Answer based on context:

Coming off their road win against the Giants, the Chargers went home for an interconference Duel with the Philadelphia Eagles. In the first quarter, the Chargers took the early lead as quarterback Philip Rivers got a 20-yard touchdown pass to fullback Mike Tolbert. In the second quarter, San Diego increased their lead as running back LaDainian Tomlinson got a 3-yard touchdown run. The Eagles would close out the half as David Akers kicked an 18-yard field goal and a 25-yard field goal. In the third quarter, San Diego increased their lead as Tomlinson made a 20-yard touchdown run. Philadelphia tried to come back as Akers nailed another 25-yard field goal, but the Chargers increased their lead even further as Rivers hooked up with wide receiver Legedu Naanee on a 20-yard touchdown pass. For the fourth quarter, the Eagles tried to close the margin as quarterback Donovan McNabb passed to wide receiver Jeremy Maclin on a 5-yard touchdown pass, followed by a 6-yard touchdown pass to tight end Brent Celek, yet the Chargers hung on for the victory when kicker Nate Kaeding got a 29-yard field goal. With the win, the Chargers improved to 6-3 and their winning streak to 4 games. LaDainian Tomlinson (24 carries, 96 yards, 2 TDs) would surpass Marcus Allen for third place in the NFL's All-Time career touchdown leaders with 146.

How many field goals did Akers have during the first half?
2