
			XSPECT  vers 3.5b

Summary:

	XSPECT is a collection of programs for modeling x-ray 
	production, attenuation, and detection for radiographic
	imaging systems. The spectral distribution of the source 
	can be generated using XSPECT's semiempirical models for
	electron target tubes or can be input from 
	previously stored tabular data.  Attenuation is computed
	from libraries having data on material composition, _materials,
	and data on interaction coefficients, _database. New materials 
	can be easily added to the material library. Utility programs
	allow the spectra to be integrated or determination of the
	exposure(i.e. air ionization). From precomputed tables of
	signal and noise detection efficiency, the response of a 
	particular detector system can be computed.
	
	Documentation for each program is in the _doc directory along
	with supplemental documentation regarding the use of the 
	tcl (tclsh) for running xspect programs 
	and the use of gnuplot for plotting results.  
	A standard file format is used to describe the spectral 
	distribution of x-rays at various positions in the model.  
	This format, explained in spect.tmp.txt, allows the spectral 
	distribution to be expressed in different units.

	The XSPECT version 3.5c programs have evolved from software
	developments begun in 1983 in the X-ray Imaging Research Laboratory
	at Henry Ford Health System. Contributions to this effort have
	come from Michael Flynn, Scott Wilderman, Zhiheng Ge, James Pipe,
	Sean Hames, chip dodge and numerous users who have contributed
        useful suggestions. Particular recognition must be given to the
	efforts of Scott Wilderman who wrote the majority of the code
	and assembled the database of interaction cross sections.

Platform:

	XSPECT was originally developed using a Unix Platform.
	The Radiation Imaging Computational Lab was originally offered
	on Sun Unix systems using the c-shell script lanquage (csh).
	The use of tcl/tk on Unix system was subsequently introduced.
	In 2004, student were offered the option of using either Windows
	or Unix. Beginning in 2005, support for Unix systems was dropped.
	If there is a particular interest, the Unix course material from
	2004 is available. Contact mikef@rad.hfh.edu for information
	on obtaining this material.

Usage:

	To use the XSPECT programs the appropriate links to the libraries
	and the executable programs must be established. The introductory
	modules for a computational laboratory course which uses XSPECT
	contain specific information on setting up these links.
	The subsequent course modules on sources, image formation, and image
	detection contain a multitude of examples that may be useful
	in learning how to effectively use these programs.

Models:

	A model for a particular problem will usually be developed
	by writing a shell script to invoke the particular XSPECT
	programs to be used. Within the _templates or _tcl directories are 
	short shell commands specific to each of the XSPECT programs. 
	When starting a model for a new problem, it is 
	recommended that a new working directory be established first. 
	Within that directory, a shell script for the model can 
	then be created by either combining the short script templates
	or using the procedures in _tcl as necessary. 
 
	For combining script templates on a Unix system,
	the concatonate command, cat, can be used;

-U->	cat link.tcl spectgen.txt atten.txt sr2cm.txt mR.txt ... > model.tcl

	For combining script templates on a Windows system, utilities
	in the TclLib can be used from the command window;

-W->	package require tclutil
	set files "link.tcl spectgen.txt atten.txt sr2cm.txt mR.txt ..."
	::fileutil::writeFile model.tcl [::fileutil::cat $files]

	The script templates for a problem might accomplishe the following;

		link.tcl:	establishes the path within the xspect directory.
		spectgen.txt:	generates the x-ray spectral distribution.
		atten.txt:	accounts for tube filtration.
		sr2cm.txt:	changes units for the object distance.
		mR.txt:		computes the input exposure to the object.
		atten.txt:	accounts for object filtration.
		cm2cm.txt:	changes distance to the detector.
		mR.txt:		computes the input exposure to the detector.
		detect.txt	computes the detector signal and noise.

	Each of the small script templates has only dummy arguments for the 
	required variables. Once the model.tcl file has been set up, the
	user must edit this file to specify such things as kVp, filtration
	material, object thickness, etc.  Additionally the user may
	want to put program loops in the model.csh to compute results
	while a parameter is varied.

	Similar methods are employed when using the tcl procedures.
	Because of the more advanced script language, the tcl routines
	are somewhat more compact and simpler to use when setting up
	a particular model. Additionally, the tk extensions to tcl allow
	graphic windows to be easily assembled and used to control scripts.

Distribution:

	The standard distribution for XSPECT 3.5b  will have the following 
	directories;

	_database			interaction data files
	_detectors			detector response files
	_doseTables			Tables to compute mean mGy dose
	_materials			material definition files
	_xspect3.5
		_bin			executable files
		_doc			documentation files
		_Examples		laboratory solution examples
		_Models			model files from projects
		_tcl			Tcl/Tk procedures
		_templates		short tcl script templates

Whats next?

	Considerable work has been done on a major upgrade to version 4.0.
	This includes all new radiation interaction data and new models
	for x-ray spectral estimation. The new software will be much more
	suitable for optimization problems with several variables.
	This release is expected to be finished by end of 2013.

For further information contact:

	Michael J. Flynn, PhD.          mikef@rad.hfh.edu
	^^^^^^^^^^^^^^^^^^^^^^^         mikef@engin.umich.edu

	X-ray Imaging Res. Lab.         Adj. Professor	
	Radiology Research (2F)         Nucl. Engr. & Radiological Science	
	Henry Ford Health System        University of Michigan

	  1 Ford Place               313-874-4483
	  Detroit, MI, 48202         313-874-4494 (FAX)

MJF 2/18/96
    3/02/03
    1/17/05
    1/09/11
    1/11/13

