Inr. J. Radumon Oncology Btol. Phys Vol Pruned m the U S A. All nghts reserved
22, pp. 147-157 Copyright
0360.3016/92 $5 00 + .oO 0 1991 Pergamon Press plc
??Technical Innovations and Notes
RADIATION T. W.
ONCOLOGY
ZUSAG,
M.D.,‘*
RESIDENTS’
S. MCDONALD,
J. A. PURDY, PH.D.’
COMPUTER
M.B.,
CH.B.,~
A.
WORKSTATION MILLER, B.A.,2
AND P. RUBIN, M.D.2
‘Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO; and * University of Rochester School of Medicine, Rochester, NY We are investigating the feasibility of using the Macintosh computer as a workstation platform for radiation oncology residents because of its ease of use, graphics capability, and low cost. HyperCard was chosen as the programming environment because it easily mixes graphics, text, and control functions in an integrated screen display. Furthermore, it results in a system that can be relatively easily extended and customized by individual users with varying degrees of computer skills. We have developed several software modules in order to test the ability of this environment to support the demands of such a workstation. Modules created thus far include various clinical physics aids and tutorials, treatment planning guides, oncology databases, and others. The software runs on all Macintosh configurations, but calculation speeds are improved when a 68020 or greater processor is used. In general, we have been pleased with the implementation thus far. Graphics display capability is good, but design and entry of graphics have proved labor-intensive. Searching is fast and text is easily entered and manipulated. Finished modules can be customized with minimal computer training, but implementing complex new functions requires familiarity with HyperCard’s programming language. New modules, once developed, are easily integrated into the workstation universe, suggesting that cooperative development of the workstation by multiple contributors is realistically achievable. Computer workstation,
Computer graphics,
Education,
Resident training, Dosimetry,
HyperCard.
played roles. Text displays present large volumes of information rapidly but command-line interfaces can intimidate novices, particularly those with little extra time for computer training. Illustrations to strengthen the impact and improve comprehension of displayed data often required additional hardware or were implemented with crude, character-based pseudo-graphics (1). The development of icon-based windowing operating systems and hardware optimized for graphics has improved the usefulness and accessibility of computers for the casual user (6). In a field such as radiation oncology, with its technical and 3-dimensional spatial orientation, a graphicsbased personal workstation for clinical and educational applications might prove very useful. Possible contents or functions of such a workstation might include anatomy or CT atlases, treatment planning guides, procedure manuals, dosimetric calculations, tutorials, literature references, personal files, and so on. There have been prior published reports of microcomputer use in radiation oncology, but these have been primitive systems with limited scope, such as spreadsheets for dosimetric cal-
INTRODUCTION
There are many uses to which a computer might be put within the context of a radiation oncology residency program. Information storage, interactive tutorials, on-line library searching, and clerical functions are frequently mentioned. Computers have been used in such roles in the past, typically mainframe or minicomputers running elaborate custom software, but the systems were costly, inflexible, and not widely used. One of the advantages of computerized information sets, namely, the ability to customize the contents and structure according to the needs of the individual user, was rarely realized with these large systems. Powerful and relatively inexpensive microcomputers, which promised a revolution in “personal” computing, have been available for many years but few residents use them much or very efficiently. Several factors may be responsible for the low level of use. Inaccessible user interfaces, complex setup, scarcity of appropriate and useful software, and lack of programming skills have probably all
Presented at the 32nd Annual Meeting of the American Society for Therapeutic Radiology and Oncology, October 1990. *Dr. Zusag is now at the Department of Therapeutic Radiology, Rush Presbyterian St. Luke’s Medical Center, 1753 W. Congress Parkway, Chicago, IL 60612.
Reprint requests to: James A. Purdy, Washington School of Medicine, 510 So. Kingshighway Blvd., MO 63110. Accepted for publication 24 May 1991. 147
University St. Louis,
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Cervix
Volume 22, Number 1, 1992
inFo
Cancer of the Cervix
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Tom Zusag, MD
MII? trecpolicies
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Personal stacks
Fig. 1. The index card of a treatment planning guide. All of the stacks have index cards with a similar format. Five buttons in the middle allow branching to basic categories of information within the stack. Clicking on the title field hides it to reveal the index of all cards in the stack. The buttons in the right column are for utilities such as searching
or stack repair, or for branching to other workstation areas or to outside stacks, such as the HyperCard “Home” stack.
culations (7, 9), or drill programs for physics training (1). No integrated multipurpose software has been described, either mainframe or desktop-based.
METHODS
AND MATERIALS
Hardware Our goal is to develop a functional, compact, low-cost workstation. The ideal system should be universally available, powerful, easy to use, and expandable and configurable by the end user. Although intended primarily for radiation therapy residents, it has become apparent that such a system could be a desirable addition to the clinic. With residents as the target audience, however, cost becomes an important issue. At present, this precludes requiring the use of specialized hardware such as color displays or videodisk storage devices (4). Nevertheless, one would want to preserve expansion options for those with larger budgets, or for technical advances in the future. Several microcomputers from various manufacturers have become available in recent years that employ, or can be used with, graphics interfaces. We chose the Macintosh* as the basic hardware device. It is a personal computer based upon the Motorola 68000 processor series. It *Macintosh
is a trademark of Apple Computer.
features an icon-based operating system, and is simple to configure and use, relatively inexpensive, and widely available. Graphics display, mouse, printer and hard disk interfaces, and digitized audio capability are standard on all models. The small monochrome screen used on the basic models cannot display color or continuous-tone images but is capable of black-and-white bitmapped graphics of a quality sufficient for many applications. The various software packages all have a similar look and feel and share a common set of core commands for basic operations. This makes unfamiliar programs less intimidating and facilitates their introduction without extensive retraining. Software that runs on basic machines is upward compatible without modification on more advanced models, so future expansion and more elaborate systems are possible for those with larger budgets. The system described in this article will run on any Macintosh with 1 megabyte or more of memory and at least 2-800k floppy drives or a hard disk drive. Programming environment We wanted the system to be modifiable by end users whose computer experience may vary widely. We intend to distribute it freely, and ultimately we would like to see
Radiation oncology residents’ workstation ??T. W. ZUSAGet al.
