OBJECTIVE: To determine the dosimetric differences between biological and physical functions of equivalent uniform dose (EUD) and dose volume (DV) therapy in patients with phase III non-small cell lung cancer.
METHODS: Four different radiotherapy plans (DV+DV, DV-EUD+DV, EUD+EUD and EUD-DV+EUD) were developed for 15 patients with stage III NSCLC. To study physical function (DV+DV) the target area was optimized by introducing the conditions of biological function optimization, while the organs at risk were optimized by means of physical function (DV-EUD+DV). Biological function optimization (EUD+EUD) was performed for the target area by applying conditions of physical function optimization while biological function optimization (EUD-DV+DV) was conducted for the organs at risk to compare dosimetric parameters among the four groups of treatment plans.
RESULTS: PTV: D2%, D98%, D50%, V105% and Dmax of both the DV-EUD+DV group and EDU-DV+EUD group were the minimum (P<0.05). The minimum and average dose of the EUD+EUD group showed an increasing trend and high-dose area became observable. For homogeneity index (HI), DV-EUD+DV group and EUD-DV+EUD results were compared with the other groups (P<0.05), no significant difference was observed statistically between the DV-EUD+DV group and EUD DV+EUD (P=0.659). With regard to conformability index (CI), the results of the four groups showed no significant difference (P>0.05). For the organs at risk, the mean dose of lung tissue (MLD), V5, V10, V20, V30, heart V30, V40, and Dmean also revealed no significant difference (P>0.05). For the spinal cord, the D1 % of the EUD+EUD group and EUD-DV+EUD groups were significantly different (P<0.05) than the other groups. While no significant difference (P=0.32) was found between the EUD+EUD and EUD-DV+EUD groups. When comparing the number of machine unions (MU) no significant difference was revealed (P>0.05) among the results of the 4 groups.
CONCLUSIONS: The methods featuring optimization of physical and biological functions are effective in improving the uniformity of target area to have better outcome of the treatment. Biological function optimization or the combination of biological and physical function optimization is conducive to significantly reduce the required dose for the spinal cord.

OBJECTIVE: To evaluate the quality of robust stereotactic body proton therapy (RSBPT) plans generated by one-clicking scripting method for patients with lung cancer.
METHODS: Retrospective analysis was performed on fifty lung cancer patients whose plan with robustly stereotactic body radiation therapy (SBRT). Thirty out of fifty patients were used for training to build a regression model, based on robust SBRT reference doses, to predict EUD values of ROIs for robust SBPT planning. Thereafter, robust SBPT plans with both automated EUD-Based mimicking (Automated Robust Proton ARP) and manual (Manual Robust Proton MRP) methods were evaluated in the remaining 20 patients. Plans were compared in terms of dosimetric parameters and planning time.
RESULTS: A statistically significantly improvement in target dose fall off was observed for ARP plans compare to MRP plans (Dose fall off: 135 for MRP and 88 for ARP, p < 0.01), while no differences in target coverage and conformity. A statistically significantly reduce in normal lung tissue were observed for ARP plans compare to MRP plans (Lung [Dmean cGy (RBE)]: MRP: 478 vs. ARP: 351, p < 0.01; Lung [V5Gy (RBE) (%)]: MRP: 16.1 vs. ARP: 12.1, p < 0.01; Lung [V20Gy (RBE) (%)]: MRP: 8.5 vs. ARP: 6.8, p < 0.01). Planning time was reduced for ARP plans compare to MRP plans (optimization time: 12 min for MRP vs. 8 min for ARP; total plan time: 23 min for MRP vs. 18 min for ARP).
CONCLUSIONS: The automated robust SBPT plans using EUD-Based mimicking of SBRT reference dose improve target dose fall off, reduced the radiation doses to the lungs, reduce planning time, which might be beneficial for patient with lung cancer in clinical.

The study aimed to develop a novel dose conversion platform by improving linear-quadratic (LQ) model to more accurately describe radiation response for high fraction/acute doses. This article modified the LQ model via piecewise fitting the biological dose curve using different fractionated dose and optimizing the consistency between mathematical model and experimental data to gain a more reasonable transform. That mathematical development of the LQ model further amended certain deviations of various cell curves with high doses and implied the rationality of the present model at low dose range. The modified biologically effective dose model that solved the dilemma of inaccurate LQ model had been used in comparing between hypofractionated and conventional fractioned dose. It has been verified that the calculated values are similar in the treatment of same efficacy, no matter what α/β is, and provided a more rational explanation for significant differences among various hypofractionations. The equivalent uniform dose based on the subsection function could represent arbitrary inhomogeneous dose distributions including high-dose fractions, providing a foundation for the implementation of detailed evaluation of different cell dose effects.