Publications (139) View all
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Article: Impact of PET/CT on planning of radiotherapy in head and neck cancer.
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ABSTRACT: Radiation therapy (RT) has a prominent role in the treatment of locally advanced head and neck cancer. Image and biologically guided intensity modulated RT are becoming strongholds of state-of-the-art management with positron emission tomography (PET)/computed tomography (CT) as the preferred diagnostic tool in treatment planning. The procedures required in the workflow from diagnosis to treatment plan are complex and consensus on optimal image acquisition, reconstruction parameters and contouring methods remains to be established. In spite of this the potential of PET/CT-based treatment planning has been widely recognized and many large referral centres have adopted the technique in either a routine or an experimental setting. PET/CT with 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) assists in selection of correct treatment goal and dose optimisation and increases the confidence of contouring process modifying treatment plan in most patients. For dose escalation and adaptive RT strategies PET may provide regional distribution of desired tumour characteristics such as hypoxic, metabolically active or rapidly proliferating sub-volumes. It is expected that within a few years PET/CT will be recommended for all patients presenting with stage III-IV disease considering the obvious benefits associated with more accurate volumetric presentation of primary and locoregional disease and the improved opportunities to conform and escalate RT dose in an attempt to improve therapeutic gain.The quarterly journal of nuclear medicine and molecular imaging: official publication of the Italian Association of Nuclear Medicine (AIMN) [and] the International Association of Radiopharmacology (IAR), [and] Section of the Society of... 10/2010; 54(5):521-32. -
Article: Clinical PET imaging of insulinoma and beta-cell hyperplasia.
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ABSTRACT: Persistent hyperinsulinemic hypoglycemia (PHH) is caused by solitary benign insulinoma or hyperplasia of pancreatic beta cells. In infants, PHH is caused by functionally defective hyperplastic beta cells, which are either diffusely or focally distributed in the pancreas. In adults, insulinoma is the most common cause of PHH, but recently, an increasing number of beta-cell hyperplasias has been reported among adults. The cause of adult beta-cell hyperplasia is not known. Whether the increased use of bariatric surgery in the treatment of severe obesity plays a role here is under investigation. Accurate localization of disease focus in both insulinoma and focal beta-cell hyperplasia provides an important support for surgery, especially as the use of laparoscopic surgery has increased. Conventional imaging of these challenging pancreatic lesions has evolved during recent years, but current imaging methods still lack sufficient sensitivity or are invasive. In most pancreatic NETs, the usefulness of positron emission tomography (PET) with fluorine-labeled fluorodeoxyglucose ([(18)F]FDG) for lesion detection is limited because of the low glucose turnover of these tumors. Based on the capacity of pancreatic beta cells to take up and decarboxylate amine precursors, several investigators have studied patients with pancreatic NETs using aminoacid precursors, such as [(18)F]dihydroxyphenylalanine (DOPA) and [(11)C]hydroxytryptophan (5-HTP), in an attempt to increase the sensitivity of PET scanning. Another characteristic of NETs is the expression of somatostatin receptors, and thus encouraging studies with somatostatin receptor imaging with [(18)Ga]-labeled somatostatin analogs have emerged as a new interesting imaging tool for the diagnosis of pancreatic NETs. This article provides an overview of our experiences and the current literature on PET imaging in patients with PHH caused by insulinoma or beta-cell hyperplasia.Current pharmaceutical design 01/2010; 16(14):1550-60. · 4.41 Impact Factor -
Article: Uncoupling of fatty acid and glucose metabolism in malignant lymphoma: a PET study
British Journal of Cancer 06/1999; · 5.04 Impact Factor -
Article: A dosimetric phantom study of dose accuracy and build-up effects using IMRT and RapidArc in stereotactic irradiation of lung tumours.
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ABSTRACT: Stereotactic lung radiotherapy (SLRT) has emerged as a curative treatment for medically inoperable patients with early-stage non-small cell lung cancer (NSCLC) and the use of intensity-modulated radiotherapy (IMRT) and volumetric modulated arc treatments (VMAT) have been proposed as the best practical approaches for the delivery of SLRT. However, a large number of narrow field shapes are needed in the dose delivery of intensity-modulated techniques and the probability of underdosing the tumour periphery increases as the effective field size is decreased. The purpose of this study was to evaluate small lung tumour doses irradiated by intensity-modulated techniques to understand the risk for dose calculation errors in precision radiotherapy such as SLRT. The study was executed with two heterogeneous phantoms with targets of Ø1.5 and Ø4.0 cm. Dose distributions in the simulated tumours delivered by small sliding window apertures (SWAs), IMRT and RapidArc treatment plans were measured with radiochromic film. Calculation algorithms of pencil beam convolution (PBC) and anisotropic analytic algorithm (AAA) were used to calculate the corresponding dose distributions. Peripheral doses of the tumours were decreased as SWA decreased, which was not modelled by the calculation algorithms. The smallest SWA studied was 2 mm, which reduced the 90% isodose line width by 4.2 mm with the Ø4.0 cm tumour as compared to open field irradiation. PBC was not able to predict the dose accurately as the gamma evaluation failed to meet the criteria of ±3%/±1 mm on average in 61% of the defined volume with the smaller tumour. With AAA the corresponding value was 16%. The dosimetric inaccuracy of AAA was within ±3% with the optimized treatment plans of IMRT and RapidArc. The exception was the clinical RapidArc plan with dose overestimation of 4%. Overall, the peripheral doses of the simulated lung tumours were decreased by decreasing the SWA. To achieve adequate surface dose coverage to small lung tumours with a difference less than 1 mm in the isodose line radius between the open and modulated field, a larger than 6 mm SWA should be used in the dose delivery of SLRT.Radiation Oncology 05/2012; 7:79. · 2.32 Impact Factor -
Article: Resistance, not tachyphylaxis or tolerance.
The British journal of ophthalmology 04/2012; 96(8):1153-4. · 2.92 Impact Factor
