Hay, first time mommy anxiety talaga! Honestly, marami sa amin ang nag-commute throughout pregnancy, at yung scanner sa LRT/MRT ay very low-level radiation lang, wala kaming nararamdaman physically, at ang doctors namin ay laging sinasabi na safe siya, lalo na't very minimal exposure lang sa daily commute. One of my mum friends was doing the same thing at 20+ weeks, back and forth every day, at ang baby niya ay perfectly healthy! But if you're really worried about it, it wouldn't hurt to mention it sa OB mo sa next check-up, just so you hear it directly from her and matulog ka ng mahimbing. For now, try not to stress too much, the stress itself is mas harmful sa baby kaysa yung scanner, promise!