Modeling a radiotherapy clinical procedure: total body irradiation

Area of Science:

• Radiation Oncology
• Mathematical Modeling
• Cancer Biology

Background:

• Bone marrow transplantation requires conditioning regimens like total body irradiation (TBI).
• Existing models of radiation cell kinetics need enhancement to accurately predict TBI outcomes in cancer patients.

Purpose of the Study:

• To modify the Jones model of bone marrow radiation cell kinetics to simulate TBI procedures.
• To compare two mathematical models (with and without cellular repair/repopulation) for mimicking TBI outcomes.

Main Methods:

• Modified the Jones model by incorporating mutant and cancerous cell compartments.
• Developed a mathematical framework using differential equations (n+4 equations).
• Analyzed two cases: Model I (no repair/repopulation) and Model II (with repair/repopulation).

Main Results:

• Model I provided a closed-form solution and successfully mimicked expected TBI treatment outcomes.
• Model II required numerical solutions and was viable when cancer cell repopulation was less than normal cell repopulation.
• Both models confirmed the efficacy of standard fractionated TBI protocols (1320 cGy over four days).

Conclusions:

• The modified Jones model, particularly Model I, offers a robust method for simulating TBI.
• Model I presents a simpler approach with fewer parameters for predicting TBI efficacy.
• Findings support the current clinical practice of fractionated TBI as a pre-bone marrow transplant conditioning treatment.