\section{Case: Medical Imaging Workstation}
\label{sec:HMPAcase}

The Medical Imaging workstation was an early large scale Object Oriented product.
Originally intended to become
a re-useable set of toolboxes, it evolved in a family of medical workstations and servers.

\subsection{Product Context}
\label{sec:ProductContext}

Philips Medical Systems is a major player in the medical imaging market.
The main competitors are GE and Siemens.
The Product Creation focus of Philips Medical Systems is modality oriented,
as shown in figure~\ref{fig:PMSorganization}.

\FigureImposeWidth{PMSorganization}{Philips Medical Systems, schematic organization overview.}{\textwidth}

The common technology in conventional X-ray systems is developed by component oriented business groups,
which make generators, tubes, camera's, detectors, et cetera.
The so-called ''System-groups'' have a more clinical focus, they create the clinical oriented systems on the basis of
the common available components.

The non X-ray groups\footnote{A poor name for this collection; The main difference is in the maturity of the modality,
where this group exists from relative ''young'' modalities, 20 a 30 years old.} mainly build large complex
general purpose imaging equipment. The imaging principles in CT and MR are less direct, which means that
an image reconstruction step is required after acquisition to form the viewable images.
Ultra Sound (ATL) is acquired by Philips Medical Systems recently. It is not fully integrated in the organization.
The main markets of Philips Medical Systems are radiology and cardiology, with a spin off to the surgery market.

Traditionally the radiologist makes and interprets images from the human body. A referring physician
requests an examination, the radiologist responds with a report with his findings.
Figure~\ref{fig:RadiologyDrivers} shows a generic set of Radiology drivers.

\FigureImposeWidth{RadiologyDrivers}{Generic drivers of Radiology Departments}{\textwidth}

Philips Medical Systems core is the imaging equipment in the examination rooms of the radiology
department\footnote{equally important core for Philips Medical Systems
is the cardio imaging equipment in the catheterization rooms of
the cardiology department, which is out of the Medical Imaging Workstation scope.}.
The key to useful products is the combined knowledge of application ({\bf what}) and technology ({\bf how}).

\subsection{Historic Phases}
\label{subsec:HistoricPhases}

The development model of Medical Imaging has changed several times. Roughly the phases
in Figure~\ref{fig:HMPAtimelineEasyvision} can be observed. The first phase can best be characterized as
technology development, with poor Market and Application feedback. The next phase overcompensates
this poor feedback by focusing entirely on a product.

\FigureImposeWidth{HMPAtimelineEasyvision}{Phases of Medical Imaging}{\textwidth}

Philips Medical Systems has been striving for re-useable viewing components at least from the late seventies.
This quest is based on the {\it assumption} that the viewing of all Medical Imaging Products is so similar,
that {\it cost reduction} should be possible when a common implementation is used.
The lessons learned during this long struggle have been partially
consolidated in~\cite{www:ProductFamiliesAndGenericAspects}.

The group of people, which started the Common Viewing development, applied a massive amount of
technology innovations, see Figure~\ref{fig:IMItechnologyInnovations}.

\FigureImposeWidth{IMItechnologyInnovations}{Technology innovations by Common Viewing}{\textwidth}

\subsection{Basic Application and Toolboxes}
\label{subsec:BasicApplicationAndToolboxes}

The goal of the common viewing development was to create an extensive set of toolboxes, to be used for viewing in
all imaging products. The developers of the final products had fine-grain access to all toolboxes. This
approach is very flexible and powerful, however the penalty of this flexibility is that the integration is entirely the
burden of the product developer.

\FigureImposeWidth{HMPAswLayers1991}{Idealized layering of SW toolboxes and Basic Application in september 1991}
{\textwidth}

The power of the toolboxes was demonstrated in a {\bf Basic Application}. This basic application was a superset of
all available features and functions. From clinical point of view a senseless product, however a good vehicle to
integrate and to demonstrate.

Figure~\ref{fig:HMPAswLayers1991} shows the idealized layering of the toolboxes and the the Basic Application
in september 1991. the toolbox layer builds upon the Sun computing platform (Workstation, the Sun version of UNIX SunOS
and the Sun windowing environment Sunview). The core of common viewing is the imaging and graphics toolbox, and
the UI gadgets and style.

\subsection{Medical Imaging X-Ray}
\label{subsec:MedicalImagingXray}

\FigureImposeWidth{XRayRoomsOld}{X-ray rooms from examination to reading around 1990}{8cm}

Figure~\ref{fig:XRayRoomsOld} shows the X-ray rooms which are involved from the examination until the reading by
the radiologist. Around 1990 the X-ray system controls were mostly in the control room, where the operator of the system
performed all settings from acquisition setting to printing settings. Some crucial settings can be performed
in the room itself, dependent on the application. The hardcopies were produced as
literal copies of the screen of the monitor. The printer was positioned at some non-obtrusive place.

The consequence of the literal screen copy was that a lot of redundant information is present on the film, such as
patient name, birth date and acquisition settings. On top of that the field of view was supposed to be square or
circular, although the actual field of view is often smaller due to the shutters applied.

