Proposal for biochemical dosimeter for prolonged space flights

Area of Science:

• Biochemistry
• Radiation Biology
• Medical Physics

Background:

• Radiation dosimetry traditionally relies on physical, chemical, or biological methods.
• Assessing absorbed radiation dose can be achieved by measuring specific molecule concentrations in body fluids.
• Salivary glands are radiosensitive, making their biomarkers useful for radiation effect evaluation.

Purpose of the Study:

• To investigate the potential of serum amylase and Tissue Polypeptide Antigen (TPA) as biomarkers for radiation dosimetry.
• To correlate changes in these molecules with absorbed radiation doses in patients undergoing radiotherapy.
• To evaluate the feasibility of using these biomarkers for cosmic ray exposure assessment.

Main Methods:

• Monitoring serum amylase activity and TPA levels in patients undergoing head and neck radiotherapy.
• Analyzing dose-response relationships using various radiation doses and fractionation schedules.
• Comparing results with non-irradiated tissues (pancreas) and different species.

Main Results:

• Serum amylase and TPA levels significantly increased within two days post-irradiation, correlating directly with absorbed dose.
• Dose-response curves were linear in a 2-6 Gy range and sigmoid from 0.5-10 Gy.
• Amylase levels were unaffected by pancreatic irradiation, and species-specific effects were noted.

Conclusions:

• Serum amylase and TPA serve as effective biochemical dosimeters for ionizing radiation.
• These biomarkers can quantify absorbed doses in patients, including those treated with iodine-131.
• The ease of measurement suggests potential application for monitoring cosmic ray exposure in astronauts.