The British journal of radiology
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Case Reports
Thoracic paravertebral block for analgesia following liver mass radiofrequency ablation.
A 66-year-old man presented for a second attempt of radiofrequency ablation of a metastatic carcinoid liver lesion. The first attempt using intravenous sedation was unsuccessful because of inadequate pain control and subsequent patient combativeness. ⋯ The patient's pain score remained 0 throughout the following day, and no further analgesics were required. Thoracic paravertebral block can provide complete and lasting analgesia following hepatic radiofrequency ablation, and warrants further study for patients undergoing hepatic radiological interventions.
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The purpose of this work was to determine alternative radiotherapy (RT) regimens that are biologically equivalent to clinically proven treatments using different RT modalities or different fractionation schemes. The concept of equivalent uniform dose (EUD) is used with the linear quadratic model to determine equivalent treatment regimens using two representative sets of parameters derived from clinical data: (i) alpha/beta = 3.1 Gy and alpha = 0.15 Gy(-1), and (ii) alpha/beta = 1.5 Gy and alpha = 0.04 Gy(-1). The EUD values for the critical structure (rectum) are also calculated. ⋯ For example, the alternative regimens, calculated with the alpha/beta ratio of 3.1 Gy, that would be biologically equivalent to external beam RT (EBRT) of 76 Gy (38x2.0 Gy) include: EBRT hypofractionation of 21x3.0 Gy; I-125 implant of 156 Gy; Pd-103 implant of 128 Gy; high dose rate (HDR) brachytherapy of 4x10.5 Gy; I-125 implant of 65 Gy combined with EBRT of 23x2.0 Gy; and HDR brachytherapy of 3x5.9 Gy combined with EBRT of 23x2.0 Gy. Similar data for other parameters are also presented. With caution, the data presented may be useful in designing clinical trials to explore new RT strategies, such as image-guided intensity-modulated RT.