Citation Nr: 1337335 Decision Date: 11/15/13 Archive Date: 11/26/13 DOCKET NO. 06-28 366A ) DATE ) ) On appeal from the Department of Veterans Affairs Regional Office in St. Petersburg, Florida THE ISSUES Entitlement to service connection for residuals of radiation exposure, to include skin cancer and thrombocytopenia. REPRESENTATION Veteran represented by: Michael R. Viterna, Attorney-at-Law WITNESS AT HEARING ON APPEAL The Veteran ATTORNEY FOR THE BOARD M.W. Kreindler, Counsel INTRODUCTION The Veteran served on active duty from August 1952 to September 1962, and from September 1962 to February 1980. This matter came to the Board of Veterans' Appeals (Board) from an April 2003 rating decision of a Department of Veterans Affairs (VA) Regional Office (RO). In March 2008, the Veteran testified at a hearing before the Board; the transcript is of record. This matter was remanded in April 2008 and August 2010. In April 2012, the Board denied entitlement to service connection for residuals of radiation exposure, to include skin cancer and thrombocytopenia. The Veteran filed a timely appeal to the United States Court of Appeals for Veterans Claims (Court). Pursuant to a January 2013 Joint Motion for Remand, the Court vacated and remanded the Board's April 2012 decision. Please note this appeal has been advanced on the Board's docket pursuant to 38 C.F.R. § 20.900(c) (2012). 38 U.S.C.A. § 7107(a)(2) (West 2002). FINDINGS OF FACT 1. The Veteran was exposed to ionizing radiation per his Record of Occupational Exposure to Ionizing Radiation (DD Form 1141). 2. The Veteran's skin squamous cell carcinoma and thrombocytopenia are not listed as diseases specific to radiation-exposed veterans for presumptive service connection purposes. 3. The Veteran's skin cancer is not objectively shown to have been caused by his level of exposure to radiation in service. 4. Skin cancer, to include squamous cell carcinoma, was first manifested many years after the Veteran's separation from active duty service. 5. Thrombocytopenia was not present during the Veteran's active duty service or for many years after discharge from service, nor is thrombocytopenia otherwise related to active duty, including exposure to ionizing radiation during service. CONCLUSIONS OF LAW 1. Skin cancer was not incurred in or aggravated by active service and may not be presumed to have been incurred therein. 38 U.S.C.A. §§ 1101, 1110, 1112, 1131, 1133, 5107 (West 2002); 38 C.F.R. §§ 3.303, 3.309, 3.311 (2013). 2. Thrombocytopenia was not incurred in or aggravated by active service and may not be presumed to have been incurred therein. 38 U.S.C.A. §§ 1101, 1110, 1112, 1131, 1133, 5107 (West 2002); 38 C.F.R. §§ 3.303, 3.309, 3.311 (2013). REASONS AND BASES FOR FINDINGS AND CONCLUSIONS Under the Veterans Claims Assistance Act (VCAA) of 2000, codified at 38 U.S.C.A. §§ 5100, 5102, 5103, 5103A, 5106, 5107 and 5126; see also 38 C.F.R. §§ 3.102, 3.156(a), and 3.326(a), VA has a duty to notify the claimant of any information and evidence needed to substantiate and complete a claim, and of what part of that evidence is to be provided by the claimant and what part VA will attempt to obtain for the claimant. 38 U.S.C.A. § 5103(a); 38 C.F.R. § 3.159(b)(1); Quartuccio v. Principi, 16 Vet. App. 183, 187 (2002). The Court's decision in Pelegrini v. Principi, 17 Vet. App. 412 (2004), held, in part, that a VCAA notice, as required by 38 U.S.C.A. § 5103(a), must be provided to a claimant before the initial unfavorable agency of original jurisdiction (AOJ) decision on a claim for VA benefits. This decision has since been replaced by Pelegrini v. Principi, 18 Vet. App. 112 (2004), in which the Court continued to recognize that typically a VCAA notice, as required by 38 U.S.C.A. § 5103(a), must be provided to a claimant before the initial unfavorable agency of original jurisdiction (AOJ) decision on a claim for VA benefits. In December 2002, the Veteran was issued VCAA notice with regard to his claim of service connection for skin disability on a direct basis. In September 2006, the Veteran was issued notices with regard to his claim of service connection for skin disability and thrombocytopenia. Collectively, the letters notified the Veteran of what information and evidence is needed to substantiate his claims, as well as what information and evidence must be submitted by the claimant, what information and evidence will be obtained by VA, and the evidence necessary to support a disability rating and