Patient setup for PET/CT acquisition in radiotherapy planning

PET/CT imaging modalities have been shown to be useful in the diagnosis, staging, and monitoring of malignant diseases. Its inclusion into the treatment planning process is now central to modern radiotherapy practice. However, it is essential to be cognisant of the factors that are necessary in order to ensure that the acquired images are consistent with the requirements for both treatment planning and treatment delivery. Essential parameters required in image acquisition for radiotherapy planning and treatment include consistencies of table tops and the use of laser light for patient set-up. But they also include the accurate definition of the patient's initial positioning and the use of proper immobilization devices in the radiotherapy department. While determining this optimum set-up, patient psychological factors and limitations that may be due to the subsequent use of PET/CT for planning purposes need to be taken into account. Furthermore, patient set-up data need to be properly recorded and transmitted to the imaging departments. To ensure the consistency of patient set-up, the radiation therapist should ideally be directly involved in informing and positioning the patient on the PET/CT. However, a proper exchange of patient-related information can also be achieved by a close liaison between the two departments and by the use of clear detailed protocols per type of patient set-up and/or per localization of tumour site.