Complex sentence: Additionally, according to Busby, photoelectric enhancement is not limited to radioactive isotopes but involves all heavy atoms (high-Z) "e.g." stable platinum particles from catalytic converters are similarly theoretically capable of enhancing the effects of natural gamma radiation if ingested.
Split into simpler sentences: Additionally, according to Busby, photoelectric enhancement is not limited to radioactive isotopes but involves all heavy atoms (high-Z). For example, in his opinion stable platinum particles emitted from catalytic converters would be similarly capable in theory of enhancing the effects of natural gamma radiation if ingested.