Surface dose measurements and comparison of unflattened and flattened photon beams

The purpose of this study was to evaluate the central axis dose in the build-up region and the surface dose of a 6 MV and 10 MV flattened photon beam (FB) and flattening filter free (FFF) therapeutic photon beam for different square field sizes (FSs) for a Varian Truebeam linear accelerator using parallel-plate ionization chamber and Gafchromic film. Knowledge of dosimetric characteristics in the build-up region and surface dose of the FFF is essential for clinical care. The dose measurements were also obtained empirically using two different commonly used dosimeters: a p-type photon semiconductor dosimeter and a cylindrical ionization chamber. Surface dose increased linearly with FS for both FB and FFF photon beams. The surface dose values of FFF were higher than the FB FSs. The measured surface dose clearly increases with increasing FS. The FFF beams have a modestly higher surface dose in the build-up region than the FB. The dependence of source to skin distance (SSD) is less significant in FFF beams when compared to the flattened beams at extended SSDs

Influence of <i>Eucalyptus</i> Agroforestry on Crop Yields, Soil Properties, and System Economics in Southern Regions of India

Agroforestry benefits farmers, making it a sustainable alternative to monoculture. To create a viable Eucalyptus clone-based agroforestry system, a field experiment was carried out in Tamil Nadu, India. The economics and changes in the soil qualities were evaluated by growing agricultural and horticultural crops, namely pearl millet, sorghum, maize, sesame, small onions, green gram, and red gram, as intercrops under eight-month-old eucalyptus clone trees using a randomised block design in three replications at a spacing of 3 m × 1.5 m. The plots for the intercrops and the eucalyptus clones were kept apart for comparison. Maize showed the greatest drop in plant height during all the phases, including 30 DAS, 60 DAS, and harvest, while small onions showed the least reduction in plant height. Sesame and small onions showed the greatest drop in dry matter production, whereas sorghum showed the least. In terms of the intercrop yield reduction, maize had the biggest reduction and green gram had the lowest. Red gram had the largest crop equivalent yield, whereas maize had the lowest. The volume of the trees was generally increased more favourably by red gram than by green gram. The intercrops had some effects on the nutrients in the soil. Red gram intercropping had the highest levels of EC, soil organic carbon, available soil nitrogen, available soil phosphorus, and available soil potassium, while the sole tree treatment had the lowest levels. Small onions, red gram, and sesame were the crops; tree + small onion, tree + red gram, and tree + sesame were the intercrop combinations with the highest gross income, net income, and B:C in the intercropping treatment alone. Tree + green gram had the highest land equivalent ratio (LER) and the red gram, sesame, and small onion intercrops were shown to be the most profitable. Although the present study supports a complementary relationship, the lack of awareness among farmers of Eucalyptus allelopathy formed the major limitation