PubMed · 15112867
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Ramón Abascal García. [Brachytherapy: notable or not able].. https://pubmed.ncbi.nlm.nih.gov/15112867/
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Radioactive holmium-166 loaded poly(L-lactic acid) microspheres are promising systems for the treatment of liver malignancies. The microspheres are loaded with holmium acetylacetonate (HoAcAc) and prepared by a solvent evaporation method. After preparation, the microspheres (Ho-PLLA-MS) are activated by neutron irradiation in a nuclear reactor. In this paper, the aspects of the production of a (relatively) large-scale GMP batch (4 g, suitable for treatment of 5-10 patients) of Ho-PLLA-MS are described. The critical steps of the Ho-PLLA-MS production process (sieving procedure, temperature control during evaporation and raw materials) were considered and the pharmaceutical quality of the microspheres was evaluated. The pharmaceutical characteristics (residual solvents, possible bacterial contaminations and endotoxins) of the produced Ho-PLLA-MS batches were in compliance with the requirements of the European Pharmacopoeia. Moreover, neutron irradiated Ho-PLLA-MS retained their morphological integrity and the holmium remained stably associated with the microspheres; it was observed that after 270h (10 times the half-life of Ho-166) only 0.3+/-0.1% of the loading was released from the microspheres in an aqueous solution. In conclusion, Ho-PLLA-MS which are produced as described in this paper, can be clinically applied, with respect to their pharmaceutical quality.
BACKGROUND AND PURPOSE: To investigate differences in rectal dosimetry between pre-plan ultrasonography (US) and post-implant computed tomography (CT). PATIENTS AND METHODS: Subjects comprised 49 patients who underwent prostate brachytherapy using (125)I seed implants. Prescribed dose was 145Gy to the periphery of the prostate. Differences in rectal dosimetry between pre-plan US and post-implant CT analysis were evaluated. In addition, patients were divided into two groups according to timing of pre-planning (pre-plan group, n=28; intraoperative pre-plan group, n=21), and differences in rectal dosimetry between groups were assessed. RESULTS: The average of volume differences between pre-plan and post-implant analysis (pre-plan minus post-implant analysis) for all patients were follows: -0.08 cm(3) in V60 (volume of rectal wall receiving 60% of prescribed dose); -0.05 cm(3) in V70; -0.16 cm(3) in V80; -0.38 cm(3) in V90; -0.40 cm(3) in V100; -0.32 cm(3) in V110; -0.22 cm(3) in V120; -0.15 cm(3) in V130; -0.10 cm(3) in V140; -0.07 cm(3) in V150; and -0.05 cm(3) in V160. Apparent differences between pre-plan US and post-implant CT in rectal dosimetry were small. However, considering the steep curve of the relationship between tolerable volume and dose, a large actual difference should be assumed. No advantage was identified for the intraoperative pre-plan group. Safe volume to avoid proctitis tended to be smaller on ultrasonography than on CT at 1 month. CONCLUSIONS: The present work shows that direct comparison of CT analysis and pre-plan US is unfavorable due to large differences in these modalities and overestimation of tolerable volume. However, by comprehending the degree of difference, comparison of data from CT analysis with a US pre-plan may be feasible and useful for providing feedback between these modalities.
With a total incidence of ca. 800 per year, oral cavity or oropharyngeal carcinoma represents only a small fraction of the total number of cases of cancer in The Netherlands. In order to achieve as much nationwide uniformity as possible in its diagnosis, treatment, after-care and follow-up, a practice guideline has now been developed. The diagnosis of the primary tumour and the neck, careful clinical examination is complemented by echography, often combined with a biopsy, MRI and CT, while technetium scintigraphy in combination with an orthopantomogram is used to detect invasion of the mandible. The smaller oropharyngeal carcinomas (T1 and T2), surgery and radiotherapy (external therapy or brachytherapy) are equally useful, but for the larger carcinomas (T3 and T4) in patients in good general condition, surgery in combination with radiotherapy is preferred. When radiotherapy is chosen, then brachytherapy is preferred for the smaller tumours of the tongue and the floor of the mouth. In patients without demonstrable metastases to the lymph nodes, just as in the case oforopharyngeal carcinomas, the decision whether or not to treat the neck depends on the chances that cervical lymph node metastases are present: when the risk is smaller than 20% (as with smaller tumours), then a wait-and-see policy is justified, but if the risk is greater than 20% (as with larger tumours or very thick rumours), then the neck should be treated, either surgically or by radiotherapy. The practice guideline also contains information regarding decision making, information and communication, palliative therapy and symptomatic treatment, psychosocial assistance, prosthetic reconstruction, physiotherapy, oral hygiene, nutrition and dietetics, swallowing and speech rehabilitation, and the policy with regard to smoking and alcohol consumption.