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The external beam radiotherapy and Image-guided radiotherapy (2). Somvilai Mayurasakorn , MD. Division of Therapeutic Radiology and Oncology, Faculty of Medicine, Chiang Mai University. Imaging techniques for IGRT. Imaging techniques for IGRT. On-line EPID IGRT. Based on boney landmarks
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The external beam radiotherapy and Image-guided radiotherapy (2) SomvilaiMayurasakorn, MD. Division of Therapeutic Radiology and Oncology, Faculty of Medicine, Chiang Mai University
Imaging techniques for IGRT On-line EPID IGRT • Based on boney landmarks • Reported outcomes of EPID - based IGRT are favorable IJROBP2000; 46:400-506
Imaging techniques for IGRT CyberKnife Real-Time Tumor Tracking (RTRT)
Imaging techniques for IGRT Volumetric X-ray imaging • Kilovoltage fan-beam CT (kV CT) • Kilovoltage cone-beam CT (kV CBCT) • Megavoltage cone-beam CT (MV CBCT) • Megavoltage fan-beam CT (MV CT) • Korreman S, Rasch C, McNair H et al. The European Society of Therapeutic Radiology and Oncology–European Institute of Radiotherapy (ESTRO–EIR) report on 3D CT-based in-room image guidance systems: A practical and technical review and guide.Radiotherapy and Oncology 2010; 94:129–144
Helical Tomotherapy • Concept for Helical Tomotherapy : Since 1993 • Idea proposed by Thomas Rockwell Mackie • Research/Prototype (Univ. of Wisconsin) • First commercial unit installation at Wisconsin (~2002)
Helical Tomotherapy • Helical - radiation rotating around the patient while couch is translating • The patient is moved through the machine as a radiation source rotates through 360° • Tomotherapy – patient is irradiated “slice by slice”
Helical Tomotherapy • A Highly Integrated Platform For IMRT & IGRT • Integrated solution for the combination of IGRT and IMRT
Helical Tomotherapy Benefits from IGRT • Use of imaging (MVCT) immediately before or during treatment • To ensure that the patient and tumor are in the correct position Allows the correction of both random and systematic components of set-up errors Increasing the accuracy of treatment delivery
Helical Tomotherapy Benefits from IMRT • Characterised by steep dose gradients • Delivering higher doses to the tumor • Maintaining acceptable doses to critical OAR • Allow for dose escalation
Helical Tomotherapy IMRT Helical tomotherapy Arc radiation therapy Slice therapy Correction of both random and systematic components of set-up errors • Fixed- gantry • Step and shoot • dynamic The patient is moved throughthe treatment unit while the radiation source rotates around the patient Palma et al. Cancer Treatment Reviews 2010;36 :393–399
Helical Tomotherapy Palma et al. Cancer Treatment Reviews 2010;36 :393–399
Quality Depends on Number of Beams 1 Beam 11 Beams 5 Beams 17 Beams 25 Beams 51 Beams
NPC patient Comparisons of isodose distributions A dosimetric gain in CI and HI of PTV and sparing of OARs was significantly obtained in HT versus SaS-IMRT T.-F. Lee et al. Radiotherapy and Oncology 89 (2008) 89–96
IMRT and HT: The comparison of isodose distributions of PTV and OARs Lee et al.Radiation Oncology 2010 5:58