Implementation and commissioning of an integrated micro-CT/RT system with computerized independent jaw collimation

Jensen, Michael D.; Hrinivich, William T.; Jung, J; Holdsworth, David W.; Drangova, Maria; Chen, Jeff; Wong, Eugene

doi:10.1118/1.4812422

Cited by 26 publications

(24 citation statements)

References 26 publications

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“…MicroCT imaging on the GE eXplore CT120 scanner is performed with tube voltages between 70 and 120 kVp and radiotherapy with the maximum tube voltage of 120 kVp and tube current of 60 mA, using 1–10 cm diameter circular collimation with ~2 Gy min −1 maximum output. The GE eXplore CT/RT140 microCT imaging is performed in similar fashion to the imager of the GE eXplore CT120 scanner (Jensen et al 2013). Radiotherapy is performed at 140 kVp with a 1.0 mm focal spot with a set of computerized independent jaws and the same SID as the eXplore CT120.…”

Section: Methodsmentioning

confidence: 99%

Multi-institutional MicroCT image comparison of image-guided small animal irradiators

Johnstone¹,

Lindsay²,

Graves³

et al. 2017

Phys. Med. Biol.

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To recommend imaging protocols and establish tolerance levels for microCT image quality assurance (QA) performed on conformal image-guided small animal irradiators. A fully automated QA software SAPA (small animal phantom analyzer) for image analysis of the commercial Shelley micro-CT MCTP 610 phantom was developed, in which quantitative analyses of CT number linearity, signal-to-noise ratio (SNR), uniformity and noise, geometric accuracy, spatial resolution by means of modulation transfer function (MTF), and CT contrast were performed. Phantom microCT scans from eleven institutions acquired with four image-guided small animal irradiator units (including the commercial PXi X-RAD SmART and Xstrahl SARRP systems) with varying parameters used for routine small animal imaging were analyzed. Multi-institutional data sets were compared using SAPA, based on which tolerance levels for each QA test were established and imaging protocols for QA were recommended. By analyzing microCT data from 11 institutions, we established image QA tolerance levels for all image quality tests. CT number linearity set to R2 > 0.990 was acceptable in microCT data acquired at all but three institutions. Acceptable SNR > 36 and noise levels <55 HU were obtained at five of the eleven institutions, where failing scans were acquired with current-exposure time of less than 120 mAs. Acceptable spatial resolution (>1.5 lp mm−1 for MTF = 0.2) was obtained at all but four institutions due to their large image voxel size used (>0.275 mm). Ten of the eleven institutions passed the set QA tolerance for geometric accuracy (<1.5%) and nine of the eleven institutions passed the QA tolerance for contrast (>2000 HU for 30 mgI ml−1). We recommend performing imaging QA with 70 kVp, 1.5 mA, 120 s imaging time, 0.20 mm voxel size, and a frame rate of 5 fps for the PXi X-RAD SmART. For the Xstrahl SARRP, we recommend using 60 kVp, 1.0 mA, 240 s imaging time, 0.20 mm voxel size, and 6 fps. These imaging protocols should result in high quality images that pass the set tolerance levels on all systems. Average SAPA computation time for complete QA analysis for a 0.20 mm voxel, 400 slice Shelley phantom microCT data set was less than 20 s. We present image quality assurance recommendations for image-guided small animal radiotherapy systems that can aid researchers in maintaining high image quality, allowing for spatially precise conformal dose delivery to small animals.

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Section: Methodsmentioning

confidence: 99%

Multi-institutional MicroCT image comparison of image-guided small animal irradiators

Johnstone¹,

Lindsay²,

Graves³

et al. 2017

Phys. Med. Biol.

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“…The dose and time frame were chosen on the basis of a previously published study of the effect of brain irradiation on normal brain in an immune‐competent mouse strain . Radiation delivery was performed using an in‐house custom micro‐irradiation system (140 kVp, 50 kW) with on‐board image guidance . Anesthetized mice were placed in the tail‐first prone position and the skull was located using on‐board fluoroscopy.…”

Section: Methodsmentioning

confidence: 99%

“…Computerized collimators were positioned to create a 10 × 14‐mm 2 field that encompassed the brain and shielded the remainder of the mouse head and body. The whole brain was irradiated using two equal‐weighted, parallel‐opposed beams for a cumulative dose of 10 Gy, as described and validated previously . All irradiated mice received their full 10‐Gy dose and no irradiated mice showed any outward sign of adverse effects caused by the irradiation treatment.…”

Section: Methodsmentioning

confidence: 99%

Cranial irradiation increases tumor growth in experimental breast cancer brain metastasis

Hamilton

Wong

et al. 2018

NMR in Biomedicine

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Whole‐brain radiotherapy is the standard of care for patients with breast cancer with multiple brain metastases and, although this treatment has been essential in the management of existing brain tumors, there are many known negative consequences associated with the irradiation of normal brain tissue. In our study, we used in vivo magnetic resonance imaging analysis to investigate the influence of radiotherapy‐induced damage of healthy brain on the arrest and growth of metastatic breast cancer cells in a mouse model of breast cancer brain metastasis. We observed that irradiated, but otherwise healthy, neural tissue had an increased propensity to support metastatic growth compared with never‐irradiated controls. The elucidation of the impact of irradiation on normal neural tissue could have implications in clinical patient management, particularly in patients with residual systemic disease or with residual radio‐resistant brain cancer.

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“…A similar MicroCT/RT system was designed by the University of Western Ontario and Robarts Research Institute (London, ON, Canada) [162]. Instead of the variable iris aperture collimator, a computerised asymmetric jaw collimator is installed consisting of two orthogonal jaw pairs.…”

Section: Microct/rt Systemmentioning

confidence: 99%

Pre-clinical research in small animals using radiotherapy technology – a bidirectional translational approach

Tillner

Thute

Bütof

et al. 2014

Zeitschrift für Medizinische Physik

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Implementation and commissioning of an integrated micro-CT/RT system with computerized independent jaw collimation

Abstract: A set of computer-controlled motorized jaws for a micro-CT∕RT system were constructed with position reliably better than a tenth of a millimeter. The hardware system is ready for image-guided conformal radiotherapy for small animals with capability of respiratory-gated delivery.

Cited by 26 publications

References 26 publications

Multi-institutional MicroCT image comparison of image-guided small animal irradiators

Multi-institutional MicroCT image comparison of image-guided small animal irradiators

Cranial irradiation increases tumor growth in experimental breast cancer brain metastasis

Pre-clinical research in small animals using radiotherapy technology – a bidirectional translational approach

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