Please help me understand this MRI report

Hello everybody. I am new to this forum and so glad I found it. I am actually here because of my mom. She was diagnosed with left breast DCIS last year and went through lumpectomy and 30 sessions of radiation. Also she was found to be BRCA1 positive as well. We have a huge family history of breast and ovarian cancer in her family. I am on a 6 month mammogram/ MRI/ vaginal ultrasound/ CA125 test as well, although hasn't been tested for BRCA yet and hasn't been diagnosed with cancer (NOT YET). Anyways, after my mom completed her radiation in October 2010, her oncologist put her on a 6 month mammo/MRI schedule. She had one mammogram in Feb 2011 which was clean and clear but she had one MRI last week which why I am here today. 2 days after her MRI, we got the call from the nurse saying that she needs to come in for biopsy on her left breast (the same radiated breast) because of a nodule that was seen on MRI. She continued that the radiologist recommendation is to have just an U/S and another 6 month follow up MRI but the oncologist doesn't want to wait 6 months due to her family history and her BRCA situation and she wants her to do the biopsy. So next week she is going for biopsy. I got a copy of the MRI report and here what it says:

Right Breast:

No abnormal contrast enhancement or suspicious mass lesion. 6 mm lobulated nodule at right mid eight o'clock, seen on 7/47. Nodule shows no contrast enhancement and appears bright on gradient echo images and dark on fast spin echo images, consistent with a fibroadenoma. There is a limited fat suppression of the medial and lateral inferior breast. BI-RAD: 2

Left Breast:

4 mm well defined well marginated contrast enhancing nodule at the left mid 3 o'clock, seen on 7/33. On fast spin echo images, the nodule appears signal void and on precontrast it appears isodense. Finding is consistent with a fibroadenoma. Second look ultrasound and six months follow up breast MRI are recommended. BI-RAD 3

Here are my questions:

1-The radiologist's comment for both breasts suggests that finding is "consistent with fibroadenoma". How come he is not concerned about the right breast but he is concerned about the left one? What made the left breast more suspicious than the right one? Why right breast has BIRAD 2 but left one has BI-RAD 3 and biopsy was ordered only on the left one?  

2- Can somebody shed some light and tell me how the left breast nodule looks like? benign/malignant? Do these terms (well defined, well marginated, signal void, isodense) show anything?

3- Is it possible for a breast that was radiated 30 times, to develop another cancer after only 8 months from completion of radiation, given the fact that the first cancer wasn't even invasive (DCIS)? I was told by her oncologist that a radiated breast most likely won't have any recurrence for 5 years.

I appreciate any information. It is so difficult to wait one week to get the biopsy done and few more days to get the result. Thank you all and God bless all of you.