A Collaborative Experience: Implementation of an Optimised Tc-99m Generator Assembly Process

2021 ◽  
Author(s):  
Rijata Sharma ◽  
Bronte Nanette Sial ◽  
Henry Lake ◽  
Prashant Maharaj ◽  
Joshua Reus-Smit ◽  
...  
Keyword(s):  
Half Life ◽  
Assembly Process ◽  
Contamination Control ◽  
Skin Contamination ◽  
Health Products ◽  
Transportation Times ◽  
Exposure Risks ◽  
Skin Doses ◽  
Tissue Reactions ◽  
Contamination Events

Abstract Technetium-99m (Tc-99m) has a six-hour half-life making customer transportation times a challenge. ANSTO (Australia's Nuclear Science and Technology Organisation) Health Products group has overcome this by delivering the parent isotope Molybdenum-99 (Mo-99), which has a half-life of sixty-six hours, in shielded GENTECH™ generators. As part of ANSTO's questioning attitude, an augmented risk assessment was undertaken to identify any potential exposure risks of the GENTECH™ assembly process. The evaluation identified potential areas of improvement in contamination control for the manual handling of the generator leads. Upon further analysis, contamination events from the generator leads had the potential for skin doses above the threshold for skin tissue reactions. Additional substitution and administrative controls were designed to mitigate the risks identified. The effectiveness of the new controls was assessed for efficiency in the manufacturing process through mock trials and fitness for use in a pharmaceutical cleanroom environment. The implemented controls were monitored, and data from each run was gathered. This data included; changes in radiological conditions and dosimetry results. Upon implementation, there was an observable decrease in glove contamination. The decrease verified that there was a reduction in the risk of skin contamination events. The data analysis was used to model the dose averted, which revealed a reduction in potential extremity dose to production workers. This paper aims to show the optimisation within an approved process through the implementation of engineering and administrative controls, resulting in a dose reduction to workers.

New microbiological challenges for the sugar industry with focus on thermophilic acidophilic bacteria

2018 ◽  
pp. 28-32 ◽  
Author(s):  
Christer Bergwall
Keyword(s):  
Production Process ◽  
Sugar Industry ◽  
Sugar Production ◽  
Uv Treatment ◽  
Sugar Factory ◽  
Treatment Techniques ◽  
Acidophilic Bacteria ◽  
Skin Contamination ◽  
Technical Solutions ◽  
Contamination Events

The potential occurrence of guaiacol producing Alicyclobacillus in sugar products and in the sugar production process was evaluated. Final product testing revealed that granulated sugar products showed random background contamination while liquid sugar products were free from guaiacol producing bacteria. Contamination tracing in the sugar factory process showed that beet soil is a primary contamination route to a sugar factory. The bacteria were completely eliminated in the juice purification at all evaluated factories. Random re-contamination was observed in wash syrups from the A-station. Environmental contamination from air and surfaces could not be observed while 20% of human test subjects showed skin contamination of guaiacol producing bacteria. A successful elimination of guaiacol producing bacteria from sugar products was concluded to be unfeasible due to random re-contamination events in the sugar production process. It is suggested that the goal must be to evaluate realistic technical solutions located at the last step of the supply chain. Thermal and non-thermal treatment techniques are available and among those UV-treatment appears to be a promising elimination technique for TAB (thermophilic acidophilic bacteria) and GP-TAB.

The Half-Life of Mindless Psychology

1991 ◽  
Vol 36 (5) ◽  
pp. 455-455
Author(s):  
Michael J. Mahoney
Keyword(s):  
Half Life

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

The Effect of Carbimazole Following Radioiodine Therapy on Radiation Dose to the Thyroid

1981 ◽  
Vol 20 (02) ◽  
pp. 72-75 ◽  
Author(s):  
R. Kocak ◽  
R.G. Herbert ◽  
C.R. Squire ◽  
T.M.D. Gimlette
Keyword(s):  
Thyroid Gland ◽  
Radiation Dose ◽  
Half Life ◽  
Radioiodine Therapy

Radioiodine in the thyroid gland after a therapy dose of 131I was measured serially in 7 patients without Carbimazole, and in 11 patients starting Carbimazole 60 mg daily fourteen days after the therapy dose. Effective half-life for radioiodine in the gland initially 5.53±1.08 days fell to 4.26±1.12 days (p < 0.01) during Carbimazole, and returned to 5.83±1.21 days (NS) after stopping the drug. The radiation dose to the thyroid from a given therapy dose of 131I followed by Carbimazole was calculated to be 97% of that without Carbimazole when the drug was started after 14 days, and 90% and 75% when the drug was started after 7 days and 1 day respectively.