effective date. Id.; but see VA O.G.C. Prec. Op. No. 1-2004 (Feb. 24, 2004); see also Dingess v. Nicholson, 19 Vet. App. 473, 491 (2006). Thereafter, the Veteran was issued notice in February 2008 pertaining to the evidence necessary to support a disability rating and effective date. Collectively, the VCAA letters have clearly advised the Veteran of the evidence necessary to substantiate his claims. The Veteran has received all essential notice, has had a meaningful opportunity to participate in the development of his claims, and is not prejudiced by any technical notice deficiency along the way. See Conway v. Principi, 353 F.3d 1369 (Fed. Cir. 2004). In any event, the Veteran has not demonstrated any prejudice with regard to the content of any notice. See Shinseki v. Sanders, 129 S. Ct. 1696 (2009) (Reversing prior case law imposing a presumption of prejudice on any notice deficiency, and clarifying that the burden of showing that an error is harmful, or prejudicial, normally falls upon the party attacking the agency's determination.) See also Mayfield v. Nicholson, 444 F.3d 1328, 1333-34 (Fed. Cir. 2006). As will be discussed in detail below, the provisions of 38 C.F.R. § 3.311 provide for development of claims based on a contention of radiation exposure during active service and post-service development of a radiogenic disease. These provisions do not give rise to a presumption of service connection, but rather establish a procedure for handling claims brought by radiation-exposed veterans. The Veteran's service treatment and personnel records contain the Veteran's Record of Occupational Exposure to Ionizing Radiation (DD Form 1141). The Board acknowledges that the Veteran has challenged the ionizing radiation dose estimate; however, procedures were followed in compliance with § 3.311. In December 2007, the VA Chief Public Health and Environmental Hazards Officer provided an opinion regarding the Veteran's exposure to ionizing radiation and his claimed disabilities. In July 2013, a VHA opinion was proffered with regard to his thrombocytopenia. Thereafter, a VHA opinion was proffered with regard to his skin cancer. The Board finds that VA has complied with the procedures set forth in § 3.309 and § 3.311 for the development of claims based on exposure to ionizing radiation. See Hilkert v. West, 12 Vet. App. 145, 148-50 (1999); aff'd, 232 F.3d 908 (Fed. Cir. 2000). The Board also finds that VA has complied with all assistance provisions of VCAA. The evidence of record contains the Veteran's service treatment records, service personnel records, and post-service treatment records. There is otherwise no indication of relevant, outstanding records which would support the Veteran's claims. 38 U.S.C.A. § 5103A(c); 38 C.F.R. § 3.159(c)(1)-(3). For all the foregoing reasons, the Board concludes that VA's duties to the Veteran have been fulfilled with respect to the issues on appeal. Criteria & Analysis Applicable law provides that service connection will be granted if it is shown that the veteran suffers from disability resulting from an injury suffered or disease contracted in line of duty, or for aggravation of a preexisting injury suffered or disease contracted in line of duty, in the active military, naval, or air service. 38 U.S.C.A. §§ 1110, 1131; 38 C.F.R. § 3.303. That an injury occurred in service alone is not enough; there must be chronic disability resulting from that injury. If there is no showing of a resulting chronic condition during service, then a showing of continuity of symptomatology after service is required to support a finding of chronicity. 38 C.F.R. § 3.303(b). Service connection may also be granted for any disease diagnosed after discharge, when all the evidence, including that pertinent to service, establishes that the disease was incurred in service. 38 C.F.R. § 3.303(d). Service connection for disability that is claimed to be attributable to exposure to ionizing radiation during service can be demonstrated by several different methods. Davis v. Brown, 10 Vet. App. 209, 211 (1997); Rucker v. Brown, 10 Vet. App. 67, 71 (1997). First, there are certain types of cancer that are presumptively service connected, specific to radiation-exposed veterans. 38 U.S.C.A. § 1112(c); 38 C.F.R. § 3.309(d). Second, when a "radiogenic disease" first becomes manifest after service, and it is contended that the disease resulted from exposure to ionizing radiation during service, various development procedures must be undertaken in order to establish whether or not the disease developed as a result of exposure to ionizing radiation. 