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Objective:To evaluate the robustness of fully automated adaptive planning for Ethos online adaptive radiotherapy (ART) based on the intelligent optimization engine (IOE).Methods:Clinical data of 11 stage ⅠB cervical cancer patients admitted to Peking Union Medical College Hospital between June 2021 and June 2022 were retrospectively analyzed. Original planning images and iterative cone-beam computed tomography (iCBCT) images of each radiotherapy treatment were acquired, and all patient data were imported into the Ethos simulator. IOE-based 9-field automatic plan generation was performed for 11 patients using Ethos, and the generated plans were sent to online adaptive radiotherapy simulation to obtain each online adaptive radiotherapy plan (273 fractions in total) and complete the simulated treatment. For comparison, manual plan design was performed based on the images and contoured structures used for online adaptive radiotherapy planning, and the manually plans created with evenly divided 9 fields. Dosimetric parameters, plan complexity parameters, and Mobius quality assurance (QA) pass rates were collected to compare and evaluate the robustness of the online adaptive radiotherapy plan in terms of organs at risk (OAR), target volume dosimetric parameters, and plan complexity by using paired t-test or rank sum test. Results:The online adaptive plan of cervical cancer had comparable planning target volume (PTV) coverage compared to the manual plan. For the clinical target volume (CTV) D 99%, online adaptive plan was significantly higher than the manual plan [(45.93±0.36) vs. (45.32±0.31) Gy, P<0.001]. For hot dose area, the maximum point dose (PTV D max) of adaptive plan was significantly higher than the manual plan [(49.89±1.25) vs. (48.48±0.77) Gy, P<0.001], but the PTV D 1% of adaptive plan was significantly lower than the manual plan [(47.22±0.29) vs. (47.59±0.48) Gy, P<0.001]. There was no statistical difference in the conformal index ( P=0.967). And there was significant difference in the homogeneity index, with same medians and less dispersion in adaptive plan ( P<0.001). For OAR dose, bladder D mean, rectal V 40 Gy, small intestine D mean of adaptive plan was slightly higher than that of the manual plan; the rectal D mean, small intestine D 2 cm3 of the adaptive plan was slightly lower than that of manual plan; dosimetric parameters of right and left femoral heads, spinal cord and bone marrow of the adaptive plan were better than those of manual plan. The adaptive plan had more monitor units (MU) than the manual plan, but the complexity of the adaptive plan was significantly lower than that of the manual plan (0.135±0.012 vs. 0.151±0.015, P<0.001). For Mobius γ pass rate (5%/3 mm), both adaptive and manual plans met clinical requirements. Conclusion:Ethos cervical cancer online adaptive plan, which is based on the IOE engine, demonstrates good robustness and ensures the quality of online adaptive plans generated for each treatment fraction.
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Objective:To evaluate the automatic optimization performance and clinical feasibility of the intelligent optimization engine (IOE) in the Ethos online adaptive radiotherapy platform.Methods:Clinical data of 11 patients with postoperative cervical cancer treated with Halcyon accelerator were retrospectively analyzed. Manual planning was performed for all patients using the 4 full arc volumetric modulated arc therapy (VMAT) (Manual-4Arc) in Eclipse, with a prescription dose of 45 Gy/25F. Patient images and structures were imported into the Ethos simulator, and appropriate clinical goals were added based on clinical requirements. The target coverage was normalized to 95%. Automatic plan generation was conducted using IOE, resulting in 7, 9, and 12 field intensity modulated radiotherapy (IMRT) plans (IMRT-7F、IMRT-9F、IMRT-12F), as well as 2 and 3 arc VMAT plans (VMAT-2Arc、VMAT-3Arc). Dosimetric index comparisons were made between the Manual-4Arc plans and the 5 groups of IOE-generated plans through one-way analysis of variance. Based on the analysis results, Turky post hoc multiple comparisons were performed to evaluate the automatic optimization performance of IOE.Results:In terms of the high dose area, the IMRT-12F plans showed the lowest D 1% for the planning target volume (PTV), and there were significant differences compared to the Manual-4Arc plans ( P=0.004). Regarding target coverage, all groups produced clinical target volume (CTV) plans that met the clinical requirements. Although the Ethos online adaptive plans were normalized during planning, the PTV coverage was slightly insufficient. For organs at risk (OAR) close to the target, such as the bladder, there were significant differences in V 30 Gy, V 40 Gy, and D mean among the 6 groups of plans. The dose ranking for the bladder was generally as follows: IMRT-12F<IMRT-9F<Manual-4Arc<IMRT-7F<VMAT-3Arc<VMAT-2Arc. There were significant statistical differences in V 30 Gy and D mean for the rectum, and the dose ranking was generally consistent with that of the bladder, except for a switch between the IMRT-7F and Manual-4Arc plans. There were no significant differences in rectal V 40 Gy, small intestine D max, and D mean among the 6 groups of plans. For OAR distant from the target, such as the left and right femoral heads, spinal cord, and bone marrow, the dose ranking was generally as follows: IMRT-12F<IMRT-9F<IMRT-7F<VMAT-2Arc<VMAT-3Arc<Manual-4Arc. Conclusion:The plans automatically generated by Ethos IOE in postoperative patients with cervical cancer can achieve similar performance to manual plans, and the automatically generated IMRT-12F and IMRT-9F plans are recommended for clinical use.
