\documentclass[12pt,border=5pt]{standalone}
\usepackage{newcent,pstricks,pst-eucl,amsmath,amssymb}
\usepackage{auto-pst-pdf}
\begin{document}
\begin{pspicture}
\psset{PointSymbol=o}
\pstGeonode[PointName=none,PointSymbol=none](2,4){A}(0,0){B}(6,0){C}
\pstCircleABC[PosAngle=180]{A}{B}{C}{O}
\pstGeonode[PosAngle=60](10,2){M}
\pstMiddleAB[PointName=none,PointSymbol=none]{O}{M}{M'}
\pstInterCC[DiameterB=\pstDistAB{O}{M},PosAngleA=45,PosAngleB=-45]{O}{A}{M'}{}{D}{E}
{\psset{nodesepB=-1} \pstLineAB{M}{D} \pstLineAB{M}{E}}
\ncLine{O}{D} \ncLine{O}{E}
\pstInterLL[PointSymbol=none,PosAngle=50,PointNameSep=.55]{O}{M}{D}{E}{H}
\pstRightAngle[RightAngleSize=.2]{D}{H}{M}
\ncLine{O}{M} \ncLine{D}{E}
\end{pspicture}
\end{document}
It produces the following.
But I want to have the following result.
\psdots[dotstyle=Bo](O)(D)(M)(E)