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dc.contributor.authorMoore, Christopher J
dc.contributor.authorMarchant, Thomas E
dc.contributor.authorAmer, Ali M
dc.date.accessioned2009-07-06T08:46:45Z
dc.date.available2009-07-06T08:46:45Z
dc.date.issued2006-05-07
dc.identifier.citationCone beam CT with zonal filters for simultaneous dose reduction, improved target contrast and automated set-up in radiotherapy. 2006, 51 (9):2191-204 Phys Med Biolen
dc.identifier.issn0031-9155
dc.identifier.pmid16625035
dc.identifier.doi10.1088/0031-9155/51/9/005
dc.identifier.urihttp://hdl.handle.net/10541/72524
dc.description.abstractCone beam CT (CBCT) using a zonal filter is introduced. The aims are reduced concomitant imaging dose to the patient, simultaneous control of body scatter for improved image quality in the tumour target zone and preserved set-up detail for radiotherapy. Aluminium transmission diaphragms added to the CBCT x-ray tube of the Elekta Synergytrade mark linear accelerator produced an unattenuated beam for a central "target zone" and a partially attenuated beam for an outer "set-up zone". Imaging doses and contrast noise ratios (CNR) were measured in a test phantom for transmission diaphragms 12 and 24 mm thick, for 5 and 10 cm long target zones. The effect on automatic registration of zonal CBCT to conventional CT was assessed relative to full-field and lead-collimated images of an anthropomorphic phantom. Doses along the axis of rotation were reduced by up to 50% in both target and set-up zones, and weighted dose (two thirds surface dose plus one third central dose) was reduced by 10-20% for a 10 cm long target zone. CNR increased by up to 15% in zonally filtered CBCT images compared to full-field images. Automatic image registration remained as robust as that with full-field images and was superior to CBCT coned down using lead-collimation. Zonal CBCT significantly reduces imaging dose and is expected to benefit radiotherapy through improved target contrast, required to assess target coverage, and wide-field edge detail, needed for robust automatic measurement of patient set-up error.
dc.language.isoenen
dc.subject.meshEquipment Design
dc.subject.meshEquipment Failure Analysis
dc.subject.meshFiltration
dc.subject.meshHumans
dc.subject.meshRadiographic Image Enhancement
dc.subject.meshRadiometry
dc.subject.meshRadiotherapy Dosage
dc.subject.meshRadiotherapy Planning, Computer-Assisted
dc.subject.meshTomography, Spiral Computed
dc.titleCone beam CT with zonal filters for simultaneous dose reduction, improved target contrast and automated set-up in radiotherapy.en
dc.typeArticleen
dc.contributor.departmentNorth Western Medical Physics, Christie Hospital NHS Trust, Manchester, UK.en
dc.identifier.journalPhysics in Medicine and Biologyen
html.description.abstractCone beam CT (CBCT) using a zonal filter is introduced. The aims are reduced concomitant imaging dose to the patient, simultaneous control of body scatter for improved image quality in the tumour target zone and preserved set-up detail for radiotherapy. Aluminium transmission diaphragms added to the CBCT x-ray tube of the Elekta Synergytrade mark linear accelerator produced an unattenuated beam for a central "target zone" and a partially attenuated beam for an outer "set-up zone". Imaging doses and contrast noise ratios (CNR) were measured in a test phantom for transmission diaphragms 12 and 24 mm thick, for 5 and 10 cm long target zones. The effect on automatic registration of zonal CBCT to conventional CT was assessed relative to full-field and lead-collimated images of an anthropomorphic phantom. Doses along the axis of rotation were reduced by up to 50% in both target and set-up zones, and weighted dose (two thirds surface dose plus one third central dose) was reduced by 10-20% for a 10 cm long target zone. CNR increased by up to 15% in zonally filtered CBCT images compared to full-field images. Automatic image registration remained as robust as that with full-field images and was superior to CBCT coned down using lead-collimation. Zonal CBCT significantly reduces imaging dose and is expected to benefit radiotherapy through improved target contrast, required to assess target coverage, and wide-field edge detail, needed for robust automatic measurement of patient set-up error.


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