The skeleton is one of the most important human systems that maintains the standing position of the body against the force of gravity. The human skeleton naturally develops in the gravitational field of an earth, and its bony structure is designed to withstand the forces acting on it. The outer layer of bone is called the periosteum (as opposed to the inner layer or endostasis). Peripheral bone tissue is located below the periosteum in the form of bony blades. In the underlying layers, concentric bony ducts (such as the trunk of a tree) surround a blood source, forming the Hawar systems .
Bone tissue is made up of two hard parts of the cortex on the outside, and bone marrow on the inside. The part of the bone that is next to the bone marrow is called the trabecular bone. Compact bone makes up about 80% of the ossification of adults and is mostly found in the trunk of long bones. The spongy or cancellous bone is arranged in parallel microscopic blades and is found mostly in the vertebrae, ribs, pelvis, and ends of long bones.
The arrangement of spongy and dense tissue provides adequate strength for mobility. The spongy part of the bone carries the weight of the body and protects it from fractures. Bone tissue is constantly being rebuilt, and the calcium needed by the body is released intermittently from skeletal stores.
Astronauts who experience prolonged inactivity, such as inpatients, spinal cord amputations, lower extremity paralysis, and those whose limbs remain in a cast for a long time, lose much of their bone mass, bone strength, and muscle strength. Various studies on astronauts show that the loss of bone mass on space missions averages about 1 to 2 percent per month, and the loss of calcium in astronauts is approximately 10 times the amount of calcium lost to women in early menopause. The highest rate of loss of human bone mass on earth).
Decreased bone mass reduces bone strength and increases the risk of fractures, which is one of the current health problems of astronauts and causes them to malfunction on space missions. Osteoporosis in astronauts is one of the biggest obstacles to long-term missions such as traveling to Mars Is. What we have learned about osteoporosis in space will help us better understand this problem, which is a common and debilitating disease on Earth
Scientists have recently found that radiation therapy in cancer patients increases the risk of spontaneous bone fractures, and this fact is a new horizon for researchers. “The risk of bone fractures in postmenopausal women receiving radiation therapy for cervical and colorectal cancer is 60 percent, and in patients with “Anal cancer is increasing by 200 percent.” Since bone loss in astronauts and dealing with solar radiation in space missions to Mars 30 months, provided the inevitable, should circumstances so as to protect passengers against it was .
In the summer of 2006, Bateman exposed 35 female mice to a single (double dose) exposure to high-intensity radiation. Of course, this amount is approximately equal to the intensity of the radiation used for a person with cancer. He divided the mice into four groups, and the effect of different gamma rays (short-wavelength, high-energy electromagnetic waves emitted by radioactive material), protons (components of a positively charged atom about 1836 times larger than an electron).
He examined carbon and ionization (high-power rays with enough energy to take electrons out of the orbit and thus charge the nucleus) on them. The first part of the tibia and femur were examined by CT scan. According to the results, carbon radiation reduced sponge bone mass by 39% (maximum reduction). Proton, ionizing and gamma rays reduced spongy bone mass by 35%, 34% and 29%, respectively.
It is important to note that bone loss is irreversible and does not improve with compensatory therapies. Single ray; Gamma, protons, carbon and ionization in this study were less degraded than the sum of these rays (protons and heavy ions or ionizing rays). This problem was also observed at very low levels of radiation, which was not expected to reduce bone mass. The radiation has no significant effect on the cortex and hard part of the bone and only affects the spongy area. According to the results of this study, spatial radiation intensifies the decrease in bone mass and exacerbates the harmful effects of weight loss on bone.