Rapid Increase in Utilization Rates of Radionuclide Myocardial Perfusion Imaging and Related Procedures Between 1996 and 1998: What are the Possible Explanations?

No abstract available

Consecutive Case Series of Melanoma Sentinel Node Biopsy for Lymphoseek Compared to Sulfur Colloids

Introduction: Sentinel lymph node biopsy (SLNB) is an important adjunct in the staging of patients with melanoma. Preoperative lymphoscintigraphy (LS) with radiolabeled isotopes is essential to localize sentinel nodes for removal. Our study compared the effectiveness of Lymphoseek to standard sulfur colloids (SC) in patients with melanoma undergoing SLNB. Methods: We queried our IRB-approved melanoma database to identify 370 consecutive patients who underwent SLNB from 2012-2016 with at least one year of follow up. There were 185 patients in each group. Data points included characteristics of the primary melanoma lymphoscintigraphy, and SLNB. Student’s t-test and Chi-Square were used to analyze the data with a p-value of \u3c0.05 being considered significant. Results: Patients were equally matched in regard to age, sex, and primary characteristics of their melanoma. In comparison to SC, Lymphoseek required lower radiation dosages (p\u3c0.001), shorter mapping times (p=0.008), and decreased number of sentinel nodes removed (p=0.03). There was no difference in the number of patients with positive nodes (p=0.5). Additionally, there were no statistical differences between the two radioactive tracers in regard to the number of patients with false negative SLNB. Conclusion: Lymphoseek has the potential to decrease radioactivity and mapping time in patients who need SLNB. With a decrease in the number of nodes removed without loss of sensitivity, there is a potential to avoid unnecessary node removal and thus complications such as lymphedema. Longer follow-up will help to determine if there is any increase in false negative rates despite fewer nodes removed

Altered drainage patterns in patients with melanoma and previous axillary dissection.

The incidence of melanoma is increasing rapidly in the United States. Sentinel lymph node biopsy is an important diagnostic tool in the treatment and staging of melanoma. However, many patients with melanoma will have had lymph node surgery for previous melanoma or breast cancer. We set out to examine alterations in drainage patterns in patients with previous axillary dissection for breast cancer. We reviewed four patients with truncal and/or extremity melanomas and examined their lymphoscintigraphy and drainage patterns. Three patients with truncal melanoma mapped to cervical lymph nodes and a fourth patient with an arm melanoma mapped to her previously dissected axilla. Sentinel lymph node mapping is still an important adjunct in patients with melanoma despite previous axillary dissection

Pathologic Correlation of PET-CT Based Auto Contouring for Radiation Planning in Lung Cancer

Purpose/Objective(s): Radiation therapy in lung cancer relies on CT and functional imaging (FDG-PET) to delineate tumor volumes. Semi-automatic contouring tools have been developed for PET to improve on the inter-observer bias of manual contouring and intrinsic differences in imaging equipment. A common method involves using a threshold at a given percentage of the max activity, which may be less accurate with smaller tumors and tumors with low source to background ratio. To overcome this deficiency, a gradient algorithm, which detects changes in image counts at the border of the tumor, has been developed. Few studies have correlated these methods to pathological specimens. American Society for Therapeutic Radiation Oncology (ASTRO) 52nd Annual Meeting October 31 - November 4, San Diego, C

90Y-clivatuzumab tetraxetan with or without low-dose gemcitabine: A phase Ib study in patients with metastatic pancreatic cancer after two or more prior therapies

AbstractBackgroundFor patients with metastatic pancreatic adenocarcinoma, there are no approved or established treatments beyond the 2nd line. A Phase Ib study of fractionated radioimmunotherapy was undertaken in this setting, administering 90Y-clivatuzumab tetraxetan (yttrium-90-radiolabelled humanised antibody targeting pancreatic adenocarcinoma mucin) with or without low radiosensitising doses of gemcitabine.MethodsFifty-eight patients with three (2–7) median prior treatments were treated on Arm A (N=29, 90Y-clivatuzumab tetraxetan, weekly 6.5mCi/m2doses×3, plus gemcitabine, weekly 200mg/m2 doses×4 starting 1week earlier) or Arm B (N=29, 90Y-clivatuzumab tetraxetan alone, weekly 6.5mCi/m2doses×3), repeating cycles after 4-week delays. Safety was the primary endpoint; efficacy was also evaluated.ResultsCytopaenias (predominantly transient thrombocytopenia) were the only significant toxicities. Fifty-three patients (27 Arm A, 26 Arm B, 91% overall) completed ⩾1 full treatment cycles, with 23 (12 Arm A, 11 Arm B; 40%) receiving multiple cycles, including seven (6 Arm A, 1 Arm B; 12%) given 3–9 cycles. Two patients in Arm A had partial responses by RECIST criteria. Kaplan–Meier overall survival (OS) appeared improved in Arm A versus B (hazard ratio [HR] 0.55, 95% CI: 0.29–0.86; P=0.017, log-rank) and the median OS for Arm A versus Arm B increased to 7.9 versus 3.4months with multiple cycles (HR 0.32, P=0.004), including three patients in Arm A surviving >1year.ConclusionsClinical studies of 90Y-clivatuzumab tetraxetan combined with low-dose gemcitabine appear feasible in metastatic pancreatic cancer patients beyond 2nd line and a Phase III trial of this combination is now underway in this setting

Radiation exposure in X-ray-based imaging techniques used in osteoporosis

Recent advances in medical X-ray imaging have enabled the development of new techniques capable of assessing not only bone quantity but also structure. This article provides (a) a brief review of the current X-ray methods used for quantitative assessment of the skeleton, (b) data on the levels of radiation exposure associated with these methods and (c) information about radiation safety issues. Radiation doses associated with dual-energy X-ray absorptiometry are very low. However, as with any X-ray imaging technique, each particular examination must always be clinically justified. When an examination is justified, the emphasis must be on dose optimisation of imaging protocols. Dose optimisation is more important for paediatric examinations because children are more vulnerable to radiation than adults. Methods based on multi-detector CT (MDCT) are associated with higher radiation doses. New 3D volumetric hip and spine quantitative computed tomography (QCT) techniques and high-resolution MDCT for evaluation of bone structure deliver doses to patients from 1 to 3 mSv. Low-dose protocols are needed to reduce radiation exposure from these methods and minimise associated health risks

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology