Medicina Nuclear e Radioterapia

Purpose: To develop a framework for biologically-optimized routine intensity modulated radiotherapy (IMRT) treatment plans based on 18F-fluoro-deoxy-glucose (FDG)-Positron Emission Tomography (PET)/Computed Tomography imaging.

Methods and materials: The dose-planning FDG-PET images are first corrected for partial volume effect using an iterative algorithm with a noise suppression filter. Thereafter, the FDG-uptake is used for transforming the delineated clinical target volume (CTV) into a set of biological planning target volumes (bPTV). This is done with an optimization algorithm that groups pixel values with the objective of maximizing the FDG-uptake variance between bPTV. The resulting average FDG pixel intensity within each bPTV, together with a tumor control probability (TCP) function, are used to obtain the prescribed dose to each bPTV that maximize the total TCP, using dose limits to the organs at risk (OAR) as constraints. The accuracy of this method was tested on a phantom. Additionally, this framework was also tested on five patients with head-neck cancer, in a retrospective clinical trial.

Results: The extension of the obtained bPTV and their activity concentration showed good agreement with the true FDG distribution in the phantom. All patients planned using the presented methodology achieved a notable increase in TCP, compared to the standard IMRT plans.

Conclusions: FDG-PET together with this framework can be used to biologically optimize IMRT to individualize cancer treatment.

Background: To evaluate local control and cosmetic outcome in patients with cancer in the nasal cavity/vestibule treated with intensity-modulated radiotherapy (IMRT).

Methods: From 06/2008 – 11/2012 15 consecutive patients presenting nasal cavity (n=5), ala of the nose (n=5) or nasal vestibule tumors (n=5) were treated in our institution either postoperatively (n=8) or as definitive treatment (n=7).

Results: Mean/median follow-up (FU) was 30/22 months (range 17-62). Two patients suffered from a local relapse. As a salvage therapy an ablatio nasi was carried out in curative intention in both patients. Thereafter no failure was reported. Local control rate, ultimate local control and overall survival after 2 years were 87%, 100% and 100%, respectively. None of the patients developed grade II or higher late sequels. Cosmetic outcome after RT was very satisfying so far.

Conclusion: IMRT for nasal tumors is effective and well tolerated. Radical surgical procedures can be saved for curative salvage treatment.

Aims: The use of hypo fractionated irradiation of the whole breast has regained much interest after the publication of the results of large randomized trials showing equivalent results as using standard fractionation (START A and B, randomized START pilot trials, Canadian trial). Due to the relatively low numbers of patients treated with hypofractionation to the supraclavicular ±axillary (S/A) region, the question of the brachial plexus tolerance continues to be discussed. Aim of this work was to assess the high grade long term tolerance of the brachial plexus in our patients treated with 13x 3.3Gy to the S/A lymph nodes, in order to contribute to the question of plexus tolerance.
Materials and Methods: Between 1967 and 1977, 130 female breast cancer patients underwent postoperative hypo fractionated radiotherapy at the University Hospital Zurich. The most used schedule was 13x 3.3Gy midline dose, 3x/week (n=124) to the S/A region applied by equally rated antero-posterior/postero-anterior portals. A first assessment of the cohort was performed in 1994, which has been updated in December 2013. Patients with a follow up period <5 years or loco-regional disease have been excluded in 1994 (n=4, all without plexopathy). Pre-radiation surgery consisted of radical mastectomy in 98% and breast conserving operation in 2% of all patients, including axillary dissection. Pathological stage was pT1/2/3/4 in 28/58/10/4%; with pN0/pN+ in 57/43%. The mean/median follow up time of the cohort was 28.1/26.6 years (range, 7.2-44.8).
Results: One grade 2 brachial plexus neuropathy was observed.
Conclusion: The long term follow up in our patients corroborates the hypothesis of a total mid plane dose to the S/A region between 40-42Gy in 13 fractions being comparably safe as 25x 2.0Gy to 50Gy.

Abstract Objective: The influence of hyperglycaemia on the FDG uptake of regular adipose tissue at PET examinations was studied in clinical patients.

