Fast kilovoltage/megavoltage (kVMV) breathhold cone-beam CT for image-guided radiotherapy of lung cancer.

TitleFast kilovoltage/megavoltage (kVMV) breathhold cone-beam CT for image-guided radiotherapy of lung cancer.
Publication TypeJournal Article
Year of Publication2010
AuthorsWertz, H, Stsepankou, D, Blessing, M, Rossi, M, Knox, C, Brown, K, Gros, U, Boda-Heggemann, J, Walter, C, Hesser, J, Lohr, F, Wenz, F
JournalPhysics in medicine and biology
Date Publishedaug
KeywordsCone-Beam Computed Tomography, Cone-Beam Computed Tomography: instrumentation, Cone-Beam Computed Tomography: methods, Humans, Imaging, Lung Neoplasms, Lung Neoplasms: physiopathology, Lung Neoplasms: radiography, Lung Neoplasms: radiotherapy, Phantoms, Radiation Dosage, Respiration, Rotation, Time Factors

Long image acquisition times of 60-120 s for cone-beam CT (CBCT) limit the number of patients with lung cancer who can undergo volume image guidance under breathhold. We developed a low-dose dual-energy kilovoltage-megavoltage-cone-beam CT (kVMV-CBCT) based on a clinical treatment unit reducing imaging time to < or =15 s. Simultaneous kVMV-imaging was achieved by dedicated synchronization hardware controlling the output of the linear accelerator (linac) based on detector panel readout signals, preventing imaging artifacts from interference of the linac's MV-irradiation and panel readouts. Optimization was performed to minimize the imaging dose. Single MV-projections, reconstructed MV-CBCT images and images of simultaneous 90 degrees kV- and 90 degrees MV-CBCT (180 degrees kVMV-CBCT) were acquired with different parameters. Image quality and imaging dose were evaluated and compared to kV-imaging. Hardware-based kVMV synchronization resulted in artifact-free projections. A combined 180 degrees kVMV-CBCT scan with a total MV-dose of 5 monitor units was acquired in 15 s and with sufficient image quality. The resolution was 5-6 line pairs cm(-1) (Catphan phantom). The combined kVMV-scan dose was equivalent to a kV-radiation scan dose of approximately 33 mGy. kVMV-CBCT based on a standard linac is promising and can provide ultra-fast online volume image guidance with low imaging dose and sufficient image quality for fast and accurate patient positioning for patients with lung cancer under breathhold.

Citation Key Wertz2010
PubMed ID20616405