[en] Full text: Molybdenum-99 is one of the most important radionuclides in modem medicine. When loaded on a chromatographic column it forms a generator that produces high specific activity ^99mTc, a radionuclide widely used in nuclear medical imaging. ANSTO has been a main producer of ⁹⁹Mo in the Australasian region since the late 1960's and currently ranks as one of the major suppliers of ^99mTc/⁹⁹Mo generators. At ANSTO ⁹⁹Mo is produced from enriched uranium oxide (2.2% ²³⁵U) after a nominal seven day irradiation period in HIFAR, Australia's high flux research reactor. Between four and six targets are processed, four to five times each week depending on the reactor operation timetable. After irradiation the targets are allowed to decay for approximately 6 hours before the uranium dioxide pellets are removed and dissolved in a fully enclosed heated vessel equipped with a reflux column. The dissolver off-gas containing noble gases and iodine isotopes released during this process are vented through a caustic scrubber, a number of iodine traps and finally through a charcoal based Noble Gas Trap (NGT). The uranium solution is passed through an alumina column to separate molybdenum from other elements. The ⁹⁹Mo product is eluted from the column with relatively concentrated ammonium hydroxide solution. The product recovery process consists of a volume reduction procedure followed by a recovery step designed to retrieve the product in a minimum volume of dilute nitric acid. The radioactive Xe and Kr discharge was monitored using a Nal(TI) detector based gamma-ray spectrometer system that was interfaced to the internal computer network. The data was collected and sent to the network server at 15-minute intervals using locally written programs that process and database the information. The discharge data is displayed in real time by the use of web browsers found on all networked workstations. The network program is also capable of interrogating the database so that the data could be graphically displayed or retrieved in a spreadsheet format in any combination of time intervals. This option allowed comparison of discharge patterns between process runs and reactor periods as well as yesterday-today comparison to be performed on-line. The use of this software has enabled us to quantify the discharges and identify the process steps that were responsible. This information was used to modify the process, which resulted in a significant reduction in radioactive Xe discharge. These modifications reduced the discharge of short-lived Xe isotopes (¹³⁵Xe and ^135mXe) by approximately 90% and the longer-lived ¹³³Xe discharge by 85%. As the result of this investigation an inventory of all radwaste generated during the separation process was produced. This study enables current and future processing options to be accessed from the viewpoint of waste minimisation and cleaner production. (author)

[en] Purpose/Objective: To test the hypothesis that metastatic cervical lymph nodes arising from nasopharyngeal carcinoma (NPC) are more radiosensitive and radiocurable than comparable nodes originating from squamous cell carcinomas of other head and neck sites. Materials and Methods: A pair-matched historical cohort study involving 104 cases and matched controls was undertaken. Cases of NPC with metastatic cervical nodes were randomly selected from radiation treatment files for the 2 time periods 1969-1976 and 1983-1988 when radiation treatment alone was administered as first line treatment. Controls were randomly selected from radiation treatment files of node positive squamous cell carcinomas arising from the oral cavity, oropharynx, larynx or hypopharynx who were also treated by radical radiation therapy as sole initial treatment in the 1970's and 1980's. Only patients with biopsy proven histology who completed radical radiation treatment were considered for inclusion. The size of the largest involved node (mean 4.1 cm) was used as the sole matching criterion. Results: Despite a similar mean delivered dose to involved nodes (52.9 Gy for the NPC group and 53.9 Gy for the controls) the NPC group exhibited a significantly better nodal control rate after radiation with a 3 year nodal recurrence free rate of 71% compared to 43% among the matched controls (p=0.0002). Conclusion: The results of this study support the hypothesis that metastatic cervical nodes originating from NPC are more radiocurable than similarly sized cervical nodes originating from other head and neck squamous carcinomas. The reasons for this apparent radiosensitivity require further investigation

[en] Applied Waste Research is an approved activity within the ANSTO operational plan. The objective of the activity is to conduct innovative research in radwaste minimisation, develop network based real-time monitoring, develop radwaste inventory and provide a vehicle for the commercialisation of techniques in waste immobilisation. One of the major tasks within the program is to develop real-time monitoring systems for the measurement of noble gas and radioiodine discharges from facilities such as the ⁹⁹Mo production plant. This continues the work initiated under the Waste Management Action Plan project where major gains in radioactive noble gas discharges were made, for example, 85 % reduction in all Xe discharges. (author)

