This is a multi-centre, open-label, single-arm, Phase 2 study designed to evaluate the diagnostic performance of [68Ga]BED003 in detecting colorectal cancer (CRC), gastric cancer (GC), pancreatic ductal adenocarcinoma (PDAC), invasive lobular breast cancer (ILC), and epithelial ovarian cancer (EOC).

Inclusion Criteria:

1. Participants provide informed consent and confirm that they are able and willing to comply with all protocol requirements.

2. Participants must be ≥ 18 years and < 80 years of age and competent to give informed consent.

3. Eastern Cooperative Oncology Group performance status ≤ 2.

4. Women of childbearing potential (WOCBP) must have a negative serum test at screening and a negative urine pregnancy test at the PET/CT imaging visit (Visit 2) prior to [68Ga]BED003 administration.

   Note: If combining screening (Visit 1) and the PET/CT imaging visit (Visit 2) into a single visit, a serum pregnancy test must be used to exclude pregnancy.

5. WOCBP, and men who are sexually active with WOCBP, must agree to use a highly-effective method(s) of contraception from the PET/CT imaging visit (Day 1/Visit 2) to the safety follow-up telephone call (Day 3/Visit 3).

6. Diagnosis of either CRC (confirmed by histopathology), GC (confirmed by histopathology), PDAC (confirmed by cytology or histopathology), ILC (confirmed by histopathology), or EOC (suspected or confirmed by cytology or histopathology).

   Note: Invasive breast cancer with mixed ductal/lobular histology is permitted.

7. Conventional imaging performed within 8 weeks of screening (Visit 1) and no later than 24 hours before [68Ga]BED003 administration and available for sending to the central imaging vendor, including, at a minimum, a contrast-enhanced CT that includes the abdomen and pelvis.

8. Either:

   1. Treatment-naïve with at least stage IIB disease. Available biopsy sample or scheduled biopsy or surgical resection no later than Day 42. Cytology of the primary lesion is acceptable for participants with PDAC who are not surgical candidates.
   2. Following neoadjuvant therapy (with at least stage IIB disease at initial presentation) with scheduled biopsy or surgical resection no later than Day 42.
   3. Suspected recurrence after definitive therapy.

Exclusion Criteria:

1. Participants administered any radioisotope within 5 physical half-lives prior to [68Ga]BED003 administration.

2. Participants administered any other IMP within 2 weeks or 5 half-lives, whichever is longest, prior to [68Ga]BED003 administration.

3. Participants who have recently received any other contrast agent (< 24 hours for IV agents and < 5 days for oral agents) before the day of [68Ga]BED003 administration.

4. Participants with a history of severe claustrophobia or panic attacks when in confined spaces.

5. Known hypersensitivity to [68Ga]BED003 or any of its constituents.

6. Participants with any medical condition or other circumstances at screening or in their past medical history that, in the opinion of the investigator, compromise obtaining reliable data, achieving study objectives, or study completion, including, but not limited to, the following:

   1. Any other primary cancers that could confound the interpretation of the study results.
   2. Major surgery (such as laparoscopy/laparotomy/thoracotomy) over the 3 months preceding screening that could confound the interpretation of the study results.
   3. Serious, non-healing wound, ulcer, or bone fracture.
   4. Active hepatitis.
   5. Significant cardiac disorders including recent (in last 3 months) myocardial infarction or clinically significant electrocardiogram (ECG) findings.

7. Known diagnosis of an autoimmune or inflammatory disorder that is expected to confound image interpretation per investigator judgement, excluding disorders directly related to the index cancer (e.g. tumour-associated pancreatitis or biliary stasis for PDAC).

8. Medical history of abdomino-pelvic or breast irradiation in the last 3 months.

9. Presence of any current implanted foreign material (e.g. stents, surgical clips) that may confound image interpretation per investigator judgement.

10. Significant renal impairment, defined as an estimated glomerular filtration rate (as determined by the Modification of Diet in Renal Disease formula) below 45 mL/min/1.73m2 or a serum creatinine > 1.5 × the upper limit of normal.

11. Female participants who are breastfeeding, unless the participant commits to pumping breast milk and discarding it from from the PET/CT imaging visit (Day 1/Visit 2) to the safety follow-up telephone call (Day 3/Visit 3).