time of manufacture. \ctsim, however, calculates the \emph{fan beam angle},
\latexonly{$\alpha$,}\latexignore{\emph{alpha},}
from the diameter of the \emph{scan diameter} and the \emph{focal length}
-\latexignore{\\$$\emph{alpha = 2 x asin ( (Sd / 2) / F)}$$\\}
+\latexignore{\\$$\emph{alpha = 2 x asin ( (Sd / 2) / f)}$$\\}
\latexonly{$$\alpha = 2 \sin^{-1} ((s_d / 2) / f)$$}
This is illustrated in figure 2.3.
\begin{figure}
\emph{fan beam angle} is by varying the \emph{focal length} since the
\emph{scan diameter} by the size of the phantom.
+$$s_d = p_d v_R s_R$$
+If $v_r = 1$ and $s_R = 1$, then $s_d = p_d$. Further, $f = f_R v_R (p_d / 2)$
+Plugging these equations into the above equation,
+$$\alpha = 2\,\sin^{-1} \frac{p_d / 2}{f_R (p_d / 2)}$$
+$$\alpha = 2\,\sin^{-1} (1 / f_R)$$
+
+Thus, $\alpha$ depends only upon the \emph{focal length ratio}.
+
\subsubsection{Detector Array Size}
In general, you do not need to be concerned with the detector array
size. It is automatically calculated by \ctsim. The size of the
\usepackage{hyperref}
\input{psbox.tex}
+\includeonly{ctsim-concepts,ctsim-install,ctsim-gui,ctsim-textui,ctsim-web,ctsim-appendix}
\hyphenation{poly-gon-al}
\newcommand{\ctsim}{\texttt{CTSim}}
%\backgroundcolour{255;255;255}\textcolour{0;0;0}% Has an effect in HTML only
\winhelpignore{\title{CTSim 3.0 User Manual}%
\author{Kevin Rosenberg, M.D.}%
-\date{January 2001}%
+\date{February 2001}%
}%
\winhelponly{\title{CTSim 3.0 User Manual}%
\author{by Kevin Rosenberg, M.D.\\$$\image{3cm;3cm}{logo-huge.bmp}$$}%