Treatment Planning System

2. Treatment Planning System

The tutorial is written with reference to the Prism treatment planning software 1,2 , which has been developed at the University of Washington,

1 Kalet I.J., Jacky J.P., Austin-Seymour M.M., Hummel S.M., Sullivan K.J. and Unger J.M., Prism: a new approach to radiotherapy planning software , Int J Radiat Oncol Biol Phys 36:451-461, 1996.

Seattle, WA, USA. The Prism TPS offers several features, which are valuable for educational use. Prism is straightforward to use, possesses all main features of a modern TPS (i.e. full three dimensional capabilities) and is DICOM (Digital Imaging and Communications in Medicine standard) compatible. While the source-code and documentation of Prism are freely available for non-profit educational

use, currently in order to run Prism an Allegro Common LISP 3 license has to be purchased. A one-off licence is available at relatively small

cost and this is the only expense beside a PC. Note that we are investigating the use of Prism without requiring users to have fully- paid licenses for Allegro CL by creating an Allegro runtime

application 4 . Prism runs on a Linux environment and the hardware requirements are low and lie well within the specifications of current

standard PCs. The installation of Prism is well-documented 5 and straightforward.

Prism can be run and displayed locally on the Linux computer where it is installed, but it is also possible to redirect the display to another computer using an X terminal. This allows multiple users from remote PCs to simultaneously connect to Prism at the same time but each user can run an independent Prism session, which is redirected and displayed locally on the user’s PC. At the University of Canterbury sessions with about 10 remote connections to the main PC have been conducted without any noticeable impact on the performance of individual sessions.

Another valuable Prism feature with regards to multiple tutorial users is that it contains a main database, accessible by all users, as well as a customizable local database for each individual user, as illustrated in

2 University of Washington, The Prism Radiation Treatment Planning Project, [cited November 23, 2009], available from

http://www.radonc.washington.edu/medinfo/prism/ , 2009.

3 Allegro Common Lisp 8.q, [cited March 6, 2009], available from http://www.franz.com/products/allegrocl/ , 2009.

4 Allegro CL version 8.1, Allegro CL Runtime, [cited November 25, 2009], available from http://www.franz.com/support/documentation/8.1/doc/runtime.htm#runtime-intro-1

5 Kalet I.J., SLIK Programmer’s Guide, Version 2.1 (Technical Report), Radiation Oncology Department, University of Washington, Seattle, WA, USA, 2004.

Figure 1. This allows for easy maintenance and avoids that the main database becomes cluttered.

Prism comes with a fully functioning DICOM server, which makes the system compatible with other TPSs. Figure 1 also illustrates the Prism DICOM environment. The Prism DICOM server can receive DICOM CT images and DICOM RS structure sets and can export DICOM RTP treatment plans as are typically sent to a record and verify system or directly to a linear accelerator. Note that for the tutorial the same external DICOM server was used to send DICOM CT images and radiotherapy structure sets (RS) to Prism and to receive completed Radiotherapy Plans (RTP) from Prism, simulating the therapy machine.

Figure 1: The Prism environment

The modular design of Prism, consisting of different panels, allows adding or changing data items in the treatment plan at any time rather than enforcing a sequence of operations. This makes the system flexible and avoids that students learn a particular sequence, as required for some commercial treatment planning system, but encourages them to consider (and therefore understand) each step in The modular design of Prism, consisting of different panels, allows adding or changing data items in the treatment plan at any time rather than enforcing a sequence of operations. This makes the system flexible and avoids that students learn a particular sequence, as required for some commercial treatment planning system, but encourages them to consider (and therefore understand) each step in

Due to the modular design and the use of Lisp as programming language Prism is highly customizable and functionality can easily be added or changed. Several other programs, all of which are open- source helped to embed Prism in a well-operating environment. More

details can be found elsewhere 6 .