scholarly journals Characteristics and limitations of a secondary dose check software for VMAT plan calculation

2021 ◽  
Vol 22 (3) ◽  
pp. 216-223
Author(s):  
Andrew J. Shepard ◽  
Sean P. Frigo
Keyword(s):  
2020 ◽  
Vol 21 (1) ◽  
pp. 95-102
Author(s):  
Michael T. Prusator ◽  
Tianyu Zhao ◽  
James A. Kavanaugh ◽  
Lakshmi Santanam ◽  
Joe Dise ◽  
...  

2021 ◽  
Author(s):  
John Baines ◽  
Ariadne Shoobridge

Abstract During the adaptive workflow associated with MRgRT, a secondary dose calculation is required and MU2net (DOSIsoft, France) is one commercial option. The suitability of MU2net to be used in conjunction with the online Monaco treatment planning system of the Elekta Unity (Elekta AB, Stockholm, Sweden), is evaluated in this work. Monaco and MU2net point doses are compared for various fields on and off axis and at different SSDs. To investigate the comparative effects of attenuation due to the cryostat, couch and posterior coil, measured, MU2net and Monaco dose outputs at the isocentre, as a function of gantry angle, were compared. Point doses for the beams of nine step and shoot IMRT (SSIMRT) test plans (courtesy Elekta) were calculated with Monaco v5.4 and compared to corresponding doses computed with MU2net. In addition, Monaco v5.4 and MU2net point doses were compared for 1552 beams treated on the Unity at our facility. For the on-axis fields investigated the agreement between MU2net and measured data is acceptable. MU2net and Monaco point doses for the Elekta SSIMRT test plans were within ± 5.0 % and ± 6.4 % for beams delivered from gantry zero and at planned beam angles, respectively. For the 1552 beams delivered approximately 80.0 % of MU2net and Monaco point doses agree within ± 5.0 %, therefore it is recommended to correlate MU2net Dose Reference Points (DRPs )with pre and post treatment dosimetry verification. Computational accuracy of MU2net could be enhanced with improved modelling of attenuation due to the couch, cryostat and posterior MR imaging coil.


1997 ◽  
Vol 70 (1) ◽  
pp. 441-444 ◽  
Author(s):  
P.J. Binns ◽  
J.H. Hough

Parasitology ◽  
1988 ◽  
Vol 97 (1) ◽  
pp. 89-99 ◽  
Author(s):  
H. Watson ◽  
D. L. Lee ◽  
P. J. Hudson

SUMMARYThe course of primary and secondary infections with Trichostrongylus tenuis in the domestic chicken was investigated. Primary infections were established after the administration of single and trickle doses of infective-stage larvae. The worm burden in the caeca was highest after a single dose of 500 infective-stage larvae; this gave a mean of 87 nematodes per bird on days 8–9 of infection, 20 nematodes on day 14 and 0 on day 28 of infection. Following trickle doses of 60, 100, 200, 300, 400 or 500 infective-stage larvae, there was a rise and then a fall in nematode egg output in all groups. In chickens given a primary dose of 500 infective-stage larvae followed 30 days later by a single secondary dose of 500 infective-stage larvae, the mean worm burden during the secondary infection rose to 57 nematodes on day 9 of infection and then fell rapidly to 18 nematodes on day 15 and to 2 on day 30. Scanning electron microscopy showed changes in the caeca of infected birds, with the caecal surface being covered in a layer of mucus from 12 days after infection. Balls of blood-stained mucus containing nematodes were observed in the caecal droppings from day 9 of infection onwards. It is concluded that chickens rapidly expel an established infection of T. tenuis, unlike the normal host, the red grouse.


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