Cervix
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ports
To
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Added for common iliac nodes standard portal Added for vaginal exmsion
Mlf? treatment
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Nodal drainage
Return
Fig. 2. A typical field diagram from a treatment planning guide. Multiple such cards may be included within a given stack. Buttons at the top left branch back to other clinical stacks or to the title card, while those at the bottom link to related topics.
this project evolve as a group effort within the radiation oncology community. With this in mind, we chose HyperCard? as the programming environment. HyperCard is part of the standard system software of the Macintosh. Although it has resisted brief definitions, it can be considered a graphics-and-text information storage and authoring system (3, 4, 8, 10). It operates on a “stack of cards” metaphor. Each screen display (“card”) in the file (“stack”) contains text fields, graphics and various controls (“buttons”). Buttons are areas on screen containing a word and/or a small graphic called an icon intended to indicate their function. They are activated by a click of the mouse, and can be configured to perform calculations, manipulate data, or navigate to any other card in the same or another stack. Stacks contain data as well as the programming that manipulates the data, and the structure is extensible: data, functions, and controls can be added or altered at will. HyperCard features a high-level English-like programming language with a full array of string, boolean, and mathematical operators. It also has built-in clock and calendar functions, and routines to handle input/output, sound, and graphics. Programs are called scripts and consist of one or more subroutines or handlers. Scripts have tHypercard is a trademark of Apple Computer.
the ability to call external subprograms written in compiled languages such as Pascal and C for specialized needs. Fairly complex scripts are possible; nevertheless, simple functions such as linking two screens for serial display may be implemented without any programming skills. Multiple scripts may be embedded into the stacks upon which they operate. A script may be associated with any button, field, or card in the stack, and its routines will be activated when a specific triggering event is detected. Examples of events are clicks of the mouse button, changes to text fields, and so forth. All of the programming consists of scripts and external subprograms. The scripts in the project are more than 99% our own work; however, scripts or techniques from public domain sources were adapted if they could improve certain functions. Included in this fashion are several external subroutines used for statistical functions, file manipulation, and so on. Some of these came from Apple and some from other educational sources. No commercial material or material that requires licensing was used. Data Raw data for the project stacks were abstracted from various private and published sources, such as lecture
I. .I. Radiation
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Composioedistribution
Volume 22, Number
Inilial fields: 5000 cGy vhole brain
1, 1992
Boost fields: 1500 cGy weighed 2:l
Show info Compare to unilateral
tumor
11 Position -_ __
.._._.
.I_
.
Fig. 3. A sample isodose card from a treatment planning guide. The user can compare this to other treatment schemes and tumor configurations by clicking on the buttons shown. Alternate distributions on other cards are aligned so that differences are easily seen as one image dissolves into another. Other buttons give detailed discussion of the pros and cons of a given technique, or permit navigation to cards which give setup position and anatomical field orientation.
notes, presentations, departmental treatment policy manuals, and clinical data books. Illustrations were hand-drawn on screen using HyperCard’s built-in tools, digitized from existing artwork using a flatbed scannet+, or imported from public domain files. Scanned material often required extensive retouching to clean up artifacts produced in the process of digitizing continuous-tone images or line drawings. IMPLEMENTATION About a dozen stacks have been created to date, containing in aggregate over 2.50 cards. They can be grouped into three functional categories: dosimetry and physics, clinical information, and personal productivity aids. Each of these categories is represented in a central “Home” stack by one or more screens (not shown) containing buttons for navigating out to the various stacks or cards associated with that category. Users can navigate anywhere in the workstation universe with a maximum of three mouse clicks, and can easily add buttons for their own personal stacks. Custom links directly between any two cards can be added by using a simple procedure native to HyperCard. Although different functions need not be in physically separate stacks, in general our material is organized into *Hewlett-Packard
ScanJetTM.
functionally distinct stacks to facilitate exchange and improvements. The stacks created to date include treatment planning guides, dosimetric calculators, notes, drug information, literature references, department policies, presentation aids, patient files, survival calculators, and miscellaneous others. The exact contents change over time as existing stacks are periodically updated and new stacks are developed. Examples of the workstation stacks are described below. Treatment planning guides These are site-specific guides to treatment planning. Two subjects are nearing completion: brain and gynecologic tumors (Figs l-4). Both contain cards with information on epidemiology, staging, treatment recommendations, and references, as well as clinical data such as isodose distributions and setup instructions. Each stack in the workstation contains a title screen (Fig. 1) with an index of all cards in that stack, as well as buttons for major topics, utilities for stack maintenance, and links to other stacks. Isodose distributions (Fig. 3) are carefully aligned on screen and can rapidly flip back and forth between alternate versions to easily see any differences. Buttons are used to show explanations, branch to set-up information,
Radiation oncology residents’ workstation 0 T. W. ZUSAGer al.
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This is alternate position rbicb can be used for pituitary and ruprarellar tumors, rbetber ares or statio fields are used. The ltmitiag teobnical factor here is the maxtmum rertioal table distanoe belor tsooenter. The ?? ges are ?? asilg kept out of the beam ritb this technique, and most of the brain stem oaa be avoided (albeit vitb beam exit through the pharynx).
Fig. 4. An example of a card showing patient position for a particular type of treatment, Buttons to branch to related topics may be added as desired.
Treatment (100)
time
18.0 x 20.0
13.3
with a short discussion.
calculator Actual dose
Clinac 28
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Fig. 5. Treatment time calculator. Treatment machine designation is made via a pop-up menu when the mouse is clicked over the beam button. Once a choice has been made, default values for distance, technique, etc., are put into the appropriate fields. The two large buttons at top left branch back to the main clinical or physics topic screens.
