The goal of this clinical trial is to learn if a novel intraoperative fluorescence-guided system (EndoSCell Scanner) can help surgeons more accurately remove all cancerous tissue during breast-conserving surgery in female patients aged 18 years or older, with primary breast cancer. The main questions it aims to answer are:

• Does the use of the EndoSCell Scanner system lower the rate of secondary surgeries needed due to positive cancer margins after the initial operation?
• How accurate is the EndoSCell Scanner system in detecting residual cancer cells on the walls of the surgical cavity during the operation?

Researchers will compare the surgical outcomes using the EndoSCell Scanner guidance to the expected outcomes from standard surgical practice without this technology to see if the system is effective.

Participants will:

• Receive their planned breast-conserving surgery (lumpectomy).
• Have their surgical cavity scanned with the EndoSCell Scanner device after the main tumor is removed.
• Have additional tissue removed from the cavity wall if the scanner indicates a potential cancer residue.

Inclusion Criteria:

1. Pathologically confirmed diagnosis of primary invasive breast cancer, ductal carcinoma in situ (DCIS), or invasive breast cancer with a DCIS component. Acceptable diagnostic methods include core needle biopsy or fine-needle aspiration biopsy.

2. Female, age ≥ 18 years.

3. Scheduled to undergo breast-conserving surgery for the malignant breast lesion.

4. Willing and able to comply with the study procedures and follow-up.

5. Has provided written informed consent.

6. No other uncontrolled serious medical conditions aside from the cancer diagnosis (see Exclusion Criteria for details).

7. Adequate organ and bone marrow function, defined as:

   • White blood cell count > 3,000/μL
   • Platelet count > 75,000/μL
   • Total bilirubin ≤ institutional upper limit of normal (ULN)
   • AST (SGOT) / ALT (SGPT) < 2.5 × institutional ULN
   • Serum creatinine ≤ 1.5 mg/dL, OR creatinine clearance > 60 mL/min/1.73 m² (for participants with serum creatinine levels above institutional ULN)

8. ECOG performance status of 0 or 1.

Exclusion Criteria:

1. Pregnancy or lactation.

2. Suspected pregnancy.

3. Prior injection of ICG or other fluorescent dyes for sentinel lymph node mapping on the day of surgery, before the planned lumpectomy cavity scan with the study device.

4. Unresolved adverse events from previous medications or diagnostic agents.

5. Uncontrolled hypertension, defined as persistent systolic blood pressure > 180 mmHg or diastolic blood pressure > 110 mmHg. Patients with known hypertension must be stable on medication within these limits.

6. History of allergy to any oral or intravenous contrast agent.

7. Uncontrolled comorbidities, including but not limited to:

   • Active infection
   • Symptomatic congestive heart failure
   • Unstable angina pectoris
   • Cardiac arrhythmia
   • Hospitalization for COPD or asthma within the past 12 months
   • Psychiatric illness/social situations that would limit compliance with study requirements.

8. Any condition where, in the investigator's judgment, participation would not be in the best interest of the participant.

9. Planned re-excision lumpectomy due to positive margins from a prior surgery performed before enrollment.

10. Prior surgical history in the ipsilateral breast, including breast cancer surgery, mastectomy, breast reconstruction, or implant placement.