Patient Preparation and Radiation Protection Guidance for Adult Patients Undergoing Radioiodine Treatment for Thyroid Cancer in the UK

Radioactive iodine is a highly effective treatment for thyroid cancer and has now been used in clinical practice for more than 80 years. In general, the treatment is well tolerated. However, it can be logistically quite complex for patients due to the need to reduce iodine intake and achieve high levels of thyroid-stimulating hormone prior to treatment. Radiation protection precautions must also be taken to protect others from unnecessary radiation exposure following treatment. It has been well documented by thyroid cancer patient support groups that there is significant variation in practice across the UK. It is clear that some patients are being asked to observe unnecessarily burdensome restrictions that make it more difficult for them to tolerate the treatment. At the instigation of these support groups, a multidisciplinary group was assembled to examine the evidence and generate guidance on best practice for the preparation of patients for this treatment and the management of subsequent radiation protection precautions, with a focus on personalising the advice given to individual patients. The guidance includes advice about managing particularly challenging situations, for example treating patients who require haemodialysis. We have also worked together to produce a patient information leaflet covering these issues. We hope that the guidance document and patient information leaflet will assist centres in improving our patients' experience of receiving radioactive iodine. The patient information sheet is available as Supplementary Material to this article.

Can quantitative 18F-FDG PET/CT and serum cytokine analysis differentiate ARVC from cardiac sarcoidosis?

Background

Arrhythmogenic right ventricular cardiomyopathy (ARVC) and Cardiac Sarcoidosis (CS) may both cause malignant arrhythmia and sudden death, but differentiating the two can be difficult.

Purpose

To investigate the role of quantitative FDG PET/CT at distinguishing ARVC from CS, and explore whether addition of an inflammatory panel correlates with PET uptake, aiding diagnosis.

Methods

10 patients with CS, 10 with ARVC were enrolled. Participants were prospectively studied with PET/CT. LV uptake was quantified using software and a 17-segment model, measuring maximum standardised uptake (SUVmax) and mean myocardial uptake, comparing these to a local normal reference range (21 volunteers) using a z-score. Blood levels of IL-1b, IL-6, IL-8, IL10, IL-12p40, MCP-1, TGFb, GRO, TNFa, IFNy, FGF2, PDGF were measured using ELISA, compared with 10 healthy controls.

Results

There were no significant differences in cytokine levels between CS and ARVC; most cytokine levels were higher in CS, except IL-6, IL-8 and MCP-1 in ARVC (Table 1). Increased PET uptake was noted in 1 segment of 1 ARVC patient, and in 1–2 segments of 5 CS patients (z-scores 2.25 SD; 2.15–2.38 SD). No pattern of uptake distinguished ARVC from CS, qualitatively assessing LV polar maps (Figure 1A, B). SUVmax and mean uptake were higher in CS vs. ARVC (p<0.05; p=0.13). No significant correlation between cytokine levels and PET uptake was detected (Figure 1C, D).

Conclusion

Quantitative PET/CT uptake and a blood inflammatory panel did not have utility in differentiating the two conditions in our population. There was generally more PET and serum inflammatory activity in CS.

Funding Acknowledgement

Type of funding source: Public hospital(s). Main funding source(s): NHS Endowments

Comparison of fluorodeoxyglucose uptake in symptomatic carotid artery and stable femoral artery plaques

BACKGROUND

Fluorine-18-labelled fluoroxdeoxyglucose (FDG) positron emission tomography (PET) has been used to evaluate atherosclerotic plaque metabolic activity, and through its uptake by macrophages is believed to have the potential to identify vulnerable plaques. The aims were to compare FDG uptake in carotid plaques from patients who had sustained a recent thromboembolic cerebrovascular event with that in femoral artery plaques from patients with leg ischaemia, and to correlate FDG uptake with the proportion of M1 and M2 macrophages present.

METHODS

Consecutive patients who had carotid endarterectomy for symptomatic, significant carotid stenosis and patients with severe leg ischaemia and significant stenosis of the common femoral artery underwent FDG-PET and histological plaque analysis. The voxel with the greatest activity in the region of interest was calculated using the Patlak method over 60 min. Plaques were dual-stained for CD68, and M1 and M2 macrophage subsets.

RESULTS

There were 29 carotid and 25 femoral artery plaques for study. The maximum dynamic uptake was similar in carotid compared with femoral plaques: median (range) 9·7 (7·1-12·2) versus 10·0 (7·4-16·6) respectively (P = 0·281). CD68 macrophage counts were significantly increased in carotid compared with femoral plaques (39·5 (33·9-50·1) versus 11·5 (7·7-21·3) respectively; P < 0·001), as was the proportion of M1 proinflammatory macrophages. The degree of carotid stenosis correlated with the maximum dynamic FDG uptake (rs  = 0·48, P = 0·008).

CONCLUSION

FDG uptake was no greater in symptomatic carotid plaques than in the less inflammatory femoral plaques. In patients on statin therapy. FDG uptake occurred in areas of significant arterial stenosis, irrespective of the degree of inflammation.

EANM/ESC procedural guidelines for myocardial perfusion imaging in nuclear cardiology

The European procedural guidelines for radionuclide imaging of myocardial perfusion and viability are presented in 13 sections covering patient information, radiopharmaceuticals, injected activities and dosimetry, stress tests, imaging protocols and acquisition, quality control and reconstruction methods, gated studies and attenuation-scatter compensation, data analysis, reports and image display, and positron emission tomography. If the specific recommendations given could not be based on evidence from original, scientific studies, we tried to express this state-of-art. The guidelines are designed to assist in the practice of performing, interpreting and reporting myocardial perfusion SPET. The guidelines do not discuss clinical indications, benefits or drawbacks of radionuclide myocardial imaging compared to non-nuclear techniques, nor do they cover cost benefit or cost effectiveness.