I
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Calibration da@ s1 COllimaNx settixq Air output incGy/MU hy facwr included n’ng , 1So
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Fig. 6. Machine data screen. Basic hardware parameters are included, as well as four fields for measured data. All data stored in fields consists of strings of characters. A script can interrogate the field to find not only its contents, but also the format of its contents. The number of rows and columns in the dataset are discovered by the script when the calculation is performed, so array dimensions can be altered at will without requiring them to be explicitly stated. Each machine, therefore, need only have as many rows and columns as necessary for the desired calculation
accuracy.
references, and so forth. Inserting new cards, text data, and new navigational links is very easy to do, but designing, entering, and aligning illustrations such as these can be extremely labor intensive. Treatment time calculator This is a sophisticated spreadsheet that does treatment time calculations for megavoltage therapy machines, and is the most complex card in the project (Fig. 5). The user may specify treatment parameters either by clicking within the field of the specific item to be changed, or by entering groups of data values at once. Since stacks contain both data and programs, fields on the card retain values from the previous calculation. Only those items that are different (e.g., field size, depth) need be changed. The user moves the mouse over various areas of the screen and clicks to indicate which of the input data items are to be changed. All entries are checked for contextual validity, and out-of-range values rejected. Intermediate values in the calculation are updated as the individual data items are changed. A suppressable automatic recalculation feature updates the monitor units (or time) as each parameter is changed. Calculation status and instructions are continually displayed within a message field at the center of the screen,
which may also be used to type data in batches. Multiple formats are accepted for certain items, such as field dimensions, where “10 12” or “10 x 12” or “11.1” are all valid entries. Pop-up menus are used to simplify entry of items with a finite number of allowable responses, such as type of beam. When the beam is altered, the standard technique and distance for the new beam are copied automatically into the corresponding data fields, where they may then be adjusted by the user if desired. SAD, SSD, or ARC techniques may be chosen for the calculation. Any parameter that can be set clinically can be specified, so external TAR or SAR results may be entered if desired. Treatment beam data are contained on a separate series of cards within the stack (Fig. 6). Beams can be added, modified, or deleted simply by making the corresponding changes to the data cards. While not particularly complex, the calculations performed nevertheless provide a good indication of Hypercard’s mathematical abilities, the principal limitation of which is speed. About 10 seconds are required on machines with a 68000 processor to perform all the calculations necessary to arrive at a treatment time. The time is most noticable when typing data in batches, since then all of the calculation is done at once instead of being distributed into
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Skingap calculator 26.2
1
Separath between field centers
Save report
1
Nev skingap
11
Help...
H
Explanation
1
7. SkinGap calculator card. The boxed fields are areas which accept user input. A recalculation is done after any item is changed. There are buttons at the bottom to summon help screens, explain rationale, or save a copy of the results on screen for archiving with the patient’s name attached. The use of graphics such as this may help clarify the purpose or methodology of a procedure. Cards may be set up to contain any combination of pictures, text fields, or buttons, depending upon their purpose. Fig.
smaller components if the various parameters are entered individually. Several techniques were tried to optimize calculation speed and accuracy. Initially a curve-fitting technique (2) was used to generate polynomial coefficients for our beam data. By using a subset of the data tables, with adjacent rows and columns chosen about 3% apart, quite good accuracy (- 1% relative to our standard methods) could be obtained using a reduced number of data points, with a noticeable improvement in speed.
Skin gap calculator This is a graphic illustration of one method of calculating skin gaps for abutted fields (Fig. 7). The gap at depth or at skin may be each used as the independent variable, and the other calculated. Screens with explanations of the concepts or help in operation are shown when the user clicks on the buttons at the bottom. A permanent report of an individual calculation can be generated and printed for inclusion into a patient’s chart if desired.
Cancer information A group of several stacks hold disease information, ture notes, literature references, and so on. Graphics
lecmay
be included on any card (Fig. 8), and links can be made to related topics elsewhere in the workstation. Links can be set up as discrete buttons, or embedded within the text fields. Clicking over a word in such a text field results in display of additional information. Isotope decay calculator This card gives the physical constants for some commonly used isotopes, and performs a decay calculation based upon either a time interval or a pair of dates (Fig. 9). Intervals can be specified in any of several units, which the entry routine decodes appropriately. Isotopes can be added or altered simply by making changes in the first two columns. NSD-TDF tutorial This is a stack that explains concepts of NSD and their extension to TDF, and calculates TDF and NSD (Fig. 10). The calculations are based upon the original formulae of Ellis and Orton (5). Values are updated at any data field change. Fractions per week is selected with a pop-up menu. Help fields and TDF tables are available by pressing the Information button. The stacks not illustrated include: Oncodrug, a source of basic information about drugs commonly used in radia-
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distribution X of red uarrow
Anatomical site
in the adult Head . . . . . . . . . . . . . . . . . . . . . . . 13.1 cranium . . . . . . . . . . . . 11.9 1.2 mandible . . . . . . . . . . .
Upper limb girdle 2 humeri . . . . . . . . 2 scapulae. . . . . . . 2 clavicles. . . . . , Sternum
Sacrum Pelvis Femoral
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.
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8.3
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-43
Fig. 8. A pictorial reference card from a stack used to store lecture or course notes. The diagram was digitized on a flatbed scanner from a journal article, while the table was manually typed into a text field. The user may also illustrate notes with simple diagrams drawn with HyperCard’s built-in painting tools.
with a surface-area calculator and conversion tables; Slide and note maker, a specialized presentation manager that can prepare camera-ready copy as well as lecture notes; Patients, a file for the resident to track cases for boards documentation or follow up; and Survival, which does Kaplan-Meier plots on external patient data. tion oncology,
DISCUSSION Among the possible applications for a residents’ workstation, we wanted to develop first components with educational value, but which are also useful in the clinic, in order to increase the likelihood that the workstation will be frequently used. Specific stacks were created to test graphics handling, text storage and retrieval, and calculations, in both use and development. As yet, the workstation is not complete enough, nor have we had enough experience with it, to comment on its relative educational or clinical effectiveness. We believe those observations will follow as its content and structure evolve. We can comment, however, on the suitability of the platform to the application of this workstation. Because we are interested in a system that is practical for the end-user to modify, it is difficult to separate in the discussion that follows the capabilities of the development environment from that of everyday use of finished stacks.
