Médecine Nucléaire et Radiothérapie

Purpose: The work aims at studying forty Intensity-modulated radiation therapy (IMRT) plans designed using KonRad system and evaluating each of them under different conditions to study the effect of beams' orientations on the plan quality.
Methods: Clinical step-and-shoot IMRT treatment plans were designed for twenty patients, suffering from different types of non-CNS solid tumors, to be delivery on a Siemens Oncor accelerator with multi-leaf collimators MLCs (82 leaf). To ensure that the similarity or difference between the plans was due to effect of beams' orientations, the same optimization constraints were applied for each plan and all other parameters were kept constant.
Results: The analysis of performance was based on isodose distributions, Dose Volume Histograms (DVHs) for Planning Target Volume (PTV), the relevant Organs at Risk (OARs) as well as several physical indices like mean dose (Dmean), maximum dose (Dmax), 95% dose (D95), integral dose, volume of tumor receiving 2 Gy and 5 Gy, total number of segments and monitor units (MUs). Homogeneity index and conformation number were two other evaluation parameters that were considered in this study.
Conclusion: All coplanar CP and non-coplanar NC techniques result in clinically acceptable plans, with comparable target doses and dose to critical organs within prescribed dose constraints. For different organs at risk, the coplanar IMRT, the greatest advantage of non-coplanar IMRT was the marked reduction of general trend was that non-coplanar plans achieved the lowest values, while coplanar plans showed the highest. Significant differences (P<0.05) exist only between the homogeneity index HI (1.092 and 1.088) and Monitor Unit MU (357.79 and 341.80) of CP and NC plans respectively. Compared with the integral dose (p=0.007).

Introduction: Differentiating osteomyelitis (OM) from charcot joint is a vital necessity. Despite having almost similar presentation, both OM and charcot joint are managed vastly different. This study proposes the use of combined Sulphur Colloid and Besilosomab (Scintumun) scan to differentiate OM from Charcot Joint based on the understanding of their dissimilar pathophysiology.

Method: Image acquisitions of two patients using the 99mTc-Scintimun and 99mTc-Sulphur colloid were obtained accordingly at the affected sites.

Result: Both patients produced similar images on the combined Sulphur Colloid and Scintimun scans. There were increased activity on both Sulphur Colloid and Scintimun scans which suggested the exclusion of OM in both cases. Both patients were treated conservatively by the primary team.

Conclusion: The combined study of Scintimun and Sulphur Colloid imaging is a useful tool in assisting the primary team to exclude OM although a wider data sample is needed to further support this study.

Purpose: To compare the complications and survival rate after different treatment modalities of advanced laryngopharyngeal cancer.

Methods: Retrospective study included 619 advanced laryngopharyngeal carcinoma, treated with either primary total laryngectomy (PTL), or salvage (STL) after partial laryngectomy, radio, chemoradiotherapy. Complications and survival rate were documented.

Results: Five years disease free survival rate amounted 60.9% for PTL, 54.3% for STL after partial laryngectomy, 50% for STL after radiotherapy and 43.8% for STL after chemoradiotherapy. Histologically positive neck was highly significantly associated with worse prognosis, much more than recurrence within larynx.

Conclusion: PTL gives the best survival rate with low complications for advanced laryngopharyngeal squamous cell carcinoma. Complications and survival rate of STL significantly depend on previous treatment of laryngopharyngeal cancer.

Introduction: Fractionated stereotactic radiosurgery (fSRS) is an effective definitive treatment for optic nerve (ON) tumors. It is controversial whether treatment to the ON requires attention to the position of the eye as some consider the movement to be negligible. We investigated in four patients to establish whether there is clinically significant displacement of the ON as the globe moves and the effect this may have on target coverage in fSRS treatments. Method: Four patients receiving radiotherapy treatment to the skull and requiring cone beam computed tomography (CBCT) matching were asked to look in different directions as routine CBCT were obtained. An fSRS plan was created, treating the ON with the patient looking straight ahead. The displacement of the ON from straight was measured, with the patient looking fully left or right, the DVH of the optic nerve in the three locations was compared. Results: The data collected showed that there could be a significant difference in optic nerve position as the patient’s gaze changed. The DVH showed that the PTV coverage was affected as the patient moved their gaze either left or right by up to 9% (95%CI is from -15% to -3%, p=0.012). Conclusion: As a result of our study we recommend cooperative patients receive some training to ensure that optic nerve positioning is maintained throughout simulation and treatment.

Prostate cancer (PCa) is the most frequent tumor in men worldwide. PCa bone metastasis is mainly osteosclerotic, and is caused by a relative excess of osteoblast activity. A superscan on Tc-99m bone scintigraphy is described in multiple skeletal metastatic disease. Prostate-specific membrane antigen (PSMA) is a cell surface protein with high expression in prostate carcinoma cells. Ga-68 labelled PSMA imaging is used for staging and to evaluate the most appropriate therapy.

FDG PET/CT has been used to help characterize indeterminate pulmonary nodules, and to stage Non-Small Cell Lung Cancer (NSCLC) since January of 1998. The ever-expanding utilization of this modality in oncologic imaging cancer patients presented unique challenges for imagers who may not have received specialized training in the interpretation of PET/CT images. Interpretation of FDG PET/CT is particularly challenging in the thorax where inflammatory processes are common and often coexist with malignancy, rendering accurate tumor staging difficult. This article presents a systematic approach to FDG PET/CT interpretation in lung cancer staging, addressing common confounding situations often encountered. Although this illustrative discussion focuses on lung cancer staging, most of these tips could be applied to other types of cancer as well.

UV radiation has been established as a pro-oxidant that mediates tissue injury by triggering the generation of free radicals. However UVA induced oxidative injury has never been investigated before in the skin of a tropical diurnal rodent which spends longer time directly under the sun for foraging. The present study aimed to note the level of oxidative stress induced by 6.36 Jcm-2 UVA radiations on the skin and its possible prevention by melatonin. The oxidative load was assessed by the activities of key antioxidant enzymes (superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT)) and generation of thiobarbituric acid reactive substances (TBARS). Cutaneous apoptosis if any was checked by the expression of Bcl-2, p53 and Heme oxygenase-I (HO-I). Melatonin membrane receptor expression (MT1) and AANAT activity was also investigated to elucidate the protective effect of melatonin. UVA radiation increased the lipid peroxidation, suppressed the enzymatic antioxidant defense system and increased the HO-I expression. Melatonin restored redox balance and up regulated Bcl-2 and down regulated p53 levels. The restoration of AANAT activity also proved beneficial. In summary melatonin can be a part of topical applications or oral supplements that might help to reduce the UVA radiation mediated cutaneous oxidative damages.