38 C.F.R. § 3.311(a)(1). Third, even if the claimed disability is not listed as a presumptive disease under 38 C.F.R. § 3.309(d) or as a radiogenic disease under 38 C.F.R. § 3.311, service connection must still be considered under 38 C.F.R. § 3.303(d) in order to determine whether the disease diagnosed after discharge was incurred during active service. See Combee v. Brown, 34 F.3d 1039 (Fed. Cir. 1994). A "radiation-exposed veteran" is defined as either a veteran who while serving on active duty, or an individual who while serving on active duty for training or inactive duty training, participated in a radiation-risk activity. 38 C.F.R. § 3.309(d)(3)(i). "Radiation-risk activity" is defined to mean onsite participation in a test involving the atmospheric detonation of a nuclear device; the occupation of Hiroshima, Japan, or Nagasaki, Japan, by United States forces during the period beginning on August 6, 1945, and ending on July 1, 1946; or internment as a prisoner of war (or service on active duty in Japan immediately following such internment) during World War II which resulted in an opportunity for exposure to ionizing radiation comparable to that of the United States occupational forces in Hiroshima or Nagasaki during the period from August 6, 1945, through July 1, 1946. 38 C.F.R. § 3.309(d)(3)(ii). The Veteran is considered a radiation-exposed veteran, as defined under 3.309(d)(3)(D)(1)(iv)(A), as he had onsite participation during the official operational period of an atmospheric nuclear test, presence at the test site, or performance of official military duties in connection with ships, aircraft or other equipment use in direct support of the nuclear test. His DD Form 1141 reflects that he was exposed to ionizing radiation while serving in Idaho Falls, Idaho, and while serving on the USS Sargo. Diseases specific to radiation-exposed veterans for the purpose of presumptive service connection are the following: (i) leukemia (other than chronic lymphocytic leukemia); (ii) cancer of the thyroid; (iii) cancer of the breast; (iv) cancer of the pharynx; (v) cancer of the esophagus; (vi) cancer of the stomach; (vii) cancer of the small intestine; (viii) cancer of the pancreas; (ix) multiple myeloma; (x) lymphomas (except Hodgkin's disease); (xi) cancer of the bile ducts; (xii) cancer of the gall bladder; (xiii) primary liver cancer (except if cirrhosis or hepatitis B is indicated); (xiv) cancer of the salivary gland; (xv) cancer of the urinary tract; (xvii) cancer of the bone; (xviii) cancer of the brain; (xix) cancer of the colon; (xx) cancer of the lung; and (xxi) cancer of the ovary. 38 C.F.R. § 3.309(d)(2). The Veteran's skin cancer and thrombocytopenia are not identified as diseases for which the presumption of service connection applies, and section 3.309(d) is not for application in this case. As to the second method for establishing service connection, the provisions of 38 C.F.R. § 3.311 provide for development of claims based upon a contention of radiation exposure during active service and post-service development of a radiogenic disease. The purpose of these provisions is to relieve claimants of the burden of having to submit evidence to show that their disease may have been induced by radiation. These provisions do not give rise to a presumption of service connection, but rather establish a procedure for handling claims brought by radiation exposed veterans or their survivors. See Ramey v. Gober, 120 F.3d 1239, 1244 (Fed. Cir. 1997). The governing regulation essentially states that, in all claims in which it is established that a radiogenic disease first became manifest after service, and it is contended that the disease resulted from radiation exposure, a dose assessment will be made. Dose data will be requested from the Department of Defense in claims based upon participation in atmospheric nuclear testing, and claims based upon participation in the American occupation of Hiroshima or Nagasaki, Japan, prior to July 1, 1946. 