Medicina Nuclear e Radioterapia

Purpose: Non-rigid image registration (NIR) is useful for adaptive radiotherapy. However, no method has been established for evaluating the quality of the algorithms used in NIR. To remedy this situation, we demonstrate herein a novel method to evaluate NIR algorithms. Methods: We define the NIR error as the discrepancy distance between (i) the organ contours obtained from computed tomography (CT) images acquired during the treatment period (reference contours) and (ii) the contours obtained from the treatment-planning CT images that are constructed by automated propagation during the treatment period (evaluation contours). However, the continuous positional relationship between the points where the reference contour intersects the evaluation contour is assumed to be maintained. In addition, we adapt the proposed method so that it can be applied to the contours of complex organs such as spherical and tubular organs. To demonstrate this method, we measure the contours of the prostate, right seminal vesicle, left seminal vesicle, urinary bladder, and rectum. The obtained NIR error presented in two-dimensional (2D) discrepancy maps. Results: The 2D discrepancy maps show the difference between the reference and evaluation contours from CT images. The proposed method measures the difference between the contours of spherical and tubular organs and evaluates the NIR error based on the positional relationship between the points constituting the contours. Conclusions: This study accounts for and measures the continuous positional relationship between corresponding points in the contours of complex-shaped spherical and tubular organs with irregularities and evaluates NIR algorithms based on these organ contours.

Objective: Lutetium-177 labelled PSMA-617 is an emerging radiopharmaceutical for targeted radionuclide therapy of prostate cancer (PCa) and hence there is an interest in the formulation and clinical application of this novel tracer. This paper summarises the studies undertaken to prepare clinical doses of [177Lu]PSMA-617 for therapy of prostate cancer patients. Experimental: [177Lu]PSMA-617 was prepared by reacting 177LuCl3 (5.4 GBq to 15.8 GBq, specific activity 650 MBq/μg to 860 MBq/μg) with 100 μg to 300 μg of PSMA-617 at pH 4.5-5. Radiochemical (RC) yields were estimated by thin layer and paper chromatography. When RC yields were lower than 95% the product was purified using a C18 cartridge which removed unreacted 177LuCl3. Two patients having histopathologically proven PCa and having significant levels of metastasis were given freshly prepared [177Lu]PSMA-617. Results: [177Lu]PSMA-617 could be prepared in high yields using CA low specific activity 177Lu and using modest amounts of ligand. Purification using a C18 cartridge provided the product with high RC purity. The product formed was stable for several days when stored at 4°C. SPECT images acquired post therapy showed that the [177Lu]PSMA-617 accumulated in most lesions identified by [68Ga]PSMA-11 PET-CT imaging. No redistribution of activity accumulated in lesions was seen in images acquired up to 7th day, post therapy. Therapy was well tolerated by the patients with no adverse reaction reported. Conclusion: The studies carried out suggest that therapeutic doses of [177Lu]PSMA-11 could be prepared by using low specific activity, carrier added 177Lu. Clinical studies demonstrated the uptake and retention of the tracer in prostate cancer lesions.

Danger signal was first proposed in 1994. In response to danger signal, dendritic cells, as the director of the T-cell immune system, would be matured and further enhance T-cell response. Hyaluronan had been reported as one of endogenous danger signals. Because of Seprafilm (most used for preventing post-operation adhesion) is also an hyaluronate-based agent, so we choose Seprafilm as our “candidate” of emerging danger signal to increasing T-cell response. We perform a pilot study in 10 ovarian cancer patients to compare the immune risk profiles between cases using Seprafilm (5 cases) and not using Seprafilm (5 cases). We found that there is no statistical difference on the immune risk profiles between two groups. However, a trend of increased CD4 in Seprafilm group was noted, indicating that Seprafilm might be an optional agent mimic danger signal. The potential value of Seprafilm to augment host immunosurveillance to improve survival rate in cancer patients is unknown, further study is needed to clarify the possibility of clinical applications.

Background: To evaluate radiotherapy dose escalation using volumetric modulated arc therapy (VMAT) and image guided radiotherapy (IGRT) with concurrent chemotherapy in locally advanced cervix cancer (LACC) and compare it with conventional radiation therapy (CRT) in terms of the toxicity and clinical outcomes. Methods and Materials: Data base was reviewed for all LACC patients treated either by conventional radiation therapy or dose escalation volumetric modulated arc therapy, with concurrent weekly Cisplatin 40 mg/m2 followed by high dose rate brachytherapy. The primary and secondary endpoints were toxicity, disease-free survival and overall survival respectively. Results: Of 60 patients, 40 patients received CRT and 20 received VMAT. The median follow-up time in the CRT arm was 47 months (11-89), and 35 months (13-47) in the VMAT arm. Hemoglobin toxicity (Grade I-II) was encountered in 97.5% and 90% (p=0.03) while (Grade I-III) Leukopenia was 90% and 70% (p=0.02), respectively. There was no grade 3 or 4 gastrointestinal or genitourinary (GI or GU) toxicity. At 36 months, disease-free survival was 45% in the CRT group versus 75% in the VMAT group (p=0.03), and overall survival was 65% in the CRT group versus 85% in the VMAT group (p=0.8). Conclusion: VMAT is associated with significantly less toxicity and comparable or even better clinical outcome compared with CRT. Further studies with larger sample sizes and longer follow-up times are warranted to justify its use in routine clinical practice.

Laser-induced eye injuries have been reported more and more often in the past years, yet the laser is not a modern invention. Based on stimulated emission, the wavelength, energy dose and pulse duration of the laser are the determining factors for its possible hazard potential. The eye, which is the most vulnerable body part for laser radiation, can be affected. As medical treatment is discussed controversial, a great demand has been put on developing laser protection gear. The present review summarizes the physical basics, clinical findings and therapeutic options of laser-induced eye injuries.

