Faculty Bibliography

Purpose. We quantify the additional radiation exposure in terms of effective dose incurred by patients in the CT portion of SPECT/CT examinations. Methods. The effective dose from a variety of common nuclear medicine procedures is calculated and summarized. The extra exposure from the CT portion of the examination is summarized by examination and body part. Two hundred forty-eight scans from 221 patients are included in this study. The effective dose from the CT examination is also compared to average background radiation. Results. We found that the extra effective dose is not sufficient to cause deterministic effects. However, the stochastic effects may be significant, especially in patients undergoing numerous follow-up studies. The cumulative effect might increase the radiation exposure compared to patient management with SPECT alone. Conclusions. While the relative increase in radiation exposure associated with SPECT/CT is generally considered acceptable when compared with the benefits to the patient, physicians should make every effort to minimize this effect by using proper technical procedures and educating patients about the exposure they will receive.

Details on the 28-year treatment history of a patient with an endocrine-responsive breast cancer are provided. She was originally diagnosed as having a T1N0M0 cancer after a modified radical mastectomy at age 41. Fifteen years later, in 1998, she presented with hemoptysis and pleuritic chest pain: a 10 cm right atrial tumor and estrogen receptor (ER) positive endobronchial and adjacent lung parenchyma adenocarcinoma were documented. Epithelial markers normalized as she manifested a partial response (PR) lasting 3 years with tamoxifen treatment. From 2001 to 2007 she benefitted from exemestane treatment. Upon progression in the previous lung area and left adrenal, exemestane withdrawal led to transient decrease in markers. Six months later (in July 2008), with growth in her adrenal tumor, laparoscopic adrenalectomy was performed: in addition to ER positivity, the tumor showed Her2 overexpression and amplification. She has subsequently had some control of disease with fulvestrant, letrozole + trastuzumab, and subsequently letrozole + lapatinib. In addition to the chronicity of disease, this history illustrates the expanding range of treatments available for endocrine-responsive breast cancer commensurate to our greater understanding of tumor biology

An 81-year-old woman with renal cell carcinoma (RCC) underwent F-18 FDG PET/CT for staging, which demonstrated intense uptake in a dilated azygos vein, in the inferior vena cava (IVC), and in the known large left RCC. Contrast-enhanced CT of the chest and abdomen obtained in the days following confirmed the presence of tumor thrombus in the dilated azygos system, IVC, and the contiguous left renal vein. This case serves as a reminder that special attention should always be paid to the renal vein, IVC, and adjoining venous drainage pathways for abnormal FDG activity while imaging RCC, as the diagnosis of venous tumor thrombus has important clinical ramifications.

We present the PET/CT findings of hemostatic absorbable gelatin (Gelfoam) in a 41-year-old woman who had hysterectomy and bilateral oophorectomy. CT showed a very low attenuation lesion (-232 HU) in the surgical bed, but PET showed no significant activity.

We present the case of a 61-year-old man who underwent I-123 metaiodobenzylguanidine (MIBG) scintigraphy based on clinical suspicion of pheochromocytoma. The study was nondiagnostic secondary to diffuse muscle uptake. On review of his medications, the patient was found to be taking mirtazapine, a tetracyclic antidepressant (Remeron). We hypothesize that the MIBG biodistribution was altered by mirtazapine-mediated blockade of the presynaptic alpha-2 receptor. To our knowledge, tetracyclic antidepressants have not been previously reported to cause altered biodistribution on I-123 MIBG scans.