geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

A fast double template convolution isocenter evaluation algorithm with subpixel accuracy


, : A fast double template convolution isocenter evaluation algorithm with subpixel accuracy. Medical Physics 38(1): 223-227

To design a fast Winston Lutz (fWL) algorithm for accurate analysis of radiation isocenter from images without edge detection or center of mass calculations. An algorithm has been developed to implement the Winston Lutz test for mechanical/ radiation isocenter agreement using an electronic portal imaging device (EPID). The algorithm detects the position of the radiation shadow of a tungsten ball within a stereotactic cone. The fWL algorithm employs a double convolution to independently find the position of the sphere and cone centers. Subpixel estimation is used to achieve high accuracy. Results of the algorithm were compared to (1) a human observer with template guidance and (2) an edge detection/center of mass (edCOM) algorithm. Testing was performed with high resolution (0.05 mm/px, film) and low resolution (0.78 mm/px, EPID) image sets. Sphere and cone center relative positions were calculated with the fWL algorithm for high resolution test images with an accuracy of 0.002 +/- 0.061 mm compared to 0.042 +/- 0.294 mm for the human observer, and 0.003 +/- 0.038 mm for the edCOM algorithm. The fWL algorithm required 0.01 s per image compared to 5 s for the edCOM algorithm and 20 s for the human observer. For lower resolution images the fWL algorithm localized the centers with an accuracy of 0.083 +/- 0.12 mm compared to 0.03 +/- 0.5514 mm for the edCOM algorithm. A fast (subsecond) subpixel algorithm has been developed that can accurately determine the center locations of the ball and cone in Winston Lutz test images without edge detection or COM calculations.

US$19.90

PMID: 21361190

DOI: 10.1118/1.3524227


Other references

Balon, E.K.; Holcik, J., 1964: New for Poland lampreys and fishes from the Danube basin (Black Orava). Fragmenta Faunistica Mus Zool Polon, 11: 189-206

Ross, S.D.; Kern, J.A.; Gangemi, J.J.; S.L.urent, C.R.; Shockey, K.S.; Kron, I.L.; Tribble, C.G., 2000: Hypothermic retrograde venous perfusion with adenosine cools the spinal cord and reduces the risk of paraplegia after thoracic aortic clamping. Objective: We evaluated the utility of retrograde venous perfusion to cool the spinal cord and protect neurologic function during aortic clamping. We hypothesized that hypothermic adenosine would preserve the spinal cord during ischemia. Methods:...

Freeman, G.J.; Gribben, J.G.; Boussiotis, V.A.; Ng, J.W.; Restivo, V.A.; Lombard, L.A.; Gray, G.S.; Nadler, L.M., 1993: Cloning of B7-2: a CTLA-4 counter-receptor that costimulates human T cell proliferation. Although presentation of antigen to the T cell receptor is necessary for the initiation of an immune response, additional molecules expressed on antigen-presenting cells deliver essential costimulatory signals. T cell activation, in the absence of...

Telisinghe, L.; Waite, T.D.; Gobin, M.; Ronveaux, O.; Fernandez, K.; Stuart, J.M.; Scholten, R.J.P.M., 2015: Chemoprophylaxis and vaccination in preventing subsequent cases of meningococcal disease in household contacts of a case of meningococcal disease: a systematic review. Household contacts of an index case of invasive meningococcal disease (IMD) are at increased risk of acquiring disease. In revising WHO guidance on IMD in sub-Saharan Africa, a systematic review was undertaken to assess the effect of chemoprophyla...

Gates, J.D., 1994: Delayed hemorrhage with free rupture complicating the nonsurgical management of blunt hepatic trauma: a case report and review of the literature. The nonsurgical approach for the management of blunt hepatic injuries is appropriate for a select subset of patients. An acceptable number of complications of the biliary tract and intraparenchymal hematomas have been reported. Delayed hepatic hem...

Kramer, K.M.; Birney, E.C., 2001: Effect of light intensity on activity patterns of Patagonian leaf-eared mice, Phyllotis xanthopygus. The effect of light intensity on activity was investigated in a study of captive leaf-eared mice, Phyllotis xanthopygus. This nocturnal mouse lives in rocky outcrops but forages in open areas with little vegetative cover. Primary predators are rap...

Sobolev Nikolai V.; Taylor L.A.; Logvinova A.M.; Seryotkin Y.V.; Koptil V.I.; Yefimova E.S., 2002: First report of majoritic-garnet diamond inclusions from Yakutian kimberlites. Eos, Transactions, American Geophysical Union 83(47, Suppl

Brown, E.J.; Hosea, S.W.; Frank, M.M., 1983: The role of antibody and complement in the reticuloendothelial clearance of pneumococci from the bloodstream. An experimental model of pneumococcal bacteremia in guinea pigs has been developed. By use of this model, complement has been shown to play a critical role in clearance of Streptococcus pneumoniae from the bloodstream and in survival of guinea pig...

Mostardi, R.E.; Shapley, A.E.; Nestor, D.B.; Steidel, C.C.; Reddy, N.A.; Trainor, R.F., 2013: Narrowband Lyman-Continuum Imaging of Galaxies at z ~ 285. We present results from a survey for z~2.85 Lyman-Continuum (LyC) emission inthe HS1549+1933 field and place constraints on the amount of ionizing radiationescaping from star-forming galaxies. Using a custom narrowband filter (NB3420)tuned to wave...

Janik, J.M.; Robinson, E.O.N.ill; Shen, J.; Callahan, P., 1997: Effects of age and gender on the AII-induced stimulation of prolactin release and inositol phosphate accumulation in rat anterior pituitary cells in vitro. The stimulatory effects of Angiotensin II (AII) on prolactin secretion and inositol phosphate accumulation were examined in dispersed anterior pituitary cells collected from young (3-4 month), mature (7-8 month) and old (18-20 month) mate and fema...