Graphics The use of graphics within these stacks can be very striking and can help clarify a point in a way that words often cannot. For example, fades and dissolves between alternate screens are a particulary effective method for comparison of isodose plots. We are pleased with the ability to present static and dynamic images by a variety of techniques and with simple scripts that can be readily modified. However, design and entry of relevant graphics are labor-intensive and are likely to be a limiting factor in the number of images that can be generated by a single institution. Graphics can be drawn by hand or digitized from existing artwork, but the latter method, while fast, produces images that need extensive manual editing. The Macintosh has the ability to save any screen image and so some of the illustrations, such as isodose plots, could be captured by using it as a graphics terminal connected to a treatment planning computer. As mentioned previously, we decided to limit stack graphics to black-and-white images in a desire to keep the cost of the hardware as low as possible, in order to maximize the number of potential users. As technical advances drive down the cost of color machines, the impact of this decision lessens. HyperCard itself is capable of displaying color and continuous-tone images (3, 4, 8), so radiographs
Radiation
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Isotope
decay
and units leg, 13 hr/days/wks/mo/yr) Half-life
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5.26 60.25 8.04 30 74.25 2.69
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15.5
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Fig. 9. Isotope decay calculator card. The user may type in a decay time in any one of several acceptable formats, or may type calendar dates for the interval. After any change in the time fields, decay factors are computed based upon the values in the half-life column for as many isotopes as are listed. Isotopes may be added or altered simply by typing in the appropriate column.
TDF-NSD 2
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Fig. 10. TDF/NSD tutorial. The calculation routine uses the original exponential formulae and not tables, and is triggered whenever any entry field is changed. Clicking on the information button brings up a discussion of the concepts.
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Text handling HyperCard’s script language has powerful text manipulation functions, which permit fairly sophisticated handlers to be written. This simplifies design of customized handlers for imported data, but does not eliminate the need for some programming skills. With appropriate handlers, importing and reformatting text are quick. From a user’s point of view, text handling is very good. Altering existing text or entering new text is easy. Searches of text (once entered), even large files, are very fast, and can be done over all or just subsets of the text in a given stack. Large amounts of data can be stored with relatively little strain. Hard copies and reports can be generated using built-in functions. Calculations Most typical mathematical functions can be performed within the native scripting language, but operations can be slow on 68000-based machines. Part of this is due to the semicompiled nature of HyperCard’s scripting language, but some is related to the lack of a mathematics coprocessor on the basic Macintosh models. The situation is dramatically better on models with a 68020 or 68030 processor, and calculation speed is excellent. Still, we have not encountered significant limitations for functions important to the workstation even on entry-level machines. Ease of use One of our goals was to make the workstation usable without extensive prior computer training or experience, so that retrieving information would take minimal effort. The features of the platform make this goal very achievable. Reaching it, however, requires considerable attention to design and execution of the stacks. Screens must be simple and organized in a logical fashion. Buttons should be recognizable and consistent in appearance and effect. Any instructions needed should be explicit, and on-screen help should always be available. Finding a topic and searching for related information should take just a few clicks of the mouse. It should be easy to modify and expand the system to include new information or functions. In general, we feel that the system developed meets these expectations. As we gain experience we are identifying areas for improvement through user feedback. Functions and screens which are confusing to persons who have never used a computer before are being simplified wherever possible. Some cards, such as the treatment time cal-
Volume 22, Number
1, 1992
culator, are unavoidably screens may be needed.
complex,
and
additional
help
Expandability Another of our goals was to make modification and expansion of the workstation possible by persons of widely varying abilities. No matter how much effort is expended in initial setup of an information system, it will never be finished. There will always be more data to store, new functions to incorporate, and further associations to be made, a significant fraction of which may be idiosyncratic to the needs of the individual user. Given the framework of an established set of stacks, it is fairly easy to expand and modify the structure. Cards, data, and controls are simple to add and alter, and new stacks can easily be integrated into the existing set without any programming required. Developing complex functions de novo does require familiarity with the scripting language and this is inescapable - but is also true of all other development systems (4). Fortunately the structure and syntax of the language are such that a working knowledge of its fundamentals can be quickly and relatively painlessly acquired. CONCLUSIONS We have begun investigating the feasibility of using the Macintosh and HyperCard as a hardware-software platform for a workstation for radiation oncology residents. We are pleased with the power and capabilities of this platform in both development and use. The hardware is compact and easy to transport and set up. The scripting language is powerful and easy to understand. It is well suited for simple calculations and manipulation of text, black-and-white graphics, and sound, and can be extended with external modules to improve its mathematical abilities or to provide specialized functions. In finished stacks, graphics and text handling are very good, and we are willing to accept some slowness in complex calculations. Sophisticated, well-designed stacks require thoughtful development, but once created they are simple to use. The volume of data that must be included for a reasonably complete system is probably too great to permit a single person or institution to construct the entire workstation. This is not necessary, as modules from third parties can be easily incorporated into the existing set. Furthermore, the end user can customize, extend, and expand an application based on stacks with an ease not found in any other development environment or prepared or special-purpose software that we have seen. This suggests to us that a user-supported residents’ workstation for the radiation oncology community is an attainable goal.
REFERENCES A. L.; Kleffner, J.; Mok, E. C. Computer assisted instruction for radiotherapy residents. Int. J. Radiat. Oncol. Biol. Phys. 10:2345-2349; 1984.
1. Boyer,
2. Horn, R. A. Computer programs for output and depth dose from hyperbolic equations. Med. Phys. 8:108-l 10; 1981. 3. Lynch, P. J. Apple HyperCard: videodisc authoring system
157
Radiation oncology residents’ workstation 0 T. W. Zusac et al. and illustration medium. J. Biocommun. 15:20-5; 1988. McArthur, J. R.; Bolles, J. R.; Fine, J.; Kidd, P.; Bessis, M. Interactive computer-video modules for health sciences education. Methods Inf. Med. 28:36C-3; 1989. Orton, C. G.; Ellis, F. A simplification in the use of the NSD concept in practical radiotherapy. Br. J. Radiol. 46: 529-537; 1973. Peat, Marwick, Main & Co. 1987 systems evaluation approach-computerized audit support effectiveness study. New York: Peat Marwick Main & Co.; 1987. Sherouse, G. W.; Naves, J. L.; Varia, M. A.; Rosenman, J.
