To the Editor:
The third edition of the American Society of Hematology (ASH) Slide Bank contains well over 5,000 hematopathologic images of great use to hematology educators and trainees. The University of Washington Health Sciences Center for Educational Resources (http://cer.hs.washington.edu/hscer) serves as the Slide Bank archivist and agent. From them, images and image sets can be purchased in various forms. The images originally were available only as 35-mm slides, but subsequently were made available on laser videodisc1 and CD-ROM media. When used in a program serving many trainees, these products have several drawbacks, including: (1) the requirement for the user to physically possess the media to see the images, and (2) the risk of loss of, or damage to, the media through repeated handling by various users. (Loss is the most common.) As director of my institution’s hematology training program, I was interested in improving faculty and trainee access to the Slide Bank while reducing the risk for media damage or loss. Other collections of medical images have been made available through the web successfully for several years now.2-4 I sought to construct a web interface to the Slide Bank CD-ROM.
With materials and funding support from Microsoft and Ortho Biotech, respectively, in January 1998 I purchased for my training program the Slide Bank’s Heme CD. This is the second digital edition. It contains a selection of approximately 2,400 Slide Bank images covering the gamut of normal and abnormal hematology. Analysis of this CD-ROM showed that the images were in standard Joint Photographic Expert Group (JPEG) format and that the image index was a database in a format (Microsoft FoxPro) readily accessible via industry-standard Open DataBase Connectivity (ODBC) software. Most web browsers can display JPEG images, and there are many ways to interface web servers to ODBC (and, thus, to the databases accessible through ODBC).
I permanently installed the CD-ROM into the computer hosting my training program’s World Wide Web site (operating system: Microsoft [Redmond, WA] Windows NT Server 4.0; web server: O’Reilly & Associates, Inc’s [Sebastopol, CA] WebSite Pro). I used Allaire, Inc’s (Cambridge, MA) Cold Fusion package to program an interface between WebSite Pro and the web server computer’s ODBC module. Thus, the CD-ROM effectively became accessible via any web browser (see Fig 1). Web server security was configured to limit access in compliance with the CD-ROM’s license. When displaying a Slide Bank image in the user’s browser, the interface cautions the user to give appropriate credit to the ASH Slide Bank and the original contributor of the image (as per the license).
Accessing the ASH Slide Bank CD-ROM from the web: a user running a web browser on an authorized workstation connected to the Internet makes a request for a page from the Slide Bank web interface (generally by clicking on a link to the interface’s home page). The requested page is actually a Cold Fusion “template” containing a mix of web-standard HyperText Markup Language codes (“tags”) interlaced with Cold Fusion tags directing the Cold Fusion “middleware” engine to perform various database operations. The web server receives the request, sees that the requested page is a CF template, and passes the request to the CF engine. CF strips the CF tags out of the template, performing database operations and substituting results in place of the tags as appropriate. After it finishes processing the template thusly, the page (HTML-only at this point) is passed back to the web server for return to the browser. Web server security is configured so that only workstations (on-campus or not) connected directly into the campus network are permitted access to the Slide Bank interface.
Accessing the ASH Slide Bank CD-ROM from the web: a user running a web browser on an authorized workstation connected to the Internet makes a request for a page from the Slide Bank web interface (generally by clicking on a link to the interface’s home page). The requested page is actually a Cold Fusion “template” containing a mix of web-standard HyperText Markup Language codes (“tags”) interlaced with Cold Fusion tags directing the Cold Fusion “middleware” engine to perform various database operations. The web server receives the request, sees that the requested page is a CF template, and passes the request to the CF engine. CF strips the CF tags out of the template, performing database operations and substituting results in place of the tags as appropriate. After it finishes processing the template thusly, the page (HTML-only at this point) is passed back to the web server for return to the browser. Web server security is configured so that only workstations (on-campus or not) connected directly into the campus network are permitted access to the Slide Bank interface.
The user surfs to the project’s home page, from which can be selected the hematologic topic of interest. Small versions (“thumbnails”) of relevant images are shown first (along with any related information, such as descriptions of the images, listed in the images’ entries in the index database); each thumbnail is linked to a larger version. Most browsers provide means for copying displayed JPEG images into other programs. Thus, it is trivial for the user to incorporate Slide Bank images into computer-based presentations that can be created with software packages such as Microsoft PowerPoint.
Recent review of web server access logs show that many hundreds of images have been accessed since the interface was made available to our faculty and trainees. Images are accessed 7 days a week at all hours of the day and night, from on- and off-campus locations. Faculty and trainees have incorporated Slide Bank images into presentations for teaching purposes. No security breaches or license violations have been identified.
This web interface to the Heme CD appears to satisfy the goals of improving access to Slide Bank images while reducing (in fact, eliminating) the risk for media damage or loss from normal use. Other hematology training programs may wish to replicate this project using their own licensed copies of the Heme CD. The interface (Cold Fusion code) is available without charge; requests can be e-mailed toafrinl@musc.edu.