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Objective:To explore the feasibility of StereoPhan (SP) phantoms and SRS MapCHECK (SMC) semiconductor matrices in the dose verification of HyperArc (HA) plans for patients with brain metastases (BM).Methods:A total of 16 BM patients who received HA radiotherapy in the Peking Union Medical College Hospital were enrolled in this study. The ion chamber and the SMC semiconductor matrix were inserted into SP phantoms, respectively. The point and planar doses in HA verification plans were measured and compared with the calculated data of the treatment planning system (TPS). The criteria for planar dose γ analysis were set at 2 mm/3%, 2 mm/2%, 1 mm/3%, and 1 mm/2%.Results:The mean deviation of point doses in 16 patients was 1.33%±0.84%. Based on the above criteria, the γ pass rates of planar doses were 99.72%±0.46%, 98.93%±1.32%, 98.85%±1.79%, and 97.13%±3.19%, respectively.Conclusions:SP phantoms and SMC semiconductor matrices are applicable to the dose verification of HA plans for BM patients. The analytical criteria of 3% and 1 mm/2% can be used for verifying point and planar doses, respectively.
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Objective:To analyze the differences in dosimetric quality and plan complexity of volumetric modulated arc therapy (VMAT) plans based on Halcyon 2.0 and Truebeam for different treatment sites of the patients.Methods:Halcyon 2.0 VMAT plans in head & neck, chest, abdomen, and pelvis treatment sites of 49 cases were retrospectively selected and the VMAT plans were re-designed based on Truebeam with the same optimization parameters. The differences in dosimetric metrics and plan complexity between the two types of plans were compared and analyzed. P<0.05 was considered as statistically significant. Results:In terms of PTV, Halcyon 2.0 plans showed better homogeneity index (HI), conformal index (CI) in the head & neck and chest. Besides, Halcyon 2.0 plans yielded better D 98% and CI in the abdomen and better D 2% in the pelvis. For organs at risk (OAR), the D 20% and D mean of bilateral lungs, and D meanof heart for Halcyon 2.0 plans in the chest were lower than those for Truebeam plans (all P<0.05). For the complexity metrics, the median average aperture area variability (AAV) of Halcyon 2.0 plans in the head & neck, abdomen and pelvis were 0.414, 0.425 and 0.432, which were better than 0.385, 0.368 and 0.361 of Truebeam plans in the corresponding sites, respectively. In the abdomen and pelvis, Halcyon 2.0 plans showed better median modulation complexity score (MCS) than Truebeam plans (0.320 vs. 0.268, 0.303 vs. 0.282; both P<0.05). The median small aperture score (SAS) for all plans of Halcyon 2.0 were better than that of Truebeam plans (all P<0.05), and the median plan average beam area (PA) of all plans of Halcyon 2.0 were larger than that of Truebeam plans (all P<0.05). Conclusions:Compared with conventional fractionated VMAT plans based on Halcyon 2.0 and Truebeam, Halcyon 2.0 plans have similar or even better dosimetric quality. However, Halcyon 2.0 plans have lower plan complexity, which makes it an advantage in clinical application.
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AIM: To establish a simple, rapid and accurate high performance liquid chromatographic method (HPLC) for the determination of cyclosporin A (CsA) in human whole blood, and to study the influence of nicotinylmethylamide (Nic) on the pharmacokinetic parameters of cyclosporin A (CsA). METHODS: Whole blood CsA concentrations were measured by HPLC in 18 healthy volunteers administrated single CsA or co administrated Nic. The data of time blood concentrations of CsA were analyzed by 3p97 Program. The analysis of variance and two one sided t test were used to compare the main pharmacokinetic parameters of CsA in the two administrations. RESULTS: C max and AUC 0～∞ of CsA had statistically significance between the single CsA group and co administration of Nic group (P0.05). CONCLUSION: This HPLC method is simple, sensitive and accurate, and is suitable for routine determination of blood CsA levels in human. Nic can improve the absorption of CsA and increase the C max and AUC of CsA, but has no influence on the metabolism of CsA.