[en] Molybdenum-99 is one of the most important radionuclides in modem medicine. When loaded on a chromatographic column it forms a generator that produces high specific activity ^99mTc, a radionuclide widely used in nuclear medical imaging. ANSTO has been a main producer of ⁹⁹Mo in the Australasian region since the late 1960's and currently ranks as one of the major suppliers of ^99mTc/⁹⁹Mo generators. The dissolver off-gas released during the production process is monitored using a NaI(Tl) detector based gamma-ray spectrometer system that is interfaced to the internal computer network

[en] Short communication. 2 refs

[en] Full text: The development of molecular radiopharmaceuticals is at the cutting edge of nuclear medicine. The somewhat rare facilities and expertise required to produce radiopharmaceuticals capable of detecting abnormalities in receptor densities and metabolic pathways in humans is being established within the Biomedicine and Health Program at ANSTO. One of the radiopharmaceuticals currently synthesised at Lucas Heights for use in a clinical trial labelled with ¹²³l (t_1/2 = 13.3 h) is [¹²³]-iodobenzamide [Parkinson's Disease (Sir Charles Gairdner Hospital) and schizophrenia (Westmead Hospital). Two additional radiopharmaceuticals that are ready to enter clinical trials are [¹²³1]-iodomethyltyrosine (melanoma and brain tumours) and [¹²³]-iodoazomycin arabinoside tissue hypoxia (Fremantle Hospital). Because of the relatively short half-life of ¹²³I, the usual methods of synthesis and formulation of the radiopharmaceuticals have been modified in order to allow the end products to be synthesised in large enough quantities (∼2 GBq) to be shipped to hospitals as far away as Perth (3600 km). These preparations are specially stabilised against the effects of radiolysis to allow them to be shipped over such great distances. All modifications have been optimised and validated, a process which can require up to 150 radiosynthetic experiments for each radiopharmaceutical produced. The modifications developed for large-scale preparation of radiopharmaceuticals for clinical trial, use in Australia will be discussed

No abstract available

[en] An investigation was undertaken to examine responses of mangoes cv. Kensington Pride to irradiation treatment. Gamma irradiation of preclimacteric fruit increased fruit respiration immediately after treatment, delayed the time to attain the climacteric respiratory peak and reduced the magnitude of this peak rate. Fruit softening was unaffected whereas skin colour development was strongly inhibited by irradiation treatment. Inhibition of skin degreening was half-maximal at a dose of 200 Gy. Exposure to ethylene failed to reverse this inhibition. Less mature fruit were more strongly affected by irradiation treatment. Fruit which were partially ripe and in their climacteric rise at time of treatment were largely unaffected by irradiation. These results are discussed in terms of the utility of irradiation technology for commercial disinfestation. (author)

[en] An 11-year-old girl with an arteriovenous malformation (AVM) was referred for Gamma Knife treatment. As this would be the first paediatric treatment in Australia, additional investigations were undertaken into out of field dose to assure the best possible long term outcome for the patient. A phantom was constructed from water equivalent materials to simulate the patient. A target volume was defined to emulate the size and location of the AVM visible in diagnostic images. An ionisation chamber and EBT3 Gafchromic film were used to record absorbed dose at strategic points both on the surface and at depth within the phantom. On the day of treatment, EBT3 Gafchromic film was used to conduct in vivo dosimetry. The pre-treatment phantom measurements matched the planning system for the cranial section (the only modelled section) and no measurable dose above background was detected in the extracranial sites. In vivo measurements of the lenses returned doses of up to 2 cGy for imaging and 8 cGy for treatment which was also consistent with the planned dose. Dose to the thyroid, chest and abdomen was not measurable above background. (paper)

[en] The effects of gamma irradiation and disease control treatments on disease severity and post harvest quality of several mango cultivars were investigated. In mangoes cv. Kensington Pride, irradiation doses ranging from 300-1200 Gy reduced disease, but the level of control was not commercially acceptable. Hot benomyl immediately followed by irradiation provided effective control of anthracnose (Colletotrichum gloeosporioides) and stem end rot (Dothiorella dominicana) during short-term storage (15 days at 20degC). The effects of the two treatments were additive. Satisfactory disease control was achieved during long-term controlled atmosphere storage when mangoes were treated with hot benomyl followed by prochloraz and then irradiated. Effects of fungicide treatment and irradiation were additive. Fungicide, or irradiation treatments alone, were unsatisfactory. Irradiation of cv. Kensington Pride at doses in excess of 600 Gy caused unacceptable surface damage. (author)