ABSTRACT
Background: the dynamic phantom is one of the best tools to study the impact of motion on tumor target delineation and absorbed dose verification during dose delivery
Materials and Methods: this study, a 6-DOF [degrees of freedom] phantom was designed following the stacked serial kinematics and assembled by six commercial motion stages to generate 6-DOF motion, which were RotX [pitch, around X], RotY [roll, around Y], TransZ [anterior-posterior], RotZ [yaw, around Z], TransY [superior-inferior] and TransX [left-right]. Tumor targets were designed by six plastic spheres for the delineation test. Also, an ionization chamber array detector and RW3 solid water were combined to measure the absorbed dose for dose verification tests
Results: the maximum translation speeds for LineX and LineY were 50mm/s and 35mm/s for LineZ, while the maximum rotation speeds for RotX, RotY, RotZ were 5.33° per second, 6degree per second and 15degree per second respectively. Spiral-CT and 4D-CT images acquired in the static and dynamic states successfully showed the influences of tumor motion on target delineation. In the absorbed dose verification, all cases did not pass the gamma test; the pass rate for the 6-DOF motion case was only 34.2% and the pass rates of all other cases were less than 90%
Conclusion: the phantom designed in this study is able to simulate complex tumor motion and can be used to study the influence of tumor motion in radiotherapy
ABSTRACT
The children aged under 5 years from vast African areas badly suffer from falciparum malaria and many of them die of this disease. Therapeutic efficacy of anti-malaria drugs, especially pyrimethamine-sulfadoxine [PS] and chloroquine [CQ] to falciparum malaria is frequently evaluated and reported in recent 10 years. Unfortunately, to date, these widespread materials and researches have not been systematically collected and analyzed. In our study, two investigators were employed to widely and independently gather researches on efficacy of PS vs. CQ mono-therapy of falciparum malaria in children aged below 5 years in unpublished and published databases. Meta-analyses were conducted in categories of PS group and CQ group respectively. Pooled OR of PS vs. CQ was 0.11 [95%CI, 0.05-0.24]. PS showed higher therapeutic efficacy to falciparum malaria in less-than-5-year children than CQ. Random model was chosen to analyze for the heterogeneity existence between different studies. Subgroup analyses were performed, but heterogeneity was still presented. Heterogeneity might be caused by different resistance of falciparum malaria to PS and CQ in different settings. Malaria type associated with parasite species, basic information of PS and CQ, and PS and CQ resistant malaria control measures were demonstrated and discussed respectively in detail in this article