Radiation Mould with Radio Isotope Solutions Fluid „Iso-mould”

1961 ◽  
Vol 1 (03) ◽  
pp. 246-257
Author(s):  
M. O. Roxo-Nobre ◽  
D. M. Vizeu
Keyword(s):  
Clinical Practice ◽  
Remote Control ◽  
Lymph Nodes ◽  
Half Life ◽  
Radioactive Substances

SummaryA technique of mouldage, employing fluid radioactive substances is adopted, to replace the radium-moulding in the treatment of large surfaces. The technique is explained in detail, proving its greater safety by remote control and an adjustment of adequate means of protection. Distribution is obtained by means of a serpentine attached to the mould in question, which follows the Paterson-Parker system. The authors believe the distribution of radiation on curved anatomical areas to be much more uniform by mould system than any other process of application of the same radiation of rectilineal propagation, transmitted at greater focus-skin distances. The isotopes used up to now were the La140 and others of reduced half-life, in order to prevent the danger of eventual contaminations. Although the application of the process still has very little clinical practice, the technique is presented with a view to experimentation in extensive superficial tumours, or those of little depth, such as tumours of the skin, breast, penis, thyrreoid and lymph nodes.

Binding of 131I-Labeled Tissue-Type Plasminogen Activator on De-Endothelialized Lesions in Rabbits

1987 ◽  
Vol 26 (05) ◽  
pp. 224-228 ◽  
Author(s):  
Y. Isaka ◽  
H. Etani ◽  
K. Kimura ◽  
S. Yoneda ◽  
T. Kamada ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Abdominal Aorta ◽  
Half Life ◽  
Balloon Catheter ◽  
Biochemical Properties ◽  
Tissue Type ◽  
Fibrin Deposition ◽  
Tissue Type Plasminogen Activator ◽  
High Affinity ◽  
Type Plasminogen Activator

Tissue-type plasminogen activator (t-PA) which has a high affinity for fibrin in the clot, was labeled with 131I by the iodogen method, and its binding to de-endothelialized lesions in the rabbit was measured to assess the detectability of thrombi. The de-endothelialized lesion was induced in the abdominal aorta with a Fogarty 4F balloon catheter. Two hours after the de-endothelialization, 131I-labeled t-PA (125 ± 46 μCi) was injected intravenously. The initial half-life of the agent in blood (n = 12) was 2.9 ± 0.4 min. The degree of binding of 131I-labeled t-PA to the de-endothelialized lesion was evaluated at 15 min (n = 6) or at 30 min (n = 6) after injection of the agent. In spite of the retention of the biochemical properties of 131I-labeled t-PA and the presence of fibrin deposition at the de-endothelialized lesion, the binding of t-PA to the lesion was not sufficiently strong. Lesion-to-control ratios (cpm/g/cpm/g) were 1.65 ± 0.40 (at 15 min) and 1.39 ± 1.31 (at 30 min), and lesion-to-blood ratios were 1.39 ± 0.32 (at 15 min) and 1.36 ± 0.23 (at 30 min). These results suggest that radiolabeled t-PA may be inappropriate as a radiopharmaceutical for the scintigraphic detection of a pre-existing thrombotic lesion.

Recombinant Variants of Tissue-Type Plasminogen Activator Containing Amino Acid Substitutions in the Finger Domain

1992 ◽  
Vol 68 (06) ◽  
pp. 672-677 ◽  
Author(s):  
Hitoshi Yahara ◽  
Keiji Matsumoto ◽  
Hiroyuki Maruyama ◽  
Tetsuya Nagaoka ◽  
Yasuhiro Ikenaka ◽  
...  
Keyword(s):  
Amino Acid ◽  
Plasminogen Activator ◽  
Half Life ◽  
Tissue Type ◽  
Clot Lysis ◽  
Amino Acid Substitutions ◽  
Wild Type ◽  
Plasma Clot ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator

SummaryTissue-type plasminogen activator (t-PA) is a fibrin-specific agent which has been used to treat acute myocardial infarction. In an attempt to clarify the determinants for its rapid clearance in vivo and high affinity for fibrin clots, we produced five variants containing amino acid substitutions in the finger domain, at amino acid residues 7–9, 10–14, 15–19, 28–33, and 37–42. All the variants had a prolonged half-life and a decreased affinity for fibrin of various degrees. The 37–42 variant demonstrated about a 6-fold longer half-life with a lower affinity for fibrin. Human plasma clot lysis assay estimated the fibrinolytic activity of the 37–42 variant to be 1.4-fold less effective than that of the wild-type rt-PA. In a rabbit jugular vein clot lysis model, doses of 1.0 and 0.15 mg/kg were required for about 70% lysis in the wild-type and 37–42 variant, respectively. Fibrinogen was degraded only when the wild-type rt-PA was administered at a dose of 1.0 mg/kg. These findings suggest that the 37–42 variant can be employed at a lower dosage and that it is a more fibrin-specific thrombolytic agent than the wild-type rt-PA.

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