38 C.F.R. § 3.311(a)(2). In all other claims involving radiation exposure, a request will be made for any available records concerning the veteran's exposure to radiation. These records normally include but may not be limited to the veteran's Record of Occupational Exposure to Ionizing Radiation (DD Form 1141), if maintained, service medical records, and other records which may contain information pertaining to the veteran's radiation dose in service. All such records will be forwarded to the Under Secretary for Health, who will be responsible for preparation of a dose estimate, to the extent feasible, based on available methodologies. For purposes of 38 C.F.R. § 3.311, a "radiogenic disease" is defined as a disease that may be induced by ionizing radiation. 38 C.F.R. § 3.311(b)(2)(i)-(xxiv), (b)(5)(iv). Skin cancer (vii) is a radiogenic disease, and squamous cell carcinoma is a form of skin cancer. 38 C.F.R. § 3.311(b)(2)(i)-(xxiv). Thrombocytopenia, however, is not a radiogenic disease. Id. As detailed, skin cancer is a radiogenic disease, but thrombocytopenia is not considered a "radiogenic disease" per 38 C.F.R. § 3.311(b)(2)(i)-(xxiv). Although thrombocytopenia is not considered a radiogenic disease, in light of the fact that his skin cancer is a radiogenic disease, the provisions of 38 C.F.R. § 3.311(b)(1)(iii) were complied with in obtaining an opinion from the Under Secretary for Benefits with regard to both claimed disabilities. Notwithstanding the above, the claim must also be reviewed to determine whether service connection can be established on a direct basis. See Combee v. Brown, 34 F.3d 1039, 1043-1044 (Fed. Cir. 1994), reversing in part Combee v. Principi, 4 Vet. App. 78 (1993). In other words, the fact that the veteran may not meet the requirements of a presumptive regulation would not in and of itself preclude him from establishing service connection, because he may in the alternative establish service connection by way of proof of actual direct causation. Service treatment records do not reflect treatment for skin cancer or thrombocytopenia. Reports of Medical Examinations conducted in May 1966, October 1973, and July 1976 reflect that his 'skin, lymphatics' were clinically evaluated as normal. An April 1979 Report of Medical Examination reflects a lipoma on the inferior right buttock but no skin cancer. A February 1980 Report of Medical Examination conducted for retirement purposes reflects that he had a mole on the left medial lower thigh but skin cancer was not diagnosed. Post-service medical records reflect that squamous cell carcinoma was initially diagnosed in or about February 1989, approximately nine years after separation from service. Post-service medical records reflect low platelets in 1995, and a March 2005 VA examination report reflects a diagnosis of thrombocytopenia. In March 2005, the Veteran underwent a VA Ionizing Radiation Examination. The examiner noted that since February 1989 the Veteran had skin cancers which were surgically removed. The biopsy showed superficial basal cell carcinoma from left forehead. Since service, he has not been exposed to radiation. The examiner's impressions included several basal cell carcinoma and thrombocytopenia. In May 2005 VA correspondence from the physician to the Veteran, it was explained that the March 2005 VA examination showed, in pertinent part, several basal cell carcinoma and thrombocytopenia (decreased number of platelets). The physician stated that skin cancer and thrombocytopenia are related to ionizing radiation exposure. In December 2007, the Chief Public Health and Environmental Hazards Officer, offered an opinion in response to the Director, Compensation and Pension Service November 2007 opinion request. The physician stated that based on the Veteran's DD Form 1141, it is estimated that he was occupationally exposed to a dose of ionizing radiation during military service of 0.842 rep, rad or r. The physician explained that skin cancer usually has been attributed to ionizing radiation at high doses, e.g. several hundred rads. Excess numbers of basal cell cancers also have been reported in skin which received estimated doses of 9-12 rads in margins of irradiated areas (Health Effects of Exposure to Low Levels of Ionizing Radiation (BEIR V), 1990, pages 325 to 327). An increased risk for basal cell but not squamous cell skin cancers has been seen in atomic bomb survivors (Ron et al., Skin tumor risk among atomic-bomb survivors in Japan, Cancer Causes and Control, Volume 9, 1998, page 395). The risk of malignant melanoma from exposure to ionizing radiation is not clear. Some clinical studies suggest that high radiation-therapy doses may cause this form of skin cancer (Licata et al., Malignant Melanoma and Other Second Cutaneous Malignancies in Cutaneous T-Cell Lymphoma, Archives of Dermatology, April 1995, pages 