Cesium-137 in monthly fallout in Tokyo, from 1964 (the year of the first Tokyo Olympic) to 2013, using the data and graph function from Japan Chemical Analysis Center database:
The fallout levels in 1964 look slightly higher than in 2011-2013, except for the initial huge spike in March 2011 due to the Fukushima I Nuclear Power Plant accident. With luck, in 7 years, the fallout levels may come down to 1970s' levels. Even if Cs-134 is included, the order of magnitude doesn't look to increase. (The Y-axis is log.)
As of July 2013, Cs-137 in monthly fallout in Tokyo is 4.4MBq/km2, and Cs-134 is 2.2MBq/km2.
What about strontium, you ask? The maximum amount of strontium-90 in the monthly fallout after the Fukushima I Nuclear Power Plant accident was about half of the fallout after the Chernobyl accident, and close to 1/100 of the maximum 1964 level:
Atmospheric nuclear testing by the United States, the Soviet Union stopped after 1963 Limited Test Ban Treaty, but France, not being a signatory, continued until 1974, and China until 1980.
Some images from 1964 Tokyo Olympic:
Billy Mills (USA), winner of 10,000 long distance run, who overcame prejudice and discrimination (he was a Native American) to win a surprise win in the Olympic (according to Japanese wiki; no such information in English wiki).
Czech gymnast Věra Čáslavská, who enthralled the Japanese and the world viewers.
Ethiopian marathon runner Abebe Bikila, who had run bare-foot in 1960 Rome Olympic; in 1964 Tokyo Olympic, he wore Puma shoes. After the marathon, he said he could easily run another 10 kilometers.
1964 Olympic poster: