UNASSIGNED: GRID directs alternating regions of high- and low-dose radiation at @entity5 . A large animal model mimicking the geometries of @entity1 treatments is needed to complement existing rodent systems (eg, microbeam) and clarify the physical and biological attributes of GRID. A pilot study was undertaken in pet @entity235 with spontaneous soft tissue @entity242 to characterize responses to GRID. Subjects were treated with either 20 Gy (3 @entity235 ) or 25 Gy (3 @entity235 ), delivered using 6 MV X- @entity16039 and a commercial GRID collimator. Acute @entity137 and @entity5 responses were assessed 2, 4, and 6 weeks later. Acute Radiation Therapy Oncology Group grade I @entity137 was observed in 3 of the 6 @entity235 ; none experienced a measurable response, per Response Evaluation Criteria in @entity5 . Serum vascular endothelial growth factor, @entity5 @entity39 factor a, and secretory sphingomyelinase were assayed at baseline, 1, 4, 24, and 48 hours after treatment. There was a trend toward platelet-corrected serum vascular endothelial growth factor concentration being lower 1 and 48 hours after GRID than at baseline. There was a significant decrease in secretory sphingomyelinase activity 48 hours after 25 Gy GRID ( P = .03). Serum @entity5 @entity39 factor a was quantified measurable at baseline in 4 of the 6 @entity235 and decreased in each of those subjects at all post-GRID time points. The new information generated by this study includes the observation that high-dose, single fraction application of GRID does not induce measurable reduction in volume of @entity235 soft tissue @entity242 . In contrast to previously published data, these data suggest that GRID may be associated with at least short-term reduction in serum concentration of vascular endothelial growth factor and serum activity of secretory sphingomyelinase. Because GRID can be applied safely, and these @entity5 can be subsequently surgically resected as part of routine veterinary care, pet @entity235 with @entity242 are an appealing model for studying the radiobiologic responses to spatially fractionated radiotherapy.

Outcomes of Spatially Fractionated Radiotherapy (GRID) for Bulky Soft Tissue XXXX in a Large Animal Model.

@entity1 :: ('9606', 'Species') :: ['human'] @entity137 :: ('MESH:D064420', 'Disease') :: ['toxicity', 'skin toxicity'] @entity16039 :: ('255564', 'Species') :: ['rays'] @entity242 :: ('MESH:D012509', 'Disease') :: ['sarcomas'] @entity39 :: ('MESH:D009336', 'Disease') :: ['necrosis'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'Solid Tumors', 'tumors'] @entity235 :: ('9615', 'Species') :: ['canine', 'dogs']
@entity242 :: (MESH:D012509,Disease) :: ['Sarcomas']