432-435; Leff and Henkind, Rhabdomyosarcoma and Late Malignant Melanoma of the Orbit, Ophthalmology, Volume 90, 1983, pages 1258-1260). However, national and international publications on radiation risk do not give explicit risk factors for radiation-induced malignant melanomas or state that the association is equivocal. These reports are based on large epidemiological studies [National Committee on Radiation Protection and Measurements reports 104 (1990) and 115 (1993); International Commission on Radiological Protection publications 59 (1992) and 60 (1991); BEIR V, (1990)]. Among Japanese atomic bomb survivors, a large excess relative risk point estimate for malignant melanomas was found but this was statistically nonsignificant and the confidence interval was extremely wide (Ron et al., pages 393 and 395). A review and meta-analysis found evidence, although inconclusive, of an association between ionizing radiation exposure and melanoma (Fink and Bates, Melanoma and Ionizing Radiation: Is There a Causal Relationship?, Radiation Research, November 2005, pages 701-710). Screening doses were utilized to estimate the likelihood that exposure to ionizing radiation was responsible for the Veteran's skin cancers. These screening doses were derived by the DTRA based on the National Institute for Occupational Safety and Health (NIOSH) version of the Interactive Radioepidemiological Program (IREP) computer software and have been reviewed and confirmed by our office. In accordance with NIOSH IREP guidance, the squamous cell screening doses also can be used for other non-dose or doses corresponding to the specific pathology of the Veteran's skin neoplasm were used. Doses that equal or exceed the applicable screening doses correspond to calculated 99th percentile probability of causation values of 50.00 % or more. The dose reported for the Veteran is less than the applicable screening doses on the attached tables. The NIOSH IREP does not address thrombocytopenia. Damage to the bone marrow other than neoplastic transformation, if caused by radiation, would be an example of a deterministic effect. Deterministic changes generally are considered to have a threshold. The probability of causing harm in most healthy individuals at doses of less than 10 rem as a result of deterministic effects is close to zero (Institute of Medicine Report, Adverse Reproductive Outcomes in Families of Atomic Veterans: The Feasibility of Epidemiologic Studies, 1995, pages 23-24). Usually a threshold dose on the order of hundreds or thousands of rads must be exceeded for the deterministic effect to be expressed (Agency for Toxic Substances and Disease Registry (ATSDR) Toxicological Profile for Ionizing Radiation, 1999, page 83). The Nuclear Regulatory Commission annual occupational dose limit to any organ or tissue (other than the lens of the eye) is 50 rems. Transient changes in formed elements in the blood can be found after doses of about 50 rads (ATSDR, pages 90-96). In light of the above, it was opined that it is unlikely that the Veteran's individual skin cancers cited in the memorandum and thrombocytopenia can be attributed to occupational exposure to ionizing radiation in service. As a result of this opinion, in December 2007 the Director, Compensation and Pension Service, opined that there is no reasonable possibility that the Veteran's skin cancer and thrombocytopenia can be attributed to occupational exposure to ionizing radiation in service. In June 2010 correspondence from Colleen MacInnis, M.D., a dermatologist, she stated that the Veteran has a history of multiple skin cancers on both sun exposed and non sun exposed areas. He also has by his account a history of radiation exposure from the military service. Dr. MacInnis stated that this distribution of cancers is typical for radiation exposure. In October 2011 correspondence from Dr. MacInnis, it was noted that she had treated the Veteran since March 2010 and had reviewed his records from his prior dermatologist. Dr. MacInnis noted the Veteran's history of ongoing skin cancer occurrences. In his collection of records, Dr. MacInnis saw that the Veteran had worked in a nuclear facility cleaning up nuclear spills, exposing him to ionized radiation. Dr. MacInnis opined that it is more likely that not that the exposure of ionized radiation caused the Veteran's skin cancer along with all the uncommonly large amount of skin cancers he has had throughout his history. In July 2013, a VHA examiner, specifically