Methods: The report constitutes a sub-study of 500 consecutive clinical examinations evaluated in retrospect. The inclusion criteria comprised examinations with a normal, or a near normal FDG distribution. Patients who had been subjected to chemotherapy or radiotherapy <4 weeks prior to the examination were excluded. Otherwise, inclusion was made irrespective of concurrent diseases and/or therapy. In the current study, a sub-group of 62 patients with increased blood glucose levels (≥ 7.0 mmole/l) was compared with another 62 patients being paired with regard to age and gender and showing blood glucose levels within normal range (≤ 6.0 mmole/l). SUVmean of the axillary fat, perirenal fat, abdominal subcutis and gluteal fat were assessed. The gluteal fat was adequate for reliable evaluations. The other regions turned out more or less consistent for this because of the partial volume phenomenon, but were included because of the large number of observations, as well as no systematic influence on the outcome could be expected.

Results: There was a weak, but significantly higher FDG-uptake of all assessed adipose tissue depots in the patients showing increased blood glucose levels compared to the patients with normal blood glucose levels. The tracer uptake also varied between the different fat depots. This is in concordance with previous studies on insulinstimulated FDG-uptake showing differences of insulin resistance between various adipose tissue depots.

Conclusion: The uptake of FDG of adipose tissue is weakly increased in individuals with hyperglycemia compared to normal individuals. The differences are so small that they can be ignored in clinical practice.

Aims: This study aimed to evaluate the role of pretreatment 18F-Fluorodeoxyglucose positron emission tomography (18F-FDG-PET-CT) as a predictor of disease-free survival (DFS), and overall survival (OS) in locally advanced nasopharyngeal carcinoma (LANPC) patients treated definitively with docetaxel-based induction chemotherapy followed by concurrent chemoradiation (CRT). Materials and methods: This is a retrospective study approved by the institutional review board and included LANC patients treated definitively and consecutively between January 2008 and December 2012 with induction chemotherapy; docetaxel, cisplatin, and 5-flurouracil (TPF) followed by CRT utilizing weekly cisplatin. All patients had baseline pretreatment 18F-FDG-PET-CT. We studied the association between the baseline primary tumor maximum standardized uptake value (SUVmax) and the treatment outcomes; OS and DFS. Results: The study included 70 eligible LANPC patients. The 4-year OS and DFS rates were 86.7% and 78.6%, respectively. The median OS and DFS intervals were not reached. On a univariate analysis, the 4-years DFS was significantly higher in patients with pretreatment SUVmax <8 compared versus ≥ 8 (95% vs 57.7%, P=0.002). Furthermore, DFS was significantly correlated with pretreatment T stage (P=0.01), N stage (P=0.02), treatment response (P<0.001) and treatment breaks (P<0.001). On a multivariate analysis, the SUVmax category was the only factor correlated with 4-year DFS (Hazard ratio=10.2, 95% C I 1.3-116.8, P=0.035) but not OS (P=0.085). Disclosure statement: There is no actual or potential conflict of interest with the production and publication of this work. No author has a direct or indirect commercial financial incentive associated with the publication of this article. Conclusion: This study shows that the pretreatment primary tumor 18F-FDG-PET-CT SUVmax is a potential independent prognostic predictor of clinical outcomes in patients with LANC trea

Nuclear medicine imaging modalities have been reported to be useful in the diagnosis of parathyroid carcinoma (PC). However, false negative findings of bone metastasis from PC have been rarely reported. Here, we describe a patient undergoing nuclear medicine examinations since he had persistent high calcium and parathyroid hormone levels after resection of parathyroid tumor. 99mTc-Sestamibi (99mTc-MIBI) whole body scintigraphy (WBS) and 99mTc-methylene diphosphonate (99mTc-MDP) WBS were both negative. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18FDG-PET/CT) scan demonstrated osteolytic lesion in the fourth lumbar vertebrae (L4) on CT image with no obvious 18F-FDG accumulation on PET image. CT-guided fine needle aspiration and pathalogical examinations confirmed bone metastasis from PC.