A spreadsheet program for brachytherapy planning. Radiat. Oncol. Biol. Phys. 13:639-646; 1987. 8. Spencer, K. A. HyperCard: teaching technology ful learning. J. Audiov. Media Med. 13:25-30;
Int. J.
for success1990.
9. Starkschall, G.; Riggs, J. D. Use of a personal computer and spreadsheet software for treatment machine time calculations. Int. J. Radiat. Oncol. Biol. Phys. 11:1869-1872; 1985. 10. Tan, C. K.; Rajendran, K.; Voon, F. C. Hypertext-based enhancement of medical and dental undergraduate learning. Ann. Acad. Med. Singapore 19:761-7; 1990.
22, pp. 147-157 Copyright
0360.3016/92 $5 00 + .oO 0 1991 Pergamon Press plc
??Technical Innovations and Notes
RADIATION T. W.
ONCOLOGY
ZUSAG,
M.D.,‘*
RESIDENTS’
S. MCDONALD,
J. A. PURDY, PH.D.’
COMPUTER
M.B.,
CH.B.,~
A.
WORKSTATION MILLER, B.A.,2
AND P. RUBIN, M.D.2
‘Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO; and * University of Rochester School of Medicine, Rochester, NY We are investigating the feasibility of using the Macintosh computer as a workstation platform for radiation oncology residents because of its ease of use, graphics capability, and low cost. HyperCard was chosen as the programming environment because it easily mixes graphics, text, and control functions in an integrated screen display. Furthermore, it results in a system that can be relatively easily extended and customized by individual users with varying degrees of computer skills. We have developed several software modules in order to test the ability of this environment to support the demands of such a workstation. Modules created thus far include various clinical physics aids and tutorials, treatment planning guides, oncology databases, and others. The software runs on all Macintosh configurations, but calculation speeds are improved when a 68020 or greater processor is used. In general, we have been pleased with the implementation thus far. Graphics display capability is good, but design and entry of graphics have proved labor-intensive. Searching is fast and text is easily entered and manipulated. Finished modules can be customized with minimal computer training, but implementing complex new functions requires familiarity with HyperCard’s programming language. New modules, once developed, are easily integrated into the workstation universe, suggesting that cooperative development of the workstation by multiple contributors is realistically achievable. Computer workstation,
Computer graphics,
Education,
Resident training, Dosimetry,
HyperCard.
played roles. Text displays present large volumes of information rapidly but command-line interfaces can intimidate novices, particularly those with little extra time for computer training. Illustrations to strengthen the impact and improve comprehension of displayed data often required additional hardware or were implemented with crude, character-based pseudo-graphics (1). The development of icon-based windowing operating systems and hardware optimized for graphics has improved the usefulness and accessibility of computers for the casual user (6). In a field such as radiation oncology, with its technical and 3-dimensional spatial orientation, a graphicsbased personal workstation for clinical and educational applications might prove very useful. Possible contents or functions of such a workstation might include anatomy or CT atlases, treatment planning guides, procedure manuals, dosimetric calculations, tutorials, literature references, personal files, and so on. There have been prior published reports of microcomputer use in radiation oncology, but these have been primitive systems with limited scope, such as spreadsheets for dosimetric cal-
INTRODUCTION
There are many uses to which a computer might be put within the context of a radiation oncology residency program. Information storage, interactive tutorials, on-line library searching, and clerical functions are frequently mentioned. Computers have been used in such roles in the past, typically mainframe or minicomputers running elaborate custom software, but the systems were costly, inflexible, and not widely used. One of the advantages of computerized information sets, namely, the ability to customize the contents and structure according to the needs of the individual user, was rarely realized with these large systems. Powerful and relatively inexpensive microcomputers, which promised a revolution in “personal” computing, have been available for many years but few residents use them much or very efficiently. Several factors may be responsible for the low level of use. Inaccessible user interfaces, complex setup, scarcity of appropriate and useful software, and lack of programming skills have probably all
Presented at the 32nd Annual Meeting of the American Society for Therapeutic Radiology and Oncology, October 1990. *Dr. Zusag is now at the Department of Therapeutic Radiology, Rush Presbyterian St. Luke’s Medical Center, 1753 W. Congress Parkway, Chicago, IL 60612.
Reprint requests to: James A. Purdy, Washington School of Medicine, 510 So. Kingshighway Blvd., MO 63110. Accepted for publication 24 May 1991. 147
University St. Louis,
148
I. J. Radiation Oncology 0 Biology 0 Physics
Cervix
Volume 22, Number 1, 1992
inFo
Cancer of the Cervix
$!logg? ?
Hist
Help
Tom Zusag, MD
MII? trecpolicies
edXck
hen 8~ see index-
I
Isodoses
Pty @cks
Personal stacks
Fig. 1. The index card of a treatment planning guide. All of the stacks have index cards with a similar format. Five buttons in the middle allow branching to basic categories of information within the stack. Clicking on the title field hides it to reveal the index of all cards in the stack. The buttons in the right column are for utilities such as searching
or stack repair, or for branching to other workstation areas or to outside stacks, such as the HyperCard “Home” stack.
culations (7, 9), or drill programs for physics training (1). No integrated multipurpose software has been described, either mainframe or desktop-based.
METHODS
AND MATERIALS
Hardware Our goal is to develop a functional, compact, low-cost workstation. The ideal system should be universally available, powerful, easy to use, and expandable and configurable by the end user. Although intended primarily for radiation therapy residents, it has become apparent that such a system could be a desirable addition to the clinic. With residents as the target audience, however, cost becomes an important issue. At present, this precludes requiring the use of specialized hardware such as color displays or videodisk storage devices (4). Nevertheless, one would want to preserve expansion options for those with larger budgets, or for technical advances in the future. Several microcomputers from various manufacturers have become available in recent years that employ, or can be used with, graphics interfaces. We chose the Macintosh* as the basic hardware device. It is a personal computer based upon the Motorola 68000 processor series. It *Macintosh
is a trademark of Apple Computer.
features an icon-based operating system, and is simple to configure and use, relatively inexpensive, and widely available. Graphics display, mouse, printer and hard disk interfaces, and digitized audio capability are standard on all models. The small monochrome screen used on the basic models cannot display color or continuous-tone images but is capable of black-and-white bitmapped graphics of a quality sufficient for many applications. The various software packages all have a similar look and feel and share a common set of core commands for basic operations. This makes unfamiliar programs less intimidating and facilitates their introduction without extensive retraining. Software that runs on basic machines is upward compatible without modification on more advanced models, so future expansion and more elaborate systems are possible for those with larger budgets. The system described in this article will run on any Macintosh with 1 megabyte or more of memory and at least 2-800k floppy drives or a hard disk drive. Programming environment We wanted the system to be modifiable by end users whose computer experience may vary widely. We intend to distribute it freely, and ultimately we would like to see
Radiation oncology residents’ workstation ??T. W. ZUSAGet al.
