (hazard ratio, 0.65; p=0.029) were independent prognostic factors for overall survival (OS). PSM confirmed that thoracic RT doses of > 54 Gy showed significantly improved progression-free survival (3-year, 42.7% vs. 24.0%; p < 0.001) and OS (3-year, 56.2% vs. 38.5%; p=0.003). Sensitivity analysis also showed that 60 Gy resulted in better survival than 54 Gy. However, in patients with underlying lung disease, OS benefit from > 54 Gy was not observed but considerable rates of severe pulmonary toxicities were observed (p=0.001).
Conclusion
Our analysis supports that the 60 Gy RT dose should be considered in the once-daily regimen of CCRT for limited-stage small cell lung cancer without underlying lung disease, but RT dose > 54 Gy did not seem to benefit for patients with chronic obstructive pulmonary disease or interstitial lung disease. Further study is needed to validate these results.