Aim: To compare [68Ga]Ga-PSMA-HBED-CC PET and (99m)Tc-DPD bone scintigraphy for the detection of bone metastases from prostate cancer. Methods: [68Ga]Ga-PSMA-HBED-CC PET/CT and (99m)Tc-DPD bone scintigraphy in 19 men with histopathological proven prostate cancer were compared to each other for the sensitivity/specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) for the detection of bone metastases. Results: According to the standard of reference lesion-based analysis of [68Ga]Ga-PSMA-HBED-CC PET and (99m)Tc-DPD bone scintigraphy reached a sensitivity of 45.6%/34%, specificity of 86.4%/81.4%, accuracy of 60.5%/ 51.2%, positive predictive value of 85.5%/76.1%, and negative predictive value of 47.7%/41.4%, respectively. Conclusion: [68Ga]Ga-PSMA-HBED-CC PET could detect significantly more bone metastases in prostate cancer than (99m)Tc-DPD bone scintigraphy.

Objective: The jaw-tracking technique has been developed to reduce the radiation beam transmission in the regions blocked by multileaf collimator (MLC). The aim of this study is the dosimetric evaluation of the jaw-tracking technique in Volumetric Modulated Arc Therapy (VMAT).

Material and Methods: 31 VMAT cases treated with the jaw-tracking technique were employed and re-planned with fixed jaw to analyze the dosimetric influences of the planning target volume (PTV) and organs at risk (OARs) volume. The treatment sites were liver, lung, and pancreas. All plans were optimized and calculated under jawtracking and fixed jaw conditions to cover the prescription dose to 95% of PTV (D95%) using the treatment planning system. The dosimetric verification of the treatment plans, the uniformity of the target dose distributions, the partial volume doses in OARs, and the low-dose volume were evaluated to verify the dosimetric impact of the jaw-tracking.

Results: The jaw-tracking technique appeared to be able to provide some clinical advantages compared to the fixed-jaw technique. The dose uniformities in targets were similar between in jaw-tracking technique and in fixed jaw. It appeared that the jaw-tracking technique could significantly reduce the partial volume dose of OARs, for the kidney (p=0.008) and duodenum (p=0.028) in liver cancer cases, for the esophagus (p=0.015) in the lung cancer cases, and for the normal liver (p=0.005) and kidney (p=0.005) in the pancreatic cancer cases. The low-dose volumes with the jaw tracking technique were calculated to be smaller than those with fixed jaw setup when the effective maximum field dimension were 1.5 cm larger than the equivalent spherical diameter of the PTVs.

Conclusions: The partial volume dose of OARs and the low-dose volume could be significantly reduced by application of the jaw-tracking technique without any adverse effect of the dosimetric parameter for targets in VMAT.

Background: Two novel HER2 aptamers were recently selected with great potential for the in vitro diagnosis of HER2-positive cancer. The goal of this study was to examine the in vivo diagnostic potential of these HER2 aptamers. Methods: Both HER2 aptamers were radiolabelled with 68Ga, injected in mice bearing a HER2-positive and HER2-negative tumour and evaluated by PET/MRI. Results: Ex vivo bio distribution analysis revealed high uptake in the blood, tissues and organs, except the brain. Interestingly, this high uptake was explained by the slow blood clearance due to non-specific aptamer binding to blood proteins. We observed accumulation of radioactivity in both tumours in time. Although higher uptake in the HER2-positive tumour compared to the HER2-negative tumour was observed, this was accompanied with more necrosis in the HER2-negative tumour, which was observed by 18FDG PET/CT. Conclusion: This work presents a first step towards the development of 68Ga-labelled aptamers for molecular cancer imaging.

We report the case of an isolated fracture of the posteromedial tubercle of the talar process caused by a posterior tackle in a football player, which is an unusual and misdiagnosed fracture leading to a nonunion causing a chronic ankle pain. To our knowledge, this is the first reported case demonstrating the major interest of SPECT/CT to diagnose an unusual nonunion of the posteromedial tubercle of the talus.

The application of hybrid devices that is fused technologies is getting more and more important in the field of imaging diagnostics. The greatest advantage of this method is the combined use of several modalities, which can provide data about the morphological, functional and possibly molecular changes in different diseases simultaneously. In this paper the potentials, advantages and applicabilities of SPECT/CT (single photon emission computer tomograph/computer tomograph) are summarized mainly in oncological diseases but in other diseases as well. Multimodality devices detecting functional and morphological abnormalities simultaneously increase the specificity and diagnostic accuracy of nuclear medicine methods and therefore the effectiveness of therapy too.

Purpose: Acute pancreatitis is a systemic disease, and is usually closely associated with organ failures. This study was to investigate the pattern of organ failure in the course of acute pancreatitis. Recent Findings: A total of 783 severe acute pancreatitis (SAP) and moderately severe acute pancreatitis (MSAP) patients who were sequentially treated in Department of Surgery, Ruijin Hospital from January 2001 to December 2008 were retrospectively analyzed. All the patients were divided according to their outcomes into two groups: deceased group and survival group. The relationship between the happening of organ failure and outcome of the patients were observed. Then peripheral blood level of endotoxin core antibody and TNF-α between SAP and MSAP groups were compared. Among the 783 patients, the numbers of MSAP patients and SAP patients were 573 and 210 respectively. Overall, 698 patients were survived, which represents 89.1% of the total patients. Furthermore, 273 patients or 34.9% of the