SPECT-CT in breast cancer

Abstract

The most important prognostic factors for breast cancer are the size of primary tumor and axillary lymph node status. Role of scintimammography with the cationic lipophilic 99mTc-Tetrofosmin and 99mTc-Sestamibi in preoperative evaluation and post-treatment follow-up of patients with breast cancer is well known. The added diagnostic value of SPECT-CT has recently been investigated. Scintigraphy provides a description of function or process whereas CT depicts the precise localization and type of morphological changes that have occurred in the lesions. Combined SPECT-CT imaging enables to localize positive primary tumors and/or loco-regional lymph nodes; to evaluate effect of neoadjuvant chemotherapy in locally advanced and non-operable breast tumors. SPECT-CT studies are useful in post-therapeutic follow-up of patients to visualize suspicious local recurrence, lymphadenopathy and disease extension. CT part of the study can increase the specificity of SPECT by more accurate anatomical assessment of the sites of abnormal activity with unclear character such as radiation pulmonitis, postoperative parenchymal changes, fibrocystic changes etc. According to the results reported in literature, all the axillary metastatic nodes that were false negative on SPECT image were non-palpable, small lesion size (<10 mm) with partial metastatic involvement or micrometastases in most cases. Lymphatic mapping of SLNs is now routinely done in breast cancer patients for correct N-staging. SPECT-CT has been used for clear depiction of the SLNs to provide the useful information for intraoperative gamma-probe detection in cases that are difficult to interpret planar images, in cases with unusual drainage or in cases of nonvisualization. SPECT-CT scintimammogarphy is preferable in terms of physical characteristic, execution time and cost-effectiveness, thus suggesting wider application of this procedure. SPECT-CT is a potential new tool for LN localization and radioguided surgery in the coming years

Targeting the Oxytocin Receptor for Breast Cancer Management: A Niche for Peptide Tracers

“…57 As an example, SPECT-CT with [ 99m Tc]Tc-MIBI is used for finding proliferative tumoral tissue around a breast implant, in the remaining breast parenchyma, or on the chest wall after surgery. 58 PET imaging is based on detecting annihilation photons produced by the disintegration of positron-emitting radiotracers. 59 The most commonly used radiotracer for the visualization of tumor distribution is [ 18 F]fluorodeoxyglucose ([ 18 F]FDG), a radiolabeled glucose analogue that cancer cells absorb in greater amounts than normal cells due to their increased metabolic activity.…”

“…Typical radiopharmaceuticals used in SPECT imaging of breast cancer include [ 201 Tl]­thalluim­chloride, [ 99m Tc]technetium methoxy­isobutyl­isonitrile ([ 99m Tc]­Tc-MIBI, [ 99m Tc]­Tc-sestamibi), and [ 99m Tc]technetium diphosphonates (Figure ). As an example, SPECT-CT with [ 99m Tc]­Tc-MIBI is used for finding proliferative tumoral tissue around a breast implant, in the remaining breast parenchyma, or on the chest wall after surgery …”

“… 57 As an example, SPECT-CT with [ 99m Tc]Tc-MIBI is used for finding proliferative tumoral tissue around a breast implant, in the remaining breast parenchyma, or on the chest wall after surgery. 58 …”

The role of general nuclear medicine in breast cancer

“…[5][6][7] Technetium-99m (Tc-99m) sestamibi is the radiopharmaceutical of choice for single-photon studies in breast imaging due in part to an overall tumour to background ratio of 6:1. 3,8,9 The recommended administered dose range is 740-1100 MBq (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), resulting in an absorbed dose between 40.0 and 55.5 mGy to the large intestine (critical organ), 20 mGy to the kidney, bladder wall, and gallbladder wall each, and 2 mGy to the breast (lowest dose). 10 An effective dose (a summed entire body exposure estimate that is weighted based on tissue radiosensitivity) was estimated to be 5.9-9.4 mSv compared to 0.44 mSv for digital mammography.…”

“…20 Hybrid SPECT/CT adds clinical value by co-registering physiologic with anatomical data to assist non-palpable lesion biopsies, radiotherapy planning and treatment follow-up. 20,21 Dedicated small field of view (FOV) breast-specific gamma imaging (BSGI) devices have also emerged internationally. 17,[22][23][24] For both scintimammography and BSGI, planar (anterior, lateral, oblique) orientations are obtained 5-15 min post-injection.…”