Cervix
149
ports
To
cover pamnrtk nodes
Added for common iliac nodes standard portal Added for vaginal exmsion
Mlf? treatment
Staging diagram
policies
Ceruix references
Nodal drainage
Return
Fig. 2. A typical field diagram from a treatment planning guide. Multiple such cards may be included within a given stack. Buttons at the top left branch back to other clinical stacks or to the title card, while those at the bottom link to related topics.
this project evolve as a group effort within the radiation oncology community. With this in mind, we chose HyperCard? as the programming environment. HyperCard is part of the standard system software of the Macintosh. Although it has resisted brief definitions, it can be considered a graphics-and-text information storage and authoring system (3, 4, 8, 10). It operates on a “stack of cards” metaphor. Each screen display (“card”) in the file (“stack”) contains text fields, graphics and various controls (“buttons”). Buttons are areas on screen containing a word and/or a small graphic called an icon intended to indicate their function. They are activated by a click of the mouse, and can be configured to perform calculations, manipulate data, or navigate to any other card in the same or another stack. Stacks contain data as well as the programming that manipulates the data, and the structure is extensible: data, functions, and controls can be added or altered at will. HyperCard features a high-level English-like programming language with a full array of string, boolean, and mathematical operators. It also has built-in clock and calendar functions, and routines to handle input/output, sound, and graphics. Programs are called scripts and consist of one or more subroutines or handlers. Scripts have tHypercard is a trademark of Apple Computer.
the ability to call external subprograms written in compiled languages such as Pascal and C for specialized needs. Fairly complex scripts are possible; nevertheless, simple functions such as linking two screens for serial display may be implemented without any programming skills. Multiple scripts may be embedded into the stacks upon which they operate. A script may be associated with any button, field, or card in the stack, and its routines will be activated when a specific triggering event is detected. Examples of events are clicks of the mouse button, changes to text fields, and so forth. All of the programming consists of scripts and external subprograms. The scripts in the project are more than 99% our own work; however, scripts or techniques from public domain sources were adapted if they could improve certain functions. Included in this fashion are several external subroutines used for statistical functions, file manipulation, and so on. Some of these came from Apple and some from other educational sources. No commercial material or material that requires licensing was used. Data Raw data for the project stacks were abstracted from various private and published sources, such as lecture
I. .I. Radiation
Oncology
0 Biology 0 Physics
Composioedistribution
Volume 22, Number
Inilial fields: 5000 cGy vhole brain
1, 1992
Boost fields: 1500 cGy weighed 2:l
Show info Compare to unilateral
tumor
11 Position -_ __
.._._.
.I_
.
Fig. 3. A sample isodose card from a treatment planning guide. The user can compare this to other treatment schemes and tumor configurations by clicking on the buttons shown. Alternate distributions on other cards are aligned so that differences are easily seen as one image dissolves into another. Other buttons give detailed discussion of the pros and cons of a given technique, or permit navigation to cards which give setup position and anatomical field orientation.
notes, presentations, departmental treatment policy manuals, and clinical data books. Illustrations were hand-drawn on screen using HyperCard’s built-in tools, digitized from existing artwork using a flatbed scannet+, or imported from public domain files. Scanned material often required extensive retouching to clean up artifacts produced in the process of digitizing continuous-tone images or line drawings. IMPLEMENTATION About a dozen stacks have been created to date, containing in aggregate over 2.50 cards. They can be grouped into three functional categories: dosimetry and physics, clinical information, and personal productivity aids. Each of these categories is represented in a central “Home” stack by one or more screens (not shown) containing buttons for navigating out to the various stacks or cards associated with that category. Users can navigate anywhere in the workstation universe with a maximum of three mouse clicks, and can easily add buttons for their own personal stacks. Custom links directly between any two cards can be added by using a simple procedure native to HyperCard. Although different functions need not be in physically separate stacks, in general our material is organized into *Hewlett-Packard
ScanJetTM.
functionally distinct stacks to facilitate exchange and improvements. The stacks created to date include treatment planning guides, dosimetric calculators, notes, drug information, literature references, department policies, presentation aids, patient files, survival calculators, and miscellaneous others. The exact contents change over time as existing stacks are periodically updated and new stacks are developed. Examples of the workstation stacks are described below. Treatment planning guides These are site-specific guides to treatment planning. Two subjects are nearing completion: brain and gynecologic tumors (Figs l-4). Both contain cards with information on epidemiology, staging, treatment recommendations, and references, as well as clinical data such as isodose distributions and setup instructions. Each stack in the workstation contains a title screen (Fig. 1) with an index of all cards in that stack, as well as buttons for major topics, utilities for stack maintenance, and links to other stacks. Isodose distributions (Fig. 3) are carefully aligned on screen and can rapidly flip back and forth between alternate versions to easily see any differences. Buttons are used to show explanations, branch to set-up information,
Radiation oncology residents’ workstation 0 T. W. ZUSAGer al.
151
This is alternate position rbicb can be used for pituitary and ruprarellar tumors, rbetber ares or statio fields are used. The ltmitiag teobnical factor here is the maxtmum rertioal table distanoe belor tsooenter. The ?? ges are ?? asilg kept out of the beam ritb this technique, and most of the brain stem oaa be avoided (albeit vitb beam exit through the pharynx).
Fig. 4. An example of a card showing patient position for a particular type of treatment, Buttons to branch to related topics may be added as desired.
