Small Animal Radiation Research Platform: Imaging, Mechanics, Control and Calibration

Matinfar, Mohammad; Gray, Owen; Iordachita, Iulian; Kennedy, Christine; Ford, Eric; Wong, John W.; Taylor, Russell H.; Kazanzides, Peter

doi:10.1007/978-3-540-75759-7_112

Cited by 23 publications

(24 citation statements)

References 14 publications

(13 reference statements)

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“…Preclinical studies aim to highlight the biological mechanisms governing radiotherapy response in many radiation applications. [8][9][10][11] With more complex radiotherapy techniques being investigated comes a need for a high-resolution 3D measurement of dose distributions given by small animal microirradiators such as the X-Rad 225Cx (Precision X-Ray, N. Banford, CT). Current procedures for small animal treatment planning involve obtaining beam-on-time necessary for a prescribed dose from tabulated radiation output factors.…”

Section: Introductionmentioning

confidence: 99%

Investigating the accuracy of microstereotactic‐body‐radiotherapy utilizing anatomically accurate 3D printed rodent‐morphic dosimeters

et al. 2015

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Purpose: Sophisticated small animal irradiators, incorporating cone-beam-CT image-guidance, have recently been developed which enable exploration of the efficacy of advanced radiation treatments in the preclinical setting. Microstereotactic-body-radiation-therapy (microSBRT) is one technique of interest, utilizing field sizes in the range of 1-15 mm. Verification of the accuracy of microSBRT treatment delivery is challenging due to the lack of available methods to comprehensively measure dose distributions in representative phantoms with sufficiently high spatial resolution and in 3 dimensions (3D). This work introduces a potential solution in the form of anatomically accurate rodent-morphic 3D dosimeters compatible with ultrahigh resolution (0.3 mm 3 ) optical computed tomography (optical-CT) dose read-out. Methods: Rodent-morphic dosimeters were produced by 3D-printing molds of rodent anatomy directly from contours defined on x-ray CT data sets of rats and mice, and using these molds to create tissue-equivalent radiochromic 3D dosimeters from Presage. Anatomically accurate spines were incorporated into some dosimeters, by first 3D printing the spine mold, then forming a high-Z bone equivalent spine insert. This spine insert was then set inside the tissue equivalent body mold. The high-Z spinal insert enabled representative cone-beam CT IGRT targeting. On irradiation, a linear radiochromic change in optical-density occurs in the dosimeter, which is proportional to absorbed dose, and was read out using optical-CT in high-resolution (0.5 mm isotropic voxels). Optical-CT data were converted to absolute dose in two ways: (i) using a calibration curve derived from other Presage dosimeters from the same batch, and (ii) by independent measurement of calibrated dose at a point using a novel detector comprised of a yttrium oxide based nanocrystalline scintillator, with a submillimeter active length. A microSBRT spinal treatment was delivered consisting of a 180• continuous arc at 225 kVp with a 20 × 10 mm field size. Dose response was evaluated using both the Presage/optical-CT 3D dosimetry system described above, and independent verification in select planes using EBT2 radiochromic film placed inside rodent-morphic dosimeters that had been sectioned in half. Results: Rodent-morphic 3D dosimeters were successfully produced from Presage radiochromic material by utilizing 3D printed molds of rat CT contours. The dosimeters were found to be compatible with optical-CT dose readout in high-resolution 3D (0.5 mm isotropic voxels) with minimal artifacts or noise. Cone-beam CT image guidance was possible with these dosimeters due to sufficient contrast between high-Z spinal inserts and tissue equivalent Presage material (CNR ∼10 on CBCT images). Dose at isocenter measured with optical-CT was found to agree with nanoscintillator measurement to within 2.8%. Maximum dose in line profiles taken through Presage and film dose slices agreed within 3%, with FWHM measurements through each profile found to agree within 2%. Conclusions: T...

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Section: Introductionmentioning

confidence: 99%

Investigating the accuracy of microstereotactic‐body‐radiotherapy utilizing anatomically accurate 3D printed rodent‐morphic dosimeters

et al. 2015

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“…Simple and complex three dimensional (3D) conformal dose distributions are delivered using a combination of gantry and robotic stage motions. Additional details can be found in [2].…”

Section: System Descriptionmentioning

confidence: 99%

“…2 depicts the two translations that are required to move the target from the image origin to the gantry-specific isocenter. It is assumed that the imaging system calibration (see [2]) aligns the image (CT) and robot coordinate systems, with the Z axis defined by the axis of rotation (θ) and the origin lying along this axis (i.e., X = Y = 0). We define the calibration origin as the point on the axis of rotation that is closest to the beam axis when the gantry is in the horizontal position (ϕ = 0°).…”

Section: Calibration Of Sarrpmentioning

confidence: 99%

“…The SARRP aims to address these issues by providing a platform that can perform highresolution imaging and accurate conformal beam therapy on standard animal models for human cancers [2]. It consists of a kilovoltage x-ray tube mounted on a rotating gantry.…”

Section: Introductionmentioning

confidence: 99%

“…The robot y and z axes then affect only the camera u axis, so it is straightforward to geometrically derive the non-trivial elements of the Jacobian, as shown in Fig. 6, when the xray gantry is positioned α° from vertical: (2) Of course, our controller requires the inverse of this Jacobian. For this simple case, the inverse terms are given by:…”

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confidence: 99%

See 2 more Smart Citations

Precision Radiotherapy for Small Animal Research

Matinfar

Iordachita

Ford

et al. 2008

Medical Image Computing and Computer-Assisted Intervention – MICCAI 2008

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Preclinical research using well characterized small animal models has provided tremendous benefits to medical research, enabling low cost, large scale trials with high statistical significance of observed effects. The goal of the Small Animal Radiation Research Platform (SARRP) is to make those models available for the development and evaluation of novel radiation therapies. SARRP demonstrates the capabilities of delivering high resolution, sub-millimeter, optimally planned conformal radiation with on-board cone-beam CT (CBCT) guidance. The system requires accurate calibration of the x-ray beam for both imaging and radiation treatment. In this paper, we present a novel technique using an x-ray camera for calibration of the treatment beam. This technique does not require precise positioning or calibration of the x-ray camera.

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