Sterilization Methods Flashcards
7 cards from real CTBS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Sterilization Methods flashcards as text
Which radiation dose range is typically used by tissue banks for terminal sterilization of allografts to achieve SAL 10⁻⁶?
Answer: 15–25 kGy
Most tissue banks use doses between 15 and 25 kGy for terminal sterilization, balancing sterility assurance with tissue integrity.
During ETO sterilization, relative humidity inside the chamber is critical because:
Answer: Moisture hydrates spore coat, enabling ETO penetration
Adequate moisture (30–80% RH) is needed to hydrate the spore coat, allowing ETO to penetrate and alkylate cellular components effectively.
A tissue bank switches its radiation sterilization source from Co-60 to e-beam. Which limitation of e-beam must be addressed?
Answer: Limited penetration depth for dense or thick products
E-beam electrons have limited penetration compared to gamma photons, restricting its use to thinner or lower-density tissue configurations.
Which chemical parameter is MOST critical to monitor and control during an ETO sterilization cycle?
Answer: ETO gas concentration, temperature, humidity, and time
ETO efficacy depends on the precise control of gas concentration, temperature, humidity, and exposure time — all four must be within validated ranges.
What does the term 'bioburden' mean in the context of tissue sterilization?
Answer: The total number of viable microorganisms present on a product before sterilization
Bioburden is the total count of viable microorganisms on or in a product before terminal sterilization, used to calculate the required sterilization dose.
Under AATB standards, which type of tissue graft is specifically prohibited from terminal sterilization with high-dose radiation due to loss of osteoinductive properties?
Answer: Demineralized bone matrix (DBM)
High-dose radiation degrades the growth factors and BMP proteins in DBM that are responsible for its osteoinductive activity.
A tissue bank discovers that a validation lot was sterilized at a humidity level below the validated range for ETO. The correct action is:
Answer: Quarantine the lot; humidity is a critical parameter that invalidates the cycle
Humidity is a critical ETO cycle parameter; if it falls outside the validated range, the cycle is invalid and the lot must be quarantined pending investigation.