Room: AAPM ePoster Library
Purpose: To study the planned dosimetric differences between static intensity modulated radiotherapy (sIMRT) and volume-modulated arc therapy (VAMT) in patients with esophageal cancer.
Methods: Sixty-five patients with esophageal cancer treated with radiotherapy alone were assigned to sIMRT and VAMT plan, and the dosimetric parameters of the two groups were compared.
Results: Compared with sIMRT, the doses of D99, D95 and Dmean of gross target volume (GTV) under VMRT plan were lower (p < 0.05). The coverage and maximum dose of 99% and 95% of planning target volume (PTV) under VMRT plan were higher (p < 0.05). The coverage of 105% of PTV under VMRT plan was lower (p < 0.05). The conformal index and non-uniform index were similar between the two groups (p > 0.05). In the comparison of organs at risk, the average dose of V20 and V30 of VAMT in both lungs was significantly lower than that of sIMRT (p < 0.05). Spinal cord and heart exposures were similar between the two groups (p > 0.05). The ray numbers of sIMRT and VAMT were 572.33 ± 97.9 and 754.95 ± 177.6 respectively. The ray numbers of sIMRT was 24% lower than that of VAMT (p < 0.05).
Conclusion: Compared with sIMRT, VAMT technology is characterized by ensuring dose distribution in the target area, shortening therapy time and reducing number of rays, improving biological effect and therapeutic efficiency in the target area, and theoretically reducing the probability of secondary cancer. In conclusion, compared with sIMRT, VAMT can improve the dose in the target area, reduce the irradiation time, and may have a better effect in the treatment of esophageal cancer.
Funding Support, Disclosures, and Conflict of Interest: This work was supported by the Key Research and Development Program of Shandong Province (2017GGX201010), Academic Promotion Programme of Shandong First Medical University (2019QL009), Traditional Chinese Medicine Science and Technology Development Plan of Shandong Province (2019-0359), and Taishan Scholars Program of Shandong Province (TS201712065).