28 Primary and secondary liver malignancies

Primary and secondary liver malignancies

11

THE GEC ESTROHANDBOOKOF BRACHYTHERAPY | Part II Clinical Practice Version 1 - 15/07/2022

Figure 6: The excess end of the brachytherapy catheter to the angiography sheath outside the patient can be measured with a sterile ruler as a second validation and can be used to validate the internal excess of the brachytherapy catheter.

Figure 7: Examplar cases with dose optimized to 1 × 20 Gy (green isoline). The puncture tract is treated with ~5 Gy to the catheter surface (see right image). Left image: Oligometastasis (breast cancer), prescription dose 1×20 Gy. Blue isoline: 15 Gy, green isoline: 20 Gy, yellow isoline: 30 Gy, white isoline: 60 Gy, GTV volume: 10.5 cm 3 , D100%: 20.1 Gy, D98%: 23.5 Gy, D95%: 25.8Gy, D90%: 29.7 Gy; Dmean: 59.7 Gy, OAR: Healthy liver volume: 1088 cm 3 , V5Gy: 22%, V10Gy: 9%. Right image: Oligometastasis (duodenal carcinoma), prescription dose 1×20 Gy. Dark blue isoline: 10 Gy, blue isoline: 15 Gy, green isoline: 20 Gy, yellow isoline: 30 Gy, red isoline: 40 Gy, white isoline: 60 Gy, GTV volume: 540 cm 3 , D100%: 18 Gy, D98%: 20Gy, D95%: 21.4 Gy, D90%: 23 Gy; Dmean: 42.8 Gy, OAR: Heart D0.1 cm 3 : 17.6 Gy, D1.0cm 3 : 16.5 Gy, Stomach D0.1 cm 3 : 11.2 Gy, D1.0 cm 3 : 9.9 Gy; Healthy liver volume: 1981 cm 3 , V5Gy: 65%, V10Gy: 32%.

11. MONITORING

image set and the deviations quantified. Tracking devices (e.g. electromagnetic tracking) allow for the validation of the correct source positions during dose delivery [60]. For each different brachytherapy technique, possible emergency scenarios must be considered. An advantage of the Seldinger technique is that with a catheter-in-catheter technique, the emergency procedure is easy to handle, even in the very rare case of a detached source (broken weld seam between source and Bowden drive cable) inside any catheter. In this case, the (source containing) brachytherapy catheters can be quickly removed from the angiography sheaths. Immediate measures must be taken to prevent bleeding after catheter removal. Catheter removal Since both, hepatic metastases and liver parenchyma are typically well perfused, complications may arise from bleeding along the

Treatment delivery After approval of the treatment plan and transfer to the afterloader software, the brachytherapy catheters are connected to the afterloader via transfer tubes and the dose is delivered to the target (see Figure 8). Verification of the correct catheter localization before initiating the dose delivery is essential. To do so, an additional low dose CT or equivalent imaging modality of the treatment region including all catheters immediately prior to the plan application should be considered, in order to ensure that no significant changes in catheter position and patient anatomy occurred between planning CT / MR and starting the dose delivery. For this purpose, imaging must be possible without moving the patient, since this could again lead to unexpected changes of anatomy or even catheter displacements.The freshly acquired CT / MR can then be registered to the planning