Abstract book - ESTRO meets Asia

S14 ESTRO meets Asia 2018

± 1.21% with and without 5.0 mm MLC, and there was no significant difference between two groups (p > 0.05).

determining the most suitable treatment plan, and can help us to reduce errors. In addition, it has attracted interest in the fields of molecular and functional imaging for primary-to-metastatic cancer screening and functional neuroimaging. Therefore, the application of multi- modality imaging should lead to a better and more reliable diagnosis and treatment. Intrafraction motion has been an issue that is becoming increasingly important in the era of IGRT. Estimation of surrogated respiration motion through breathing cycle and 4D images is the biggest focus to correlate with actual organ motion. If target is moving, we need to use larger beam field, which delivers extra radiation dose to normal tissue. The solutions to avoid this extra dose to normal tissue by moving organ are to utilize respiratory motion control techniques. Therefore, we are studying common methods used in the management of respiration motion in radiation therapy: breath-hold, gating, and tumor tracking techniques. These techniques are generally implemented through four steps: (1) localization consisted of respiratory signal control and image guidance, (2) planning (3) verification, and (4) delivery. The analysis of the multi-modality images and image registration provide useful information in delineating the target volume for radiation treatment planning (RTP). In addition, we need more accurate time-resolved 4D localization technique for modeling the intrafraction organ motion. SP-034 The role of functional imaging in guiding radiation therapy M. Aznar 1 SP-035 Optimising image verification procedures at the treatment console A. Leong 1 1 Bowen Icon Cancer Centre, Wellington, New Zealand Abstract text Image-guidance has become standard practice for the vast majority of radiation therapy indications. However, there are a wide variety of imaging modalities available at the treatment console which can themselves be utilised in a range of different ways. An ‘optimal’ image-guidance protocol for any single treatment site can be difficult to define when considering the often-limited clinical evidence available as well as the diversity of radiation oncology resourcing internationally.This lecture will explore the imaging technologies available to guide radiation therapy treatment as well as factors that should be considered in their day-to-day clinical application. The importance of tailoring image-guidance procedures to the local clinical context will be discussed with consideration of the available departmental resources. 1 The Finsen Center - RigshospitaletSection for Radiotherapy Department of Oncology 3993, Copenhagen, Denmark Abstract not received

Conclusion In brain SRS plan with a SIDCA technique, the distance of IC to PTV and usage of 5.0 mm MLCs for planning did not affect the dosimetric errors.

Teaching lecture: Dose response, therapeutic ratio

SP-032 Dose response, therapeutic ratio M. Joiner 1 1 Karmanos Cancer Institute Wayne State University, Detroit, USA

Abstract not received

Teaching lecture: IGRT and treatment verification

SP-033 Image Guided Application in Radiation Therapy T.S. Suh 1 1 The Catholic University of Korea, College of Medicine- Biomedical Engineering, Seoul, Korea Republic of Abstract text Recently, advances in medical imaging technology have accelerated the development of medical physics: the utilization of images in diagnosis and radiation therapy such as intensity modulated radiation therapy (IMRT), image guided radiation therapy (IGRT), Tomotherapy and Robot-guided RT. Single or multi-modality imaging for static or dynamic target has been applied in the field of medical physics to determine the local tumor volume and location of the tumor. While all radiation therapy are more or less image guided traditionally, imaging technology has primarily been used in producing 3D information of patient anatomy to identify the location of the tumor to treatment. New radiation treatment technique derived from the image guided technique has been developed to optimize the accuracy of radiotherapy. Especially, image guided applications are classified into two major aspects: (1) multi-modality imaging for better definition of tumor volume, 2) time-resolved imaging for modeling the intrafraction organ motion. In this presentation, two available imaging techniques will be highlighted, with emphasis on the principle and quality control of multi-modality imaging and moving organ. Multi-modality imaging involves the incorporation of two or more the following imaging modalities: single photon emission computed tomography (SPECT), positron emission tomography (PET), magnetic resonance imaging (MRI), computed tomography (CT) and optical imaging. The incorporation of multi-modality imaging provides functional and anatomic information. Multi-modality imaging is essential for a primary diagnosis and