Can I Bring Air-activated therapeutic heat pad on a Plane to Canada?

According to CATSA guidelines, air-activated therapeutic heat pad: Certain powders and granular materials in your carry-on are limited to a total quantity of 350 ml/g or less (roughly the size of a soda can). There are no exemptions for medical reasons. Attention Certain powders and granular materials may require additional screening, and in some cases, the items may not be permitted. We recommend that permitted powders and granular materials that are not required during your flight be placed in checked baggage. Exemptions on baby food or formula, life-sustaining medication, and sacred or spiritual items may apply.