Table 3. Top 10 countries by publishing volume.
| Rank | Count | Centrality | Country | PET density | Contribution level |
|---|---|---|---|---|---|
| 1 | 300 | 0.74 | USA | 5.75 | 52.17 |
| 2 | 132 | 0.24 | UK | 1–2 | 66–132 |
| 3 | 81 | 0.02 | Denmark | 8.85 | 9.15 |
| 4 | 51 | 0.17 | Germany | 1–2 | 25.5–51 |
| 5 | 48 | 0.19 | The Netherlands | 5.42 | 8.86 |
| 6 | 40 | 0.06 | China | 0.3 | 133.33 |
| 7 | 31 | 0.06 | Italy | 3.67 | 8.45 |
| 8 | 28 | 0.01 | Japan | 4.71 | 5.94 |
| 9 | 27 | 0.02 | Canada | 1.52 | 17.76 |
| 10 | 27 | 0.01 | South Korea | 3.46 | 7.80 |
PET density refers to the number of PET devices per 1 million population. Contribution level is the ratio of the number of publications in the field by each country to the PET density. PET, positron emission tomography.