9. What is a PTC (Patent Co-operation Treaty)?

The Patent Cooperation Treaty (PCT) is an international treaty with more than 150 Contracting States. The PCT makes it possible to seek patent protection for an invention simultaneously in a large number of countries by filing a single “international” patent application instead of filing several separate national or regional patent applications. The granting of patents remains under the control of the national or regional patent offices in what is called the “national phase”.

Member states: https://www.wipo.int/pct/en/pct_contracting_states.html
PCT Timeline: https://www.wipo.int/export/sites/www/pct/en/seminar/basic_1/timeline.pdf