Treatment (100)
time
18.0 x 20.0
13.3
with a short discussion.
calculator Actual dose
Clinac 28
0.966 Output rrd/MU for 10.0 c 1.017 Collimatqr factor 10.0 1 .g30 Inrsqr
1
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8.674 1.241
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13.3 cm jaws at 101.5 cm
28e
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0.847 Net cGg/MU
avid Entry
cm
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I
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Fig. 5. Treatment time calculator. Treatment machine designation is made via a pop-up menu when the mouse is clicked over the beam button. Once a choice has been made, default values for distance, technique, etc., are put into the appropriate fields. The two large buttons at top left branch back to the main clinical or physics topic screens.
I
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Calibration da@ s1 COllimaNx settixq Air output incGy/MU hy facwr included n’ng , 1So
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Fig. 6. Machine data screen. Basic hardware parameters are included, as well as four fields for measured data. All data stored in fields consists of strings of characters. A script can interrogate the field to find not only its contents, but also the format of its contents. The number of rows and columns in the dataset are discovered by the script when the calculation is performed, so array dimensions can be altered at will without requiring them to be explicitly stated. Each machine, therefore, need only have as many rows and columns as necessary for the desired calculation
accuracy.
references, and so forth. Inserting new cards, text data, and new navigational links is very easy to do, but designing, entering, and aligning illustrations such as these can be extremely labor intensive. Treatment time calculator This is a sophisticated spreadsheet that does treatment time calculations for megavoltage therapy machines, and is the most complex card in the project (Fig. 5). The user may specify treatment parameters either by clicking within the field of the specific item to be changed, or by entering groups of data values at once. Since stacks contain both data and programs, fields on the card retain values from the previous calculation. Only those items that are different (e.g., field size, depth) need be changed. The user moves the mouse over various areas of the screen and clicks to indicate which of the input data items are to be changed. All entries are checked for contextual validity, and out-of-range values rejected. Intermediate values in the calculation are updated as the individual data items are changed. A suppressable automatic recalculation feature updates the monitor units (or time) as each parameter is changed. Calculation status and instructions are continually displayed within a message field at the center of the screen,
which may also be used to type data in batches. Multiple formats are accepted for certain items, such as field dimensions, where “10 12” or “10 x 12” or “11.1” are all valid entries. Pop-up menus are used to simplify entry of items with a finite number of allowable responses, such as type of beam. When the beam is altered, the standard technique and distance for the new beam are copied automatically into the corresponding data fields, where they may then be adjusted by the user if desired. SAD, SSD, or ARC techniques may be chosen for the calculation. Any parameter that can be set clinically can be specified, so external TAR or SAR results may be entered if desired. Treatment beam data are contained on a separate series of cards within the stack (Fig. 6). Beams can be added, modified, or deleted simply by making the corresponding changes to the data cards. While not particularly complex, the calculations performed nevertheless provide a good indication of Hypercard’s mathematical abilities, the principal limitation of which is speed. About 10 seconds are required on machines with a 68000 processor to perform all the calculations necessary to arrive at a treatment time. The time is most noticable when typing data in batches, since then all of the calculation is done at once instead of being distributed into
Radiation
oncology
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Skingap calculator 26.2
1
Separath between field centers
Save report
1
Nev skingap
11
Help...
H
Explanation
1
7. SkinGap calculator card. The boxed fields are areas which accept user input. A recalculation is done after any item is changed. There are buttons at the bottom to summon help screens, explain rationale, or save a copy of the results on screen for archiving with the patient’s name attached. The use of graphics such as this may help clarify the purpose or methodology of a procedure. Cards may be set up to contain any combination of pictures, text fields, or buttons, depending upon their purpose. Fig.
smaller components if the various parameters are entered individually. Several techniques were tried to optimize calculation speed and accuracy. Initially a curve-fitting technique (2) was used to generate polynomial coefficients for our beam data. By using a subset of the data tables, with adjacent rows and columns chosen about 3% apart, quite good accuracy (- 1% relative to our standard methods) could be obtained using a reduced number of data points, with a noticeable improvement in speed.
Skin gap calculator This is a graphic illustration of one method of calculating skin gaps for abutted fields (Fig. 7). The gap at depth or at skin may be each used as the independent variable, and the other calculated. Screens with explanations of the concepts or help in operation are shown when the user clicks on the buttons at the bottom. A permanent report of an individual calculation can be generated and printed for inclusion into a patient’s chart if desired.
Cancer information A group of several stacks hold disease information, ture notes, literature references, and so on. Graphics
lecmay
be included on any card (Fig. 8), and links can be made to related topics elsewhere in the workstation. Links can be set up as discrete buttons, or embedded within the text fields. Clicking over a word in such a text field results in display of additional information. Isotope decay calculator This card gives the physical constants for some commonly used isotopes, and performs a decay calculation based upon either a time interval or a pair of dates (Fig. 9). Intervals can be specified in any of several units, which the entry routine decodes appropriately. Isotopes can be added or altered simply by making changes in the first two columns. NSD-TDF tutorial This is a stack that explains concepts of NSD and their extension to TDF, and calculates TDF and NSD (Fig. 10). The calculations are based upon the original formulae of Ellis and Orton (5). Values are updated at any data field change. Fractions per week is selected with a pop-up menu. Help fields and TDF tables are available by pressing the Information button. The stacks not illustrated include: Oncodrug, a source of basic information about drugs commonly used in radia-
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distribution X of red uarrow
Anatomical site
in the adult Head . . . . . . . . . . . . . . . . . . . . . . . 13.1 cranium . . . . . . . . . . . . 11.9 1.2 mandible . . . . . . . . . . .
