Sequential measurements of bone lead content by L X-ray fluorescence in CaNa2EDTA-treated lead-toxic children.
With the development of L X-ray fluorescence (LXRF) to measure cortical bone lead directly, safely, rapidly, and noninvasively, the present study was undertaken to a) evaluate LXRF as a possible replacement for the CaNa2EDTA test; b) quantify lead in tibial cortical bones of mildly to moderately lead-toxic children before treatment; and c) quantify lead in tibial cortical bones of lead-toxic children sequentially following one to two courses of chelation therapy. The clinical research design was based upon a longitudinal assessment of 59 untreated lead-toxic children. At enrollment, if the blood lead (PbB) was 25 to 55 micrograms/dL and the erythrocyte protoporphyrin (EP) concentration was greater than or equal to 35 micrograms/dL, LXRF measurement of tibial bone lead was carried out. One day later, each child underwent a CaNa2EDTA provocative test. If this test was positive, lead-toxic children were admitted to the hospital for 5 days of CaNa2EDTA therapy. These tests were repeated 6 weeks and 6 months after enrollment. Abatement of lead paint hazards was achieved in most apartments by the time of initial hospital discharge. The LXRF instrument consists of a low energy X-ray generator with a silver anode, a lithium-doped silicon detector, a polarizer of incident photons, and a multichannel X-ray analyzer. Partially polarized photons are directed at the subcutaneous, medial mid-tibial cortical bone. The LXRF spectrum, measured 90 degrees from the incident beam, reveals a peak in the 10.5 KeV region, which represents the lead L alpha line.(ABSTRACT TRUNCATED AT 250 WORDS)
Rosen
J F
JF
Division of Pediatric Metabolism, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY 10467.
Markowitz
M E
ME
Bijur
P E
PE
Jenks
S T
ST
Wielopolski
L
L
Kalef-Ezra
J A
JA
Slatkin
D N
DN
D001842:Bone and Bones / Q000737:chemistry*; D015913:Chelation Therapy; D002675:Child, Preschool; D004492:Edetic Acid; D006801:Humans; D007854:Lead / Q000032:analysis*; D007855:Lead Poisoning / Q000097:blood / Q000628:therapy*; D008137:Longitudinal Studies; D013052:Spectrometry, X-Ray Emission; D013977:Tibia / Q000737:chemistry
D007854:Lead; D004492:Edetic Acid