9 Reporting in Brachytherapy: Dose and Volume Specification

180 Reporting in Brachytherapy

6.7 Recommendations for reporting interstitial therapy-Summary The following data are recommended by the ICRU (Report 58) (45) for reporting interstitial therapy. Reporting at level 2 (and 3) shall always include all data that should be reported at level 1. * Description of the clinical conditions, including GTV, CTV (sections 2.1 - 2.6, p. 158) (a) * Description of the technique (is the application performed following a “system” ?) (section 3, p. 163) (b)

* Source specification, including RAKR and TRAK (section 4, p. 165) (c) * Complete description of time-dose pattern (section 5, p. 168) (d) * Treatment prescription (section 1.1, p. 155) (e)

* Mean Central Dose (MCD), Minimum Target Dose, Homogeneity Index (sections 6.3.1, 6.3.2, 6.5) * Volumes and their dimensions, including PTV, Treated Volume (2), high-dose regions, low- dose regions, reference volume, irradiated volume (f) . * Organs at risk (section 2.6, p. 163) a) The clinical conditions should be described as completely as possible when reporting at level 1, completely at level 2. Reporting should include the description of the GTV and CTV. (b) The treatment technique should be described in detail. In particular, it should be clearly indicated whether -or not- a “system“ is followed for prescribing, recording and reporting. (c) A clear distinction should be made between specification of the sources and specification of the doses to the patient. The TRAK should (and can) always be reported at Level 1. (d) The time-dose pattern at any point depends on the technique, particularly when a moving source is used. Description of the technique and of the time-dose pattern should then be closely correlated. If biological “equivalence” is sought for comparison with treatments performed with other time-dose patterns, the radiobiological models and the “weighting factors” should be clearly indicated. In any case, reporting “weighted doses” should complement but not replace reporting of the (physical) absorbed doses and the actual time dose-pattern. (e) The prescribed dose, as specified here for interstitial therapy, is the dose that the radiation oncologist intends to give and which is entered in the patient´s chart. Depending on the system used, the approach for dose prescription in interstitial therapy may differ from centre to centre. If the prescribed dose is not the Minimum Target Dose nor the Mean Central Dose (MCD), the method for dose prescription should be reported. If, for clinical or technical reasons, the dose actually delivered differs from the prescribed dose, this should be reported. (f) Reporting dimensions of volumes is typically part of reporting at level 2. In addition to the Treated Volume, the dimensions of the high- or low-dose region(s), any dose uniformity data, and additional representation of dose distribution if available should be reported .