Upper limb girdle 2 humeri . . . . . . . . 2 scapulae. . . . . . . 2 clavicles. . . . . , Sternum
Sacrum Pelvis Femoral
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-43
Fig. 8. A pictorial reference card from a stack used to store lecture or course notes. The diagram was digitized on a flatbed scanner from a journal article, while the table was manually typed into a text field. The user may also illustrate notes with simple diagrams drawn with HyperCard’s built-in painting tools.
with a surface-area calculator and conversion tables; Slide and note maker, a specialized presentation manager that can prepare camera-ready copy as well as lecture notes; Patients, a file for the resident to track cases for boards documentation or follow up; and Survival, which does Kaplan-Meier plots on external patient data. tion oncology,
DISCUSSION Among the possible applications for a residents’ workstation, we wanted to develop first components with educational value, but which are also useful in the clinic, in order to increase the likelihood that the workstation will be frequently used. Specific stacks were created to test graphics handling, text storage and retrieval, and calculations, in both use and development. As yet, the workstation is not complete enough, nor have we had enough experience with it, to comment on its relative educational or clinical effectiveness. We believe those observations will follow as its content and structure evolve. We can comment, however, on the suitability of the platform to the application of this workstation. Because we are interested in a system that is practical for the end-user to modify, it is difficult to separate in the discussion that follows the capabilities of the development environment from that of everyday use of finished stacks.
Graphics The use of graphics within these stacks can be very striking and can help clarify a point in a way that words often cannot. For example, fades and dissolves between alternate screens are a particulary effective method for comparison of isodose plots. We are pleased with the ability to present static and dynamic images by a variety of techniques and with simple scripts that can be readily modified. However, design and entry of relevant graphics are labor-intensive and are likely to be a limiting factor in the number of images that can be generated by a single institution. Graphics can be drawn by hand or digitized from existing artwork, but the latter method, while fast, produces images that need extensive manual editing. The Macintosh has the ability to save any screen image and so some of the illustrations, such as isodose plots, could be captured by using it as a graphics terminal connected to a treatment planning computer. As mentioned previously, we decided to limit stack graphics to black-and-white images in a desire to keep the cost of the hardware as low as possible, in order to maximize the number of potential users. As technical advances drive down the cost of color machines, the impact of this decision lessens. HyperCard itself is capable of displaying color and continuous-tone images (3, 4, 8), so radiographs
Radiation
oncology
residents’ workstation
Isotope
decay
and units leg, 13 hr/days/wks/mo/yr) Half-life
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Edit start or end dates (mo/da/yr) here --> orentertime
15.5
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Fig. 9. Isotope decay calculator card. The user may type in a decay time in any one of several acceptable formats, or may type calendar dates for the interval. After any change in the time fields, decay factors are computed based upon the values in the half-life column for as many isotopes as are listed. Isotopes may be added or altered simply by typing in the appropriate column.
TDF-NSD 2
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Fig. 10. TDF/NSD tutorial. The calculation routine uses the original exponential formulae and not tables, and is triggered whenever any entry field is changed. Clicking on the information button brings up a discussion of the concepts.
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Oncology
given the necessary
0 Biology 0 Physics
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and a
Text handling HyperCard’s script language has powerful text manipulation functions, which permit fairly sophisticated handlers to be written. This simplifies design of customized handlers for imported data, but does not eliminate the need for some programming skills. With appropriate handlers, importing and reformatting text are quick. From a user’s point of view, text handling is very good. Altering existing text or entering new text is easy. Searches of text (once entered), even large files, are very fast, and can be done over all or just subsets of the text in a given stack. Large amounts of data can be stored with relatively little strain. Hard copies and reports can be generated using built-in functions. Calculations Most typical mathematical functions can be performed within the native scripting language, but operations can be slow on 68000-based machines. Part of this is due to the semicompiled nature of HyperCard’s scripting language, but some is related to the lack of a mathematics coprocessor on the basic Macintosh models. The situation is dramatically better on models with a 68020 or 68030 processor, and calculation speed is excellent. Still, we have not encountered significant limitations for functions important to the workstation even on entry-level machines. Ease of use One of our goals was to make the workstation usable without extensive prior computer training or experience, so that retrieving information would take minimal effort. The features of the platform make this goal very achievable. Reaching it, however, requires considerable attention to design and execution of the stacks. Screens must be simple and organized in a logical fashion. Buttons should be recognizable and consistent in appearance and effect. Any instructions needed should be explicit, and on-screen help should always be available. Finding a topic and searching for related information should take just a few clicks of the mouse. It should be easy to modify and expand the system to include new information or functions. In general, we feel that the system developed meets these expectations. As we gain experience we are identifying areas for improvement through user feedback. Functions and screens which are confusing to persons who have never used a computer before are being simplified wherever possible. Some cards, such as the treatment time cal-
Volume 22, Number
1, 1992
culator, are unavoidably screens may be needed.
complex,
and
additional
help
Expandability Another of our goals was to make modification and expansion of the workstation possible by persons of widely varying abilities. No matter how much effort is expended in initial setup of an information system, it will never be finished. There will always be more data to store, new functions to incorporate, and further associations to be made, a significant fraction of which may be idiosyncratic to the needs of the individual user. Given the framework of an established set of stacks, it is fairly easy to expand and modify the structure. Cards, data, and controls are simple to add and alter, and new stacks can easily be integrated into the existing set without any programming required. Developing complex functions de novo does require familiarity with the scripting language and this is inescapable - but is also true of all other development systems (4). Fortunately the structure and syntax of the language are such that a working knowledge of its fundamentals can be quickly and relatively painlessly acquired. CONCLUSIONS We have begun investigating the feasibility of using the Macintosh and HyperCard as a hardware-software platform for a workstation for radiation oncology residents. We are pleased with the power and capabilities of this platform in both development and use. The hardware is compact and easy to transport and set up. The scripting language is powerful and easy to understand. It is well suited for simple calculations and manipulation of text, black-and-white graphics, and sound, and can be extended with external modules to improve its mathematical abilities or to provide specialized functions. In finished stacks, graphics and text handling are very good, and we are willing to accept some slowness in complex calculations. Sophisticated, well-designed stacks require thoughtful development, but once created they are simple to use. The volume of data that must be included for a reasonably complete system is probably too great to permit a single person or institution to construct the entire workstation. This is not necessary, as modules from third parties can be easily incorporated into the existing set. Furthermore, the end user can customize, extend, and expand an application based on stacks with an ease not found in any other development environment or prepared or special-purpose software that we have seen. This suggests to us that a user-supported residents’ workstation for the radiation oncology community is an attainable goal.
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