Go Back

Transition from 2D to 3D CRT and IMRT


Basic treatment capabilities with minimal imaging support have been labelled as 2D RT (2D radiotherapy). With more advanced imaging and dose calculation capabilities for treatment planning, and more sophisticated treatment delivery procedures, 3D conformal radiotherapy (3D CRT) can be provided. Further sophistication in treatment planning and treatment delivery capabilities allow for intensity-modulated radiotherapy (IMRT). There are significant differences between conventional 2D RT treatment planning and delivery and 3D CRT. To establish 3D CRT in an institution a number of steps should be taken. This includes the definition of the scope of the programme, developing staffing needs, training of all personnel to be involved, acceptance testing and commissioning of the new equipment and the development and implementation of a comprehensive QA programme. IMRT techniques are significantly more complex than 3D CRT and require the close collaboration and expertise of an appropriately-trained multidisciplinary team, including radiation oncologists, medical physicists, and radiation technologists.

Important Principles

A complete understanding of all steps is necessary before one can successfully begin a new programme in 3D CRT. It is important to allow sufficient time for physics staff training prior to the arrival of the equipment so that trained staff are in place to carry out acceptance testing and commissioning. Only radiation oncology departments that have sufficient experience with 3D CRT are in a position to transition to IMRT. Adequate training in IMRT technology for all members of the team is essential prior to the initiation of such a programme. Ideally, the team members are best trained on equipment that they plan to use for IMRT in their own department.

Introduction to References

IAEA-TECDOC-1588 is divided into two parts: 3D CRT and IMRT. It provides guidelines, and highlights the milestones that are to be achieved for the transition from 2D RT through 3D CRT to IMRT. The report is written as an extension to IAEA-TECDOC-1296 and should be consulted in conjunction with that report. The two journal articles describe in detail the transition from 3D CRT to IMRT. IAEA web page "Transitioning from 2-D Radiation Therapy to 3-D Conformal Radiation Therapy and Intensity Modulated Radiation Therapy" contains training material that has been developed for this purpose.