What you need to understand about this study is that radiation poses a particular risk to structural tissues. A structural tissue is anything where function is dictated by form, such as the cardiovascular system or the nervous system (whose function is largely dependent upon the physical layout of the connections between neurons).

Tissues such as the spleen and the lungs are not considered structural because, while they certainly have a physical configuration that is important, their function is distributed identically, or nearly identically, throughout their structure.

If radiation affects one part of a non-structural tissue, it's function is relatively easily transferred to another area.

This is not true of the cardiovascular system; the function of the aorta, for example, cannot be accomplished by a capillary in the leg.

Radiation beyond the magnetosphere can be understood as mainly a point injury. When the highly-accelerated nucleus of a heavy element, for example, passes through a tissue, it causes local tissue damage. This is more important when the tissue is structural, and even more important when that tissue has a limited capacity for repair.

The Apollo astronauts were only beyond the magnetosphere for two weeks or less. Travel to Mars, or habitation on the moon, will both require far greater radiation exposures.

Shielding from highly-accelerated nuclei is currently impossible because they create secondary radiation in any shielding material that is far worse than the original problem.

Long-duration human space flight beyond the magnetosphere is therefore impossible with current technology, despite the hype. We must develop either strong magnetic shielding or genetic modifications to improve radiation resistance before traveling to Mars, otherwise we will arrive with impaired cognition and other infirmities.

Sorry to be the bearer of bad news.