an attending physician in hematology/oncology, reviewed the Veteran's claims folders. The examiner acknowledged that the Veteran had been exposed to ionizing radiation during active service and that he was found to have isolated thrombocytopenia (low platelets). The examiner noted that it appears that thrombocytopenia is dated back since 1996, when his platelet counts were 105,000. Subsequently his platelets counts remained low normal to mildly low till 2006. In fact in 2006 he had a normal platelet count of 149,000. He always had a normal white blood cell count and hemoglobin level. He had multiple eye surgeries and skin surgeries in the past. He did not have any history of more than unusual bleeding from surgery or trauma. One of the progress notes says his peripheral blood smear shows some large platelets which indicates that his bone marrow was producing normal amount of platelets. Chart review suggests he had very low amount of exposure to radiation while on active duty. Upon review of the relevant literature and the Veteran's medical record, the examiner concluded that his isolated thrombocytopenia is not related to his exposure to ionizing radiation. The examiner explained that if a person's bone marrow is affected by radiation it would be expected to have all three blood cell lines be low which means low white blood cells, hemoglobin and platelets. The examiner stated that it would be very unlikely to have only low platelets. Another VHA examiner, specifically a dermatologist, reviewed the Veteran's claims folders with regard to his claim of service connection for a skin disability. The examiner acknowledged that the Veteran had been exposed to ionizing radiation during active service, and that from 1988 to the present, the Veteran developed several skin cancers, including squamous cell carcinoma, basal cell carcinoma, and dysplastic nevi. He was also treated for benign lesions including a dermatofibroma and seborrheic keratosis. The examiner stated that the issue of whether exposure to ionizing radiation is the cause of skin cancer is complex. The examiner explained that studies have shown that skin cancer, particularly basal cell carcinoma, can be induced by acute exposure to ionizing radiation at doses in the range of one to four Sv, or at doses above four Gy, but not at lower doses. The United Nations Scientific Council on the Effects of Atomic Radiation summarizes the risk of radiogenic skin cancer as follows: "Dose-response patterns have not been accurately estimable to radiogenic skin cancer. If any conclusion is warranted, it is that the skin is susceptible to radiation but that excess cases are not common, especially at doses less than 5-10 Gy (500-1000 rad)." The examiner noted that the Veteran's estimated exposure is 0.842 Rad and is therefore far below the amount show to cause skin cancer. UV radiation is the single most important cause of squamous cell carcinoma and its precursors, as well as of basal cell carcinoma. The Veteran was also exposed to years of UV radiation, and the examiner opined that it is more likely that this exposure played a role in the development of skin cancer. Upon review of the relevant literature and the Veteran's medical records, the examiner concluded that it is not likely that the Veteran's skin cancer is causally related to his exposure to ionizing radiation. Where the Board is presented with conflicting medical evidence, it is free to favor one medical opinion over another, provided it offers an adequate basis for doing so. Evans v. West, 12 Vet. App. 22, 30 (1998); Owens v. Brown, 7 Vet. App. 429, 433 (1995). In this regard, the Board notes that the Federal Circuit and the Court have both specifically rejected the "treating physician rule." See White v. Principi, 243 F.3d 1378 (Fed. Cir. 2001); Guerrieri v. Brown, 4 Vet. App. 467 (1993). Instead, the Court has held that the Board must determine how much weight is to be attached to each medical opinion of record. See Guerrieri v. Brown, 4 Vet. App. 467 (1993). Greater weight may be placed on one medical professional's opinion over another, depending on factors such as reasoning employed by the medical professionals and whether or not, and the extent to which, they reviewed prior clinical records and other evidence. Gabrielson v. Brown, 7 Vet. App. 36 (1994); see also Wensch v. Principi, 15 Vet. App. 362, 367 (2001) (it is not error for the Board to favor the opinion of one competent medical expert over that of another when