Dosimetric Evaluation of a Set of Specifically Designed Grids for Treating Subcutaneous Superficial Tumor with 6 and 18 MeV Electron Beam External Radiotherapy

Abstract Background: Conventional electron beam radiotherapy used for treating superficial cancer tumors suffers from the disadvantage of low skin sparing effect. Furthermore, increasing electron energy for treating deeper-seated tumors leads to significant increase of skin dose. To overcome this, various grids are recommended for electron beam radiotherapy of subcutaneous tumors. However, appropriate grids are required to be designed for decreasing skin dose while delivering uniform high doses to deep-seated superficial tumors. Our goal was to design, examine and propose appropriate grid(s) for optimum electron beam radiotherapy of subcutaneous tumors with the best skin sparing with 6 and 18 MeV energies.Materials and Methods: Relevant dosimetric characteristics were determined and analyzed for five grids manufactured from dry lead having various cavity diameters (1.5, 2.0, 2.5, 3.0, 3.5 cm) and shielded areas (0.3, 0.4, 0.5, 0.6, 0.7 cm) among the cavities but the same fraction of cavity/open (68%) and shielded/closed (38%) areas under the grid plates. Isodose distributions and dose profiles resulted from the grids were investigated using EDR2 films and MATLAB software. Results: The grids with 2 and 2.5 cm diameter cavities and 0.4 and 0.5 cm shielded areas were the most appropriate grids for 6 and 18 MeV radiotherapy, respectively. With these grids, the 100% PDDs (percentage depth doses) located at 1.25 and 2.5 cm for an open filed (without the grids) were moved down to 1.87 and 5.4 cm for 6 and 18 MeV energies, respectively. Furthermore, the proposed grids provided the least peak to valley dose variations hence the most uniform doses delivered at their relevant depths of treatment. Conclusions: To decrease the skin dose in 6 and 18 MeV electron beam radiotherapy of superficial subcutaneous tumors, various home-made grids were designed and investigated. The most appropriate grids (having 2 and 2.5 cm cavity diameters for 6 and 18 MeV, respectively) provided the optimum dose delivery for superficial subcutaneous tumors locating around 1.5 and 5 cm depth for 6 and 18 MeV energies. Our comprehensive study provides reliable results that could be considered and developed more for a wider range of MeV electron grid therapies in routine clinical practices.

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Influence of β-D-mannuronic acid, as a new member of non-steroidal anti-inflammatory drugs family, on expression pattern of chemokines and their receptors in rheumatoid arthritis

Current Drug Discovery Technologies ◽

10.2174/1570163816666191023103118 ◽

2019 ◽

Vol 16 ◽

Author(s):

Mona Aslani ◽

Arman Ahmadzadeh ◽

Zahra Aghazadeh ◽

Majid Zaki-Dizaji ◽

Laleh Sharifi ◽

...

Keyword(s):

Cell Surface ◽

Mrna Expression ◽

Surface Expression ◽

Phase Iii ◽

Cell Surface Expression ◽

Optimum Dose ◽

High Dose ◽

Mannuronic Acid ◽

Anti Inflammatory ◽

High Doses

Background: : Based on the encouraging results of phase III clinical trial of β-D-mannuronic acid (M2000) (as a new anti-inflammatory drug) in patients with RA, in this study, we aimed to evaluate the effects of this drug on the expression of chemokines and their receptors in PBMCs of RA patients. Methods:: PBMCs of RA patients and healthy controls were separated and the patients' cells were treated with low, moderate and high doses (5, 25 and 50 μg/mL) of M2000 and optimum dose (1 μg/mL) of diclofenac, as a control in RPMI-1640 medium. Real-time PCR was used for evaluating the mRNA expression of CXCR3, CXCR4, CCR2, CCR5 and CCL2/MCP-1. Cell surface expression of CCR2 was investigated using flow cytometry. Results:: CCR5 mRNA expression reduced significantly, after treatment of the patients' cells with all three doses of M2000 and optimum dose of diclofenac. CXCR3 mRNA expression down-regulated significantly followed by treatment of these cells with moderate and high doses of M2000 and optimum dose of diclofenac. CXCR4 mRNA expression declined significantly after treatment of these cells with moderate and high doses of M2000. CCL2 mRNA expression significantly reduced only followed by treatment of these cells with high dose of M2000, whereas, mRNA and cell surface expressions of CCR2 diminished significantly followed by treatment of these cells with high dose of M2000 and optimum dose of diclofenac. Conclusion:: According to our results, M2000 through the down-regulation of chemokines and their receptors may restrict the infiltration of immune cells into the synovium.

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