\FigureImposeWidth{XRayRoomsPlusPrintServer}{X-ray rooms from examination to reading, when Medical Imaging
is applied as printserver}{8cm}

The economic existence of Medical Imaging X-ray was based in 1992 on  improvements of this printing process. The
patient, examination and acquisition information is orderly shown in one viewport, removing all the redundant
information near the images itself. A further optimization is applied by a {\it fit-to-shutter} formatting.
These 2 steps together reduce the film use by 20\% to 50\%.

\FigureImposeWidth{MedicalImagingFilmComparison}{Comparison of conventional {\it screen copy} based film and
a film produced by Medical Imaging. This case is very favorable for the Medical Imaging approach, typical gain is
20\% to 50\%.}{8cm}

The user actions needed for the printing are reduced as well, by providing print protocols, which perform the repetitive
activities of the printing process. The effectiveness of this automation depends strongly on the application, 
some applications require quite some fine-tuning of the contrast-brightness, or an essential selection step,
which require (human) clinical knowhow.

A prominent sales feature at conferences was the 9-button remote control. The elementary viewing functions, such
as patient/examination selection, next/previous image and contrast/brightness. This remote control lowered the
threshold for clinical personnel, both radiologist as well as technical, enough to catch their interest: The Medical Imaging
was not sold as a disgusting computer or workstations, rather it was positioned as a clinical appliance.

\FigureImposeWidth{HMPAswLayers1992}{Idealized layers of the Medical Imaging R/F software in september 1992}
{\textwidth}

The definition of the Medical Imaging was done by marketing, which described that job as a luxury problem.
Normally heavy negotiations were required to get features in, while this time most of the time marketing wanted
to reduce the (viewing and user interface) feature set, in order to simplify the product.

From software point of view the change from basic application to clinical product was tremendous.
The grey areas in figure~\ref{fig:HMPAswLayers1992} indicate new SW. The amount of code increased from
100~klines to 350~klines of code.

\subsection{Second Concurrent Product: Medical Imaging CT/MR}
\label{subsec:FromSequentialToConcurrent}

Up to 1992 the Medical Imaging organization had a single focus, first on toolboxes, later on Medical Imaging R/F.
In 1993 it was decided to apply the Medical Imaging also on CT and MR.

\FigureImposeWidth{MedicalImagingMPRexample}{Example of Multi Planar Reformatting applied on the spine}{7cm}

The printing functionality of CT and MR scanners improves significantly when Medical Imaging is applied
as printserver.
However the CT and MR applications can benefit also from interactive functionality, more than the X-ray applications.
An clear example is the Multi Planar Reformatting (MPR) functionality, where arbitrary slices are reconstructed
from the volume data set.

\FigureImposeWidth{MedicalImagingCTMRdepartment}{Example of CT and MR department,
where Medical Imaging is deployed}{8cm}

Superficially X-ray viewing looks the same as CT and MR viewing. However the viewing is different in many
subtle ways. A fundamental difference is that X-ray images are {\it projection} images, while CT and MR images
are {\it slices}, which means that CT and MR images have a 3D ''meaning'', which is missing in X-ray images.
The 3D relationship is amongst others used for navigation, a {\it point-and-click} type of user interface: clicking
on a scanogram immediately shows the related slice(s) at that position.

The software was significantly extended, the code size increased from 350~klines to 600~klines.
Note that this is not only an extension with 250~klines, from the original 350~klines roughly half was modified
or removed. In other words a significant amount of refactoring has taken place concurrent with
the application extensions. Figure~\ref{fig:MedicalImagingLayers1994} shows the (idealized) SW structure
at the completion of Medical Imaging CT/MR and the second release of Medical Imaging R/F. Light grey blocks represent
new code, dark grey represents major redesigns.

\FigureImposeWidth{MedicalImagingLayers1994}{Idealized layers of the Medical Imaging software in june 1994}
{\textwidth}

All diagrams~\ref{fig:HMPAswLayers1991}, \ref{fig:HMPAswLayers1992} and \ref{fig:MedicalImagingLayers1994} are
labelled as {\it idealized}. This adjective is used because the actual software structure was less {\it well structured}
than presented by these diagrams. Part of the refactoring in the 1992-1994 time frame was a cleanup,
to obtain well defined dependencies between the software-''groups''. These groups were more fine-grained than
the blocks in these diagrams.

\subsection{Towards Workflow}
\label{sec:TowardsWorkflow}

\FigureImposeWidth{MedicalImagingRadiologyDepartment}{Radiology department as envisioned in 1996}{\textwidth}

\FigureImposeWidth{MedicalImagingHealthcare}{Medical Imaging in health-care workflow perspective, as envisioned in 1996}
{\textwidth}

Medical Imaging R/F and Medical Imaging CT/MR were positioned as {\it modality enhancers}.
The use of these systems enhances the value of the modality. They are used
in the immediate neighborhood of the modality, before the reporting is done.
From sales point of view these Medical Imaging are additional options for a modality sales.

The radiology workflow is much more than the acquisition of the images.
Digitalization of the health-care information flow requires
products which fit in the broader context of radiology and even the diagnostic workflow.
Figures~\ref{fig:MedicalImagingRadiologyDepartment} and~\ref{fig:MedicalImagingHealthcare}
show the increasing context where the workstation technology can be deployed.

\FigureImposeWidth{MedicalImagingLayers1996}{Idealized layers of the Medical Imaging software in 1996}{\textwidth}

The increasing context causes new extensions of the SW building, as shown in
Figure~\ref{fig:MedicalImagingLayers1996}.
