PEDIATRIC PRECLINICAL TESTING PROGRAM

General Questions

What is Ionizing Radiation?

Ionizing radiation consists of subatomic particles or electromagnetic waves that are energetic enough to detach electrons from atoms or molecules, ionizing them.

Two of the most common forms of ionizing radiation are gamma rays and x-rays. Both forms of ionizing radiation are almost identical with exception to their source of origination.

How is Ionizing Radiation Generated?

Ionizing radiation comes from radioactive sources such as cobalt 60 and cesium 137 and non-radioactive sources such as x-ray tubes. Radioactive sources are unstable materials where gamma rays originate from the nucleus. x-rays originate in the electron fields surrounding the nucleus or are machine-produced.

What is Ionizing Radiation Used for?

Because of the penetrating properties of ionizing radiation and their ability to kill microorganisms, ionizing radiation is used to sterilize or reduce the microbial load of many different types of products such as medical devices, packaging, cosmetics, foods, and agricultural products. It is also used to alter the properties of many different polymers through recombination, cross-linkage, and cross scission.

Why use x-ray versus gamma produced Ionizing radiation?

Gamma ionizing radiation is produced by radioactive sources such as cobalt 60 or cesium 137 and is dangerous requiring heavy shielding and high levels of security to protect. The unstable material is constantly decaying and cannot be turned off. x-ray ionizing radiation is produced by a x-ray tube therefore it can be turned off when it is not being used and it requires much less shielding. At the end the of unit’s lifecycle, the unit does not have any radioactive source and therefore does not require the expensive disposal costs associated with radioactive sources that continue to degrade over hundreds of years.

Does the RS 3400 require external cooling?

No, the RS 3400 uses a self-contained water to air exchange system.

Is the RS 3400 Blood Irradiator cleared by the FDA for GVHD?

Yes, the RS 3400 was cleared by the USFDA for marketing for the irradiation of blood for the prevention of graft verses host disease (GVHD).

How does the RS 3400 differ from other x-ray irradiators?

The RS 3400 is designed to have the blood bags rotate around the Quastar™ x-ray emitter using our patented carousel and therefore delivers superior uniformity.
Unlike other x-ray blood irradiators, the RS 3400 is completely self-contained and requires no external water supply for tube cooling.
The RS 3400 is engineered for extreme reliability as it uses the proven Quastar™ x-ray emitter.
The RS 3400 has only ONE x-ray tube and ONE power supply.

How does the RS 3400 differ from a Cs-137 gamma irradiator??

The RS 3400 uses a Rad Source patented Quastar™ x-ray emitter and therefore contains NO radioactive isotopes. It can be turned on and off, similar to a light bulb. As a result, there is no Nuclear Site License, Homeland Security issues, or room shielding requirements.

Abstract:
BACKGROUND:
The Pediatric Preclinical Testing Program (PPTP) has been successfully used to determine the efficacy of novel agents against solid tumors by testing them within a mouse-flank in vivo model. To date, radiation therapy has not been applied to this system. We report on the feasibility and biologic outcomes of a pilot study using alveolar and embryonal rhabdomyosarcoma xenograft lines.

PROCEDURES:
We developed a high-throughput mouse-flank irradiation device that allows the safe delivery of radiotherapy in clinically relevant doses. For our pilot study, two rhabdomyosarcoma xenograft lines from the PPTP, Rh30 (alveolar) and Rh18 (embryonal) were selected. Using established methods, xenografts were implanted, grown to appropriate volumes, and were subjected to fractionated radiotherapy. Tumor response-rates, growth kinetics, and event-free survival time were measured.

RESULTS:
Once optimized, the rate of acute toxicity requiring early removal from study in 93 mice was only 3%. During the optimization phase, it was observed that the alveolar Rh30 xenograft line demonstrated a significantly greater radiation resistance than embryonal Rh18 in vivo. This finding was validated within the standardized 30 Gy treatment phase, resulting in overall treatment failure rates of 10% versus 60% for the embryonal versus alveolar subtype, respectively.

CONCLUSIONS:
Our pilot study demonstrated the feasibility of our device which enables safe, clinically relevant focal radiation delivery to immunocompromised mice. It further recapitulated the expected clinical radiobiology.
Copyright © 2012 Wiley Periodicals, Inc.
PMID: 22692929 [PubMed – indexed for MEDLINE]

Website
https://www.ncbi.nlm.nih.gov/pubmed/22692929

Pediatr Blood Cancer. 2013 Mar;60(3):377-82. doi: 10.1002/pbc.24210. Epub 2012 Jun 12.
The application of radiation therapy to the Pediatric Preclinical Testing Program (PPTP): results of a pilot study in rhabdomyosarcoma.
Kaplon R, Hadziahmetovic M, Sommerfeld J, Bondra K, Lu L, Leasure J, Nguyen P, McHugh K, Li N, Chronowski C, Sebastian N, Singh M, Kurmasheva R, Houghton P, Pelloski CE.
Source
Wexner Medical Center at The Ohio State University, Arthur G. James Comprehensive Cancer Center and Richard L. Solove Research Institute, Columbus, Ohio 43210-1280, USA.