the Board gives an adequate statement of reasons and bases). Adequate reasons and bases, in short, must be presented if the Board adopts one medical opinion over another. In assessing evidence such as medical opinions, the failure of the physician to provide a basis for his opinion goes to the weight or credibility of the evidence in the adjudication of the merits. See Hernandez-Toyens v. West, 11 Vet. App. 379, 382 (1998). Other factors for assessing the probative value of a medical opinion are the physician's access to the claims file and the thoroughness and detail of the opinion. See Prejean v. West, 13 Vet. 444, 448-9 (2000). In some cases, the physician's special qualifications or expertise in the relevant medical specialty or lack thereof may be a factor. In every case, the Board must support its conclusion with an adequate statement of its reasoning of why it found one medical opinion more persuasive than the other. Upon review of the entire evidence of record, to include the treatment records, lay statements of the Veteran, records of his ionizing radiation exposure, and the private and VA opinions of record, it is clear that the Veteran was exposed to ionizing radiation during his period of active service and that his skin cancer is a radiogenic disease, but the preponderance of the evidence is against a finding that his radiation exposure caused his skin cancer and thrombocytopenia. The Board has determined that the May 2005 VA opinion based on the findings of the March 2005 VA ionizing radiation examination cannot provide the basis for granting service connection for skin cancer and thrombocytopenia. As detailed, the VA physician stated that skin cancer and thrombocytopenia are related to ionizing radiation exposure. There is no indication, however, that this VA examiner reviewed the Veteran's claims folder, to include his DD Form 1141, in conjunction with the examination, thus the examiner had no knowledge of the level of his ionizing radiation exposure. Moreover, the examiner did not provide a rationale for the opinion. See Prejean v. West, 13 Vet. App. 444, 448-49 (2000). Likewise, with regard to the opinion of Dr. MacInnis, such opinion is based solely on the Veteran's post-service medical records reflecting skin cancer and his assertions of ionizing radiation exposure. As above, there is no indication that Dr. MacInnis had access to the claims folder, or had information pertaining to the Veteran's level of ionizing radiation exposure. Moreover, Dr. MacInnis did not provide a rationale for the opinion. Thus, such opinions are entitled to limited probative weight. Such opinions without any supporting rationale, without knowledge of the levels of radiation exposure, or citation to medical study are in stark contrast to the December 2007 VA opinion from the Chief Public Health and Environmental Hazards Officer and the VHA opinions from the hematologist/oncologist and dermatologist, which consisted of a complete review of the claims folder, and reference to pertinent studies pertaining to the association between ionizing radiation exposure and the development of skin cancer and thrombocytopenia. In formulating the opinions, the physicians were aware of the Veteran's levels of exposure to ionizing radiation exposure during his active service based on the DD Form 1141. Opinions were provided in light of such dose estimate. As detailed, the December 2007 opinion essentially cites to studies associating squamous cell carcinoma with radiation exposure. However, essentially the Veteran's radiation dose estimate was lower than the thresholds discussed in the studies. With regard to his thrombocytopenia, the opinion stated that NIOSH IREP does not address this condition but stated that damage to the bone marrow other than neoplastic transformation, if caused by radiation, would be an example of a deterministic effect. It was explained that the probability of causing harm in most healthy individuals at doses of less than 10 rem as a result of deterministic effects is close to zero, and that usually a threshold dose on the order of hundreds or thousands of rads must be exceeded for the deterministic effect to be expressed. Thus, it was opined that it was unlikely that his skin cancers and thrombocytopenia could be attributed to ionizing radiation exposure while in service. Such opinion cites to relevant studies with regard to the probability of the Veteran's skin cancer or thrombocytopenia being due to radiation exposure. Based on the Veteran's dose estimate of radiation exposure, the examiner could not find any medical evidence to support an association between his exposure to radiation and skin cancer and thrombocytopenia. The Board accepts the December 2007 VA opinion as being probative as it contains detailed rationale for the medical conclusions and is based on sound medical principles. See Boggs v. West, 11 Vet. App. 334 (1998). The VHA hematologist/oncologist noted review of the relevant literature and the Veteran's medical records, including the Veteran's dose estimate, and concluded that his thrombocytopenia is not related to his exposure to ionizing radiation during service. The examiner explained that if the bone marrow is affected by radiation then it would be expected to have all three blood cell lines to be low which means low white blood cells, hemoglobin and platelets and it would be unlikely to have only low platelets. The Board accepts this VHA opinion as being probative as it contains detailed rationale for the medical conclusions and is based on sound medical principles. Id. The VHA dermatologist also noted review of the relevant literature and the Veteran's medical records, including the Veteran's dose estimate, and concluded that his skin cancer is not related to his exposure to ionizing radiation during service. While the examiner explained that the issue of whether exposure to ionizing radiation is the cause of skin cancer is complex, the Veteran's estimated radiation exposure is far below the amount shown to cause skin cancer. The examiner explained that UV exposure more likely played a role in the development of skin cancer, rather than ionizing radiation. The Board accepts this VHA opinion as being probative as it contains detailed rationale for the medical conclusions and is based on sound medical principles. Id. The Board has otherwise given consideration to whether the Veteran's skin cancer and thrombocytopenia are directly related to service. As detailed, service treatment records are void of any finding of these disabilities. The first evidence of skin cancer and thrombocytopenia was many years after separation from service. A significant lapse in time between service and post-service medical treatment may be considered as part of the analysis of a service connection claim. Maxson v. Gober, 230 F.3d 1330 (Fed. Cir. 2000). In adjudicating these claims, the Board must assess the Veteran's competence and credibility with respect to his statements and other lay testimony. See Buchanan v. Nicholson, 451 F.3d 1331 (Fed. Cir. 2006); Washington v. Nicholson, 19 Vet. App. 362, 368- 69 (2005). In Barr v. Nicholson, 21 Vet. App. 303 (2007), the Court emphasized that lay testimony is competent if it is limited to matters that the witness has actually observed and is within the realm of the witnesses personal knowledge. See also 38 C.F.R. § 3.159(a)(2) (Competent lay evidence means any evidence not requiring that the proponent have specialized education, training or experience. Lay evidence is competent if it is provided by a person who has knowledge of the facts or circumstances and conveys matters that can be observed and described by a lay person). The Board has considered the Veteran's lay contentions that his skin cancer and thrombocytopenia are a result of exposure to radiation in service. The Board finds that the Veteran is competent to state his recollections of his in-service experiences, and his assertions as to his in-service duties and radiation exposure are credible in light of the documentation of radiation exposure. The Veteran, however, is not competent to assess his levels of radiation exposure, as he does not have the requisite expertise. Likewise, without any medical expertise, the Veteran lacks the competence to relate his condition to his exposure to radiation during service. Thus, any such statements regarding his dose estimates or etiology of his condition are deemed not competent. As the preponderance of the evidence is against the Veteran's claims of service connection for skin cancer and thrombocytopenia, the benefit of the doubt provision does not apply. Service connection for skin cancer and thrombocytopenia are denied. ORDER Entitlement to service connection for residuals of radiation exposure, to include skin cancer and thrombocytopenia, is denied. ____________________________________________ JOAQUIN AGUAYO-PERELES Veterans Law Judge, Board of Veterans' Appeals Department of Veterans Affairs