[en] Short communication

[en] Although widely used in external beam treatment planning, computed tomography scans are infrequent in incranial tumors by implanting of Radioactive isotope. This incranial brachytherapy has only become possible by using CT scans and stereotaxic operation methods. The coincidence of single source and tumor axes in brachytherapy is very important to determine the therapeutic dosages. Even though using the CT scan, according to spatial location of tumor lying, the section of tumor will be seen enlargement, cause the tumor will be cut off with slight angle to its axes. Correct analysis of tumor size from source is required for rotated axes in analytical geometry

[en] An exercise to intercompare the measurement of ¹⁹²Ir brachytherapy sources has been completed and the results indicate that participants were able to measure the air kerma rate (AKR) of the sources with reasonable accuracy. However, it is noted that; (a) 60% of the results can be unequivocally accepted, 11% are rejected as being definitely discrepant; (b) there is a general low bias on the results; (c) there appears to be no particular instrument bias; (d) there needs to be a fuller consideration of measurement uncertainties by the users; (e) there was a wide range of reference data used; and, (f) calibration of the instrumentation relies in many cases, on manufacturer supplied data. It is recommended that the exercise is repeated in the near future, and that the use of thick ('hairpin') wires is included in the next exercise. (author)

[en] Results of 231 patients with squamous cell carcinoma of the lip treated by interstitial brachytherapy from 1968 to 1983 are presented. TNM distribution was T1 83.1%, T2 12.9%, T3 2.1% y T4.1%. Treatment of primary tumors has been interstitial brachytherapy with 192-Ir, as exclusive therapy in 225 cases and in combination with external radiotherapy in 6 cases. Average radiation dose was 75 Gy. Local control has been obtained in 218 patients (94.4%). Salvage treatment in 7 cases of local failure was performed, with a definitive control of 96.9%. These results support the important role of interstitial brachytherapy as therapeutic option for carcinoma of the lip. (Author) 15 refs

[en] The national standard of ¹⁹²Ir Brachytherapy source in terms of reference air kerma rate (RAKR) had been prepared by National Metrology Institute of Japan (NMIJ) in 2015. Following this, the secondary calibration service system of ¹⁹²Ir for limited medical users had been started by Japan Radioisotope Association that is secondary calibration laboratory in Japan. We experimentally carried out the calibration of well-type dosimeter using primary standard source provided by NMIJ

[en] Published in summary form only

[en] A lack of primary standards for HDR 192Ir brachytherapy has been known for years to cause the largest problem in obtaining lower uncertainties in RAKR measurements. The currently used calibration techniques where chambers are calibrated against interim standards, based on interpolation techniques, provide typically an uncertainty of @ 2.5 % (k = 2) in the calibration factor. It constitutes the largest contribution to the total uncertainty in RAKR and may be significantly reduced through the on-going development of primary standards. In this work, RAKR values of 23 HDR 192Ir sources were measured in the department in the past 10 years of clinical HDRBT application. All differences between the measured RAKR and manufacturer's specification were lower than @ 3.5 %. Upon the acceptance of a more rigorous protocol, through which the different variables, such as thermal stability and geometrical reproducibility, have been better controlled during the measurement, these differences dropped to less than @ 2 %. Two ionisation chambers tested in this work showed very good precision, long term stability, small polarity effect and recombination equal to the manufacturer's specification. Differences in repeated measurements of RAKR during the 6 weeks period, in which a source was also changed, were minimal; RAKR-s stayed within 1 %. The calibration technique based on the re-entrant well type chamber is due to its simplicity, speed, accuracy and long term stability a highly recommended option for an institution performing HDR brachytherapy. (author)

[en] Short communication

[en] The brachytherapy in the treatment of rhabdomyosarcomas of the nasogenian groove has to be discussed when it exists a residual tumor after an initial chemotherapy and leads to good results, in term of local control. An advantage of the brachytherapy in comparison with external irradiation, in the treatment of children tumors, is the small size of the treated volume, that allows to decrease the aftereffects incidence. The brachytherapy comes in the frame of a therapeutic needing a multidisciplinary approach and a cooperation between surgeons, brachy-therapists and onco-pediatricians. (N.C.)

[en] Keloids in black patients frequently recur after surgical excision alone. Surgical excision followed by iridium 192 brachytherapy was used to treat 783 keloids in 502 black patients in Martinique. The surgical and radiation therapy technique is described in detail. The recurrence rate was 21%, in keeping with earlier studies. Factors influencing the risk of recurrence were the size of the keloid before treatment and complications occurring during or immediately after surgical excision. The data reported here suggest that surgical excision followed by brachytherapy is currently the best available method for treating keloids. (authors)