Mouse Radiation Treatment Center (MRTC)

Preclinical Radiation Studies at the MRTC

We have developed a high-throughput mouse-flank irradiation system that delivers the intended dose to flank xenografts. At the same time, our custom shielding blocks 95-99% of the non-targeted animal (with radiation physics QA). We can efficiently irradiate up to 60 mice per hour with flank xenografts.
The large numbers of animals treated allow for robust statistical analysis of tumor kinetics and outcomes when comparing the effects of radiosensitizing agents. Optionally, tissue can be acquired and stored from multiple xenograft samples at various time points during treatment to enable molecular analysis. See our complete list of PDX and cell lines in the GCCRI Xenograft and Cell Lines Core, or provide your own tumor models.

We have designed our system to deliver any clinically relevant dosing schemes that faithfully recapitulate the clinical experience.

To expedite or simplify radiation studies, large fraction sizes are frequently used in radiotherapy, either in vivo or in vitro (5-20 Gy per fraction). This makes preclinical inferences about the effect of drug synergism difficult and potentially meaningless, given that the radiobiology of standard fractionation (1.5-2 Gy per fraction) is starkly different from that of ablative radiation doses (>8 Gy per fraction).

This is especially valuable for preclinical testing of agents intended for patients undergoing standard fractionation (the majority of definitive cases). Using our treatment delivery and recovery protocols, we can deliver 20-30 Gy (2 Gy per fraction), with a subsequent <2% rate of treatment-related animal loss and a prolonged observation period (3-4 months).

Radiation Dosimetry

Lack of rigidity in requirements for NIST (National Institute for Standards and Technology) traceable dosimetry in vitro and in vivo preclinical reporting has resulted in limited reproducibility between reported dose and biological effect among research laboratories. Our dosimetry protocols ensure accurate and precise dose delivery across experiments and improve translational outcomes.

Reproducibility and consistency in reporting radiation findings can vary up to 42% between institutions.  Our system has been calibrated by medical radiation physicists with three dosimetry methods to ensure accurate dose delivery to the tissues.

Comprehensive list of diagnoses along with patient demographics:

• PDX models_Ped-In Vivo-TP_(v6.2)_St. Jude(2-24)

Genomic information for many samples is available:

• PDX for Childhood Cancer Therapeutics (PCAT) Portal.

View MRTC Publications

Fee Schedules

MRTC Facility Resources.

XRAD 320

IVS Spectrum

SARRP

Stereotaxic Injectors

The XRAD-320 by Precision X is a small animal cabinet x-ray irradiator located in the GCCRI DLAR barrier facility. The unit is equipped with an adjustable collimator. It can be used for cell irradiation and small-animal irradiation, for targeted radiation with appropriate shielding, and for total-body irradiation for bone marrow ablation.

The Xenogen IVIS Spectrum in GCCRI is available for projects conducted through GCCRI’s cores and services. Monitoring of tumors using bioluminescence or fluorescent probes is especially useful in orthotopic models.

The Xstrahl Small Animal Radiation Research Platform (SARRP) located on the UTHSCSA LOSM campus is run by the MRTC core at GCCRI. The SARRP irradiator uses sophisticated multi-beam radiation and CT imaging to deliver precise doses to target organs or tissues, while sparing surrounding structures. The MuriPlan and MuriSlice software, with its SARRP CS control software, calculates, plans, and delivers animal X-ray treatments.

The core has two KOPF stereotaxic injection devices with syringe infusion pumps and digital coordinate measurement displays. The set up uses isoflurane gas anesthesia and is equipped with animal warming stations.

PTW UNIDOS and Ionization Chamber

MRTC Custom Lead Jigs

Phantom Dosimetry

The PTW UNIDOS electrometer, with a PTW reference-class ionization chamber, provides the MRTC with dose-accuracy assurance. This reference chamber is calibrated with traceability to a primary standard.

Lead shielding devices have been carefully designed and built to accommodate up to 5 mice in a consistent placement for accurate radiation dosing to a flank xenograft. Isoflurane anesthesia is used in this setup to achieve rapid induction and recovery. Rigorous dosimetry has been done in the system with medical radiation physicists to ensure accurate dose delivery. A separate device is also available for use with orthotopic brain xenografts.

In addition to using the PTW ion chamber, we have an established protocol with the University of Wisconsin‐Madison Radiation Calibration Laboratory. Using water-equivalent 3-D phantom mice, a TLD dosimeter can be implanted to measure the radiation dose to the target tissue, enabling an accurate study setup.
SOURCE: https://uwmrrc.wisc.edu