is it used in treatment?
It is used for locating tumors, for treating trypanosomiasis and other diseases.
Arsenic
arsenicals such as melarsoprol are still used for the treatment of trypanosomiasis, since although these drugs have the disadvantage of severe toxicity, the disease is almost uniformly fatal if untreated.

Arsenic trioxide has been used in a variety of ways over the past 500 years, most commonly in the treatment of cancer, but also in medications as diverse as Fowler's solution in psoriasis. The US Food and Drug Administration in the year 2000 approved this compound for the treatment of patients with acute promyelocytic leukemia that is resistant to all-trans retinoic acid.

Recently, researchers have been locating tumors using arsenic-74 (a positron emitter). 
what is the difference between sea otters and seals UNANSWERABLE where are such otters found? Along the coasts of northern and eastern North Pacific Ocean. what is its scientific name? "Enhydra lutris" . who are its predators? Orcas, sea lions, bald eagles, great white sharks in the water and coyote s, and bears on land. do these otters have social structures? They tend to rest together in single-sex groups called rafts consisting of 10 to 100 animals. how do they forage? They take short dives to the sea floor, may turn over rocks in search of prey like fish , snails and other organisms. At times it amy also carry a rock in the pouch across its chest to break open shellfish and clams. who is the first person to describe them? Georg Steller. who is he? He was a naturalist. how does sea otter impact the economy? Sea otters are blamed for declines in shellfish harvest. However, they help the kelp harvesting industry and also pose as a major tourist attraction. in which religion does the above mentioned fish harvested have dietary restrictions? The Jews and the Seventh-day Adventists. mention a few toxic contents in it? Arsenic and toxins released by dinoflagellate. is the first content a chemical element? Yes, it is.
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Arsenic [SEP] Medical use
During the 18th, 19th, and 20th centuries, a number of arsenic compounds were used as medicines, including arsphenamine (by Paul Ehrlich) and arsenic trioxide (by Thomas Fowler). Arsphenamine, as well as neosalvarsan, was indicated for syphilis, but has been superseded by modern antibiotics. However, arsenicals such as melarsoprol are still used for the treatment of trypanosomiasis, since although these drugs have the disadvantage of severe toxicity, the disease is almost uniformly fatal if untreated. Arsenic trioxide has been used in a variety of ways over the past 500 years, most commonly in the treatment of cancer, but also in medications as diverse as Fowler's solution in psoriasis.