the majority of cases where there is exposure to ionizing radiation they later develop lymphoblastic leukemia.” This statement is erroneous. The fact is that in those persons exposed to ionizing radiation, some of whom may develop leukemia, the form of leukemia is more commonly myelogenous. CASE NO. 20 Type ofInjury: Acute Lymphatic Leukemia. BVA's Decision: Denial Reversed. Claim was not supported on basis that leukemia was caused by ionizing radiation but compensation granted on grounds that statutory presumptive service connection for leukemia was granted. Dete of Decision: 1970. It is my Opinion that the leukemia from which the veteran died was not service connected. It is further my opinion that he may have had chronic lymphatic leukemia, an insidious and slowly progressive disease with relatively little initial disability, in 1955 or 1956 and that the acute leukemia did not necessarily develop de novo in 1961 but may have been an acute exacerbation of a previously existing and relatively slowly developing chronic lymphatic leukemia. Appellant's Allegation: That veteran’s death from leukemia was a result of Findings of the BVA and Basis for Decision: The Board concluded with resolution of reasonable doubt in favor of the veteran, that leukemia was incurred during the veteran’s active service; was manifested during such service Facts: Veteran served on active duty from June 1954 until June 1957. He died in October 1961 and the cause of his death was certified, after autopsy, as accordingly, that presumptive service connection for leukemia was established. The Board entered the following pertinent findings: service. No dosimetry records existed, however, quantitating the veteran’s 1. The veteran served as a nuclear officer during service but the records do not establish exposure to a significant degree of radioactive substances. 2. A left-sided pain was initially reported in the service records exposure to ionizing radiation during active service. acute lymphatic leukemia. The veteran served as a nuclear officer during exposure to ionizing radiation during his service as a nuclearofficer. Medical Evidence: Leukemia was not diagnosed during the veteran’s active service and no findings specifically diagnostic of leukemia were reported in his service medical records. In the current consideration of the claims, the BVA remanded the case in May 1968 for the purpose of securing further detailed information concerning the extent of the veteran’s exposure to ionizing radiation during service as well as pertinent medical reports and pathologic analyses obtained on postmortem examination. Upon completion of the requested development, the BVA then referred all records and assembled pathologic material to a leading medical school and requested the dean to designate a specialist in the field of pathology and effects of ionizing radiation to study the records and furnish an opinion thereon, The specialist reported as follows: to the degree of ten per cent (10%) within the one year period following the official termination of the Korean conflict on January 31, 1955; and, commencing in June 1955 which, in retrospect, may reasonably be considered indicative of enlargement of the spleen due to leukemia. 3. A differential white blood cell count in March 1956 showed an abnormally high percentage of polymorphonuclear leukocytes and lymphocytes, retrospectively considered strongly suggestive of chronic lymphatic leukemia. 4. Acute lymphatic leukemia was clinically identified and diagnosed early in 1961. 5. The entire record now establishes the reasonable probability that the veteran’s leukemia was in existence during his period of active service. l It is claimed in behalf of [veteran’s] children that the leukemia was related to his exposure to ionizing radiation during his work as a nuclear officer in the Air Force. As a nuclear officer, had he been exposed to radiation, he would have had records quantitating such exposure. No such records exist either at the National Personnel Records Center in St. Louis or at Wright Patterson Base. Hence, it is extremely unlikely that in the course of his work he received any significant radiation, In the record a statement is made by the [appellant’s service] representative that “Modern medical textbooks definitely state that in 68 69