DMSA-SPECT: A Novel Approach to Nephron Sparing SBRT for Renal Cell Carcinoma.

PURPOSE: Stereotactic body radiation therapy (SBRT) treatment planning for renal cell carcinoma requires accurate delineation of tumor from normal tissue due to the radiosensitivity of normal renal cortical tissue. Tc-99m dimercapto succinic acid (DMSA) renal imaging is a functional imaging technique that precisely differentiates normal renal cortical tissue from tumor. There are no prior publications reporting using this imaging modality for SBRT treatment planning. METHODS AND MATERIALS: A 59-year-old female with stage IV renal cell carcinoma progressed on systemic therapy and was dispositioned to primary cytoreduction with SBRT. She had baseline renal dysfunction and her tumor was 9 cm without clear delineation from normal tissue on conventional imaging. DMSA-single-photon emission computerized tomography (SPECT)/computed tomography (CT) was used for treatment planning. RESULTS: DMSA-SPECT/CT precisely delineated normal renal cortical tissue from tumor. Three months after treatment, labs were stable and DMSA-SPECT/CT was unchanged. The treated lesion had markedly decreased positron emission tomography avidity. CONCLUSIONS: DMSA-SPECT or SPECT/CT can be incorporated into radiation therapy planning for renal lesions to improve target delineation and better preserve renal function.

The utility of positron emission tomography/computed tomography in target delineation for stereotactic body radiotherapy for liver metastasis from primary gastric cancer: an illustrative case report and literature review.

The liver is a common site for metastatic disease for many cancers. Radiation therapy is one means of treatment for liver metastases, especially for patients unable to undergo surgery or ineligible for systemic chemotherapy. In particular, stereotactic body radiotherapy (SBRT) has become an important option in the treatment of metastatic disease in the liver. SBRT delivers ablative doses of radiation in relatively few fractions. As such, precise and clear imaging plays an important role in maximizing disease control while minimizing normal tissue toxicity. We present a case that highlights the importance of using multiple imaging modalities for target volume delineation in stereotactic radiation treatment of liver metastases.

Imaging of lymph flow in breast cancer patients after microdose administration of a near-infrared fluorophore: feasibility study.

PURPOSE: To prospectively demonstrate the feasibility of using indocyanine green, a near-infrared (NIR) fluorophore at the minimum dose needed for noninvasive optical imaging of lymph nodes (LNs) in breast cancer patients undergoing sentinel lymph node mapping (SLNM). MATERIALS AND METHODS: Informed consent was obtained from 24 women (age range, 30-85 years) who received intradermal subcutaneous injections of 0.31-100 microg indocyanine green in the breast in this IRB-approved, HIPAA-compliant, dose escalation study to find the minimum microdose for imaging. The breast, axilla, and sternum were illuminated with NIR light and the fluorescence generated in the tissue was collected with an NIR-sensitive intensified charged-coupled device. Lymphoscintigraphy was also performed. Resected LNs were evaluated for the presence of radioactivity, blue dye accumulation, and fluorescence. The associations between the resected LNs that were fluorescent and (a) the time elapsed between NIR fluorophore administration and resection and (b) the dosage of NIR fluorophores were tested with the Spearman rank and Pearson product moment correlation tests, respectively. RESULTS: Lymph imaging consistently failed with indocyanine green microdosages between 0.31 and 0.77 microg. When indocyanine green dosages were 10 microg or higher, lymph drainage pathways from the injection site to LNs were imaged in eight of nine women; lymph propulsion was observed in seven of those eight. When propulsion in the breast and axilla regions was present, the mean apparent velocities ranged from 0.08 to 0.32 cm/sec, the time elapsed between "packets" of propelled fluid varied from 14 to 92 seconds. In patients who received 10 microg of indocyanine green or more, a weak negative correlation between the fluorescence status of resected LNs and the time between NIR fluorophore administration and LN resection was found. No statistical association was found between the fluorescence status of resected LNs and the dose of NIR fluorophore. CONCLUSION: NIR fluorescence imaging of lymph function and LNs is feasible in humans at microdoses that would be needed for future molecular imaging of cancer-positive LNs.

Roles of positron emission tomography with fluorine-18-deoxyglucose in the detection of local recurrent and distant metastatic sarcoma.

Sarcomas are a heterogeneous group of tumors comprising approximately 1% of all malignancies. Definitive treatment of sarcoma is surgical resection. However, after surgical removal, 40% to 60% of the patients will develop local or distant recurrence. Therefore, the early detection and treatment of recurrence is an important part of modern sarcoma therapy. Positron emission tomography with fluorine-18-deoxyglucose (FDG-PET) has been highly successful in detecting and staging a variety of malignancies. However, its use in the management of patients with sarcoma is less defined. The purpose of our study was to assess the potential roles of FDG-PET in the detection of local recurrence and distant metastases. In this retrospective study, the images of 33 FDG-PET scans, reports of 29 computed tomography (CT) scans, and 8 magnetic resonance imaging (MRI) scans from 28 patients were compared with surgical pathology or clinical follow up for at least 6 months. FDG-PET detected all 25 cases of local and distant recurrences with 100% sensitivity. CT was able to detect 18 of the 22 possible cases of recurrent disease, whereas MRI was able to detect 5 of 7 cases of recurrent disease. PET was particularly useful in patients with extensive histories of surgery and radiation therapy, precisely the setting in which CT and MRI have the lowest specificity and sensitivity. In conclusion, FDG-PET was a sensitive test to detect local and distant recurrences of sarcoma and this warrants further investigation.

Potential false-positive FDG PET imaging caused by subcutaneous radiotracer infiltration.

Whole-body fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) scanning has been useful in the management of a variety of malignancies with high accuracy. However, numerous nonmalignant lesions can also result in increased FDG accumulation and consequently may cause potential false-positive interpretation if the causes are not recognized. A single focus of FDG accumulation in the axilla can often easily be attributed to tracer infiltration when the injection was on the same side. However, multiple foci of FDG uptake can be similar to malignant lesions. A case is presented in which the follow-up study clarified the nature of multifocal increased FDG uptake in the axilla.

Diffuse bone marrow involvement of Hodgkin lymphoma mimics hematopoietic cytokine-mediated FDG uptake on FDG PET imaging.

Whole-body fluorine-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET) has been useful in the management of a variety of malignancies. In patients with chemotherapy followed by bone marrow stimulants such as granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor, the bone marrow will have diffuse, increased FDG accumulation. Therefore, diffuse bone marrow FDG uptake is commonly attributable to the effect of hematopoietic cytokines. However, diffuse bone marrow FDG uptake can also be caused by bone marrow involvement by malignancy. The authors report a patient with diffuse bone marrow involvement of Hodgkin disease that appears indistinguishable from hematopoietic cytokine-mediated FDG bone marrow uptake.