A Phase I Prospective Clinical Trial Using Volumetric Magnetic Resonance-Guided High Intensity Focused Ultrasound (MR-HIFU) Hyperthermia (HT) Combined with Radiotherapy and Chemotherapy for Recurrent Rectal Cancer

Abstract

Results: Among the 501 patients with a median follow-up of 58 months that received CRT, there were 26 (5.2%) events of late SB toxicity ! grade 2, and 21 (4.2%) events ! grade 3. Univariate analysis identified SB volumes exposed to 30 Gy as being significantly associated with grade !3 toxicity (p Z 0.019), while volumes of 25 Gy and 30 Gy were most predictive of grade ! 2 toxicity (p Z 0.023, 0.003). Logistic regression analysis identified volumes of 458 cc receiving 5 Gy (p Z 0.007), 330 cc for 15 Gy (p Z 0.02), 274 cc for 25 Gy (p Z 0.02), and 190 cc for 30 Gy (p Z 0.02) as predictive for grade !2 SB toxicity. Conclusion: This study reports on the late SB toxicity associated with CRT in a large cohort of rectal cancer patients. Dosimetric analysis identified SB volumes that are significantly associated with late SB toxicity of ! grade 2. When planning CRT for rectal cancer patients, restricting V30 to <190cc will be a useful guideline to keep grade !2 late SB toxicity to <5%.

Methods for MRI-guided treatment of painful bone metastases with Focused Ultrasound

“…This effect has been exploited for local tumor control, through thermal ablation [9]. A variety of therapeutic applications of HIFU are being investigated and/or are clinically available [10][11][12][13][14][15], most of them based on local tissue destruction by thermal ablation.…”

“…where E S is the energy delivered on the bone surface in joules per sonication that hits this surface, and S A ROT is the surface area on the bone within the region of treatment [15]. Both the energy and the bone surface are subject of definition choices.…”

“…Both the energy and the bone surface are subject of definition choices. In their paper [15], the authors did not describe in detail the way the delivered energy was calculated. The region of treatment and a set of contours defining the bone surface were manually drawn on pretreatment MR images in the planning HIFU software [1].…”

“…In a recent study, Bitton et al suggested the use of an estimate of the amount of ultrasound energy delivered to the target as an indicator [15]. They showed that the energy density on the bone surface (EDBS) showed correlation with pain relief in patients, making it a possible suitable candidate for prediction of the therapy outcome.…”

“…They showed that the energy density on the bone surface (EDBS) showed correlation with pain relief in patients, making it a possible suitable candidate for prediction of the therapy outcome. In that study, EDBS was calculated as the total acoustic energy that reaches the bone during the treatment procedure divided by the targeted surface area on the bone [15]. It was not explained which assumptions, model and conditions were used to calculate EDBS values.…”