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  • 99mTc-labelled erythrocytes  (1)
  • 99mTc-labelled human serum albumin  (1)
  • Contamination  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Technetium-99m mercaptoalbumin as a potential substitute for technetium-99m labelled red blood cells (1993)
    Springer
    European journal of nuclear medicine 20 (1993), S. 473-482 
    Details
    ISSN: 1619-7089
    Keywords: 99mTc-labelled human serum albumin ; 99mTc-mercaptoalbumin ; Ventriculography ; 99mTc-labelled erythrocytes ; 99mTc-DMP-HSA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Technetium-99m labelled red blood cells (99mTc-RBCs) are far superior to 99mTc-labelled human serum albumin (99mTc-HSA) for radionuclide ventriculography, but their labelling is more complex, time consuming and risk bearing (in vitro labelling) or suffers from interference by some medications (in vivo labelling). We have now modified HSA by the introduction of mercapto groups with the purpose of preparing stable and practical 99mTc-mercaptoalbumin with long retention in the vascular system, that could replace 99mTc-RBCs. HSA was incubated with N-succinimidyl S-acetylthioacetate (SATA) or N-succinimidyl 2,3-di(S-acetylthio) propionate (SATP) to introduce a chain containing one or two protected sulfhydryl groups on some of the lysine amino groups. After purification by size-exclusion chromatography (SEC), the mercapto groups were deprotected by incubation at alkaline pH or by treatment with hydroxylamine. The reaction products were used with or without SEC purification for direct or exchange labelling experiments with 99mTc at neutral pH. SEC-HPLC was used to determine labelling yields and to isolate pure 99mTc-mercaptoalbumin. Stable 99mTc-mercaptoalbumin complexes could be formed in 90%–95% yield after coupling albumin with SATA or SATP in all molar ratios used followed by deacetylation in one of the mentioned conditions. The most favourable results were obtained after reaction of SATA or SATP with HSA in a 25: 1 ratio and deprotection with NH2OH. The stability of the resulting 99mTc-mercaptoacetyl-albumin (99mTc-MAHSA) and 99mTc-dimercaptopropionyl-albumin (99mTcDMP-HSA) and their retention in vivo in plasma of mice and rabbits are clearly higher than that of conventional 99mTc-HSA preparations. 99mTc-DMP-HSA approaches the behaviour of 125I-HSA quite well in both animal species. A preliminary study with 99mTc-DMP-HSA in a volunteer showed a retention in the vascular compartment almost identical to that of 99mTc-RBCs and clearly higher than that of a common 99mTc-HSA preparation. The results indicate that these 99mTc-mercaptoalbumins and especially 99mTc-DMP-HSA are very promising as a practical alternative to 99mTc-RBCs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00175159
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Reduction of contamination risks during clinical studies with Technegas (1999)
    Springer
    European journal of nuclear medicine 26 (1999), S. 1349-1352 
    Details
    ISSN: 1619-7089
    Keywords: Key words: Technegas ; Contamination ; Lung ventilation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. During patient studies with the Technegas equipment in our department, we regularly detected small to considerable contaminations of the operator and in the area surrounding the apparatus. These contaminations were found to be of different origin: residual activity in the tubing from the apparatus to the patient which diffuses after deconnection, residual activity and small particles of the destroyed carbon crucible in the apparatus which are dispersed during opening of the door of the gas preparation chamber, leakage at the patient site during studies in uncooperative patients and a dysfunctioning valve inside the apparatus. To reduce the contamination risks, we made some adaptations to the apparatus. In the first place, the dysfunctioning valve was replaced. In addition, a powerful air exhaust pump with an efficient filter was installed. It was connected with (1) a newly installed transparent box in front of the door of the gas preparation chamber, (2) a dome on a flexible arm which can be positioned above the patient’s face during the examination and (3) a nipple on which the mouthpiece can be placed after the study. After these adaptations, a study showed the absence of measurable contamination on the clothing of the personnel handling the apparatus. Occasionally, considerable contamination was still measured on the gloves worn during filling of the carbon boat with generator eluate, but only small contaminations (up to 9.25 kBq) were measured on the mouthmask worn by the operator during administration of the Technegas. This results in a maximum effective dose equivalent fromactivity deposited in the lungs of 0.008 µSv per study. The total body dose of the operator from external radiation for one Technegas examination was determined to be 2 µSv. The highest dose rate was measured during filling of the crucible (0.2 mSv/h).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002590050594
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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