The effects of radiation therapy after implant based reconstruction are really unpredictable. Some women do just fine, whereas some women develop significant scar tissue around the implant. This scar tissue can change the implant's shape and texture or cause pain. Despite this, you should proceed with the radiation. If you have problems afterwards, there are still options even in thin women.
the likelihood of having dissatisfaction with an implant and radiation is between 30 and 50 percent. sounds like you really don't have many options though good luck
Radiation can cause increased risk of capsular contraction and hardness of the skin as well. Sometimes reconstructions have to be revised after this.