His medical studies were awarded the Armand Kleefeld Prize and earned him a scholarship from the Belgian American Educational Foundation to continue his research in the United States.

[6] Pecher saw himself faced with a choice between his patriotic duty and his scientific calling, with the complicating factor of American pressure to remain in work in a domain whose military relevance was fully recognized, with all the secrecy that this entails.

W. Wesley Campbell and David M. Greenberg and later Pecher demonstrated using radioactive tracers that calcium is almost entirely stored in the bones with small traces being distributed in the soft tissues.

[13][14] Pecher predicted and then demonstrated that strontium, which belongs to the same group in the periodic table, was absorbed by the human body in a manner similar to calcium.

[15][16][17] His work with strontium-89, a calcium analogue, eventually led to its administration to a terminal patient with osteoblastic metastases from a metastatic carcinoma of the prostate.

[24] The groundbreaking work of Pecher was forgotten for decades due to the classification of information linked to the Manhattan project and the American nuclear weapons program.

[34] SUNSHINE elicited a great deal of controversy when it was revealed that many of the remains sampled were utilized without prior permission from the deceased or from relatives of the dead, which wasn't known until many years later.

[35] The seminal contribution of Pecher on the therapeutic use of 89Sr was “rediscovered” in the United States in 1976 by Marshall Brucer, former Chairman of the Medical Division of Oak Ridge Institute of Nuclear Studies.

[23][36][37] In 1973, two German physicians Nosrat Firusian and Carl G. Schmidt rediscovered, independently from Pecher's work, the therapeutic use of 89Sr for the treatment of incurable pain in patients with neoplastic osseous infiltrations.

[12][41] This palliative treatment for breast and prostate cancers metastatic to the bones was only approved by the Food and Drug Administration in 1993 for use in the US under the commercial name "Metastron", in the form of injectable Strontium Chloride, produced by Amersham International and became the first bone-seeking radiopharmaceutical that came into widespread use.