G T Doswell | PubMed Health

PubMed1995

Software control procedures for treatment planning systems.

In radiotherapy treatment planning systems, the software programs as well as the beam data have to be updated frequently, when new software versions are released or as beam data change. This update procedure has to be carried out carefully, to ensure the integrity of the system software and data. Moreover, the version of software used for a particular patient treatment plan is important, not only as a record to be retrieved when necessary, but also when there are multiple terminals connected to the same computer. This process of version control is not always carried out in a systematic and standardized fashion. Most clinics often have their own systems to implement this procedure, but while some systems are comprehensive, others may not necessarily incorporate enough safeguards for errors. In addition, treatment planning system manufacturers often do not offer well-designed and fail-safe facilities for this important issue. This report describes the software update control procedures we have implemented on our treatment planning system as well as suggests some general principles that could be applied to other planning systems.

Computer Systems↗

PubMed1992

Treatment planning for the breast patient: with or without lung correction?

Patients who have undergone a surgical lumpectomy for breast cancer are routinely referred to our clinic for a course of radiation therapy. This treatment consists of a pair of obliquely opposing radiation fields that encompass the breast and underlying structures. In order to treat the chest wall, a portion of lung must be included in this target volume, as breast tumours can invade the underlying chest wall due to direct invasion, blood invasion, or lymphatic permeation. At our clinic, we have always included this volume as normal tissue (with normal tissue density); thus, an inhomogeneity correction has never been generated on any breast plan. The aim of our study was to accurately measure the volume of lung within the treatment fields at time of simulation, using the simulator films and patient parameters, and to determine the point at which this volume of lung significantly altered the computer plan. This would necessitate the generation of a new distribution in order to produce a homogeneous dose to within +/- 5%. A table was constructed to identify those patients who had excessive lung volumes. At time of simulation it would be possible, using the table, to determine the type of treatment plan required for each patient. Those patients demonstrating an excessive lung volume would require a more extensive planning procedure utilizing CT (computerized tomography). An inhomogeneity correction could then be applied to the computerized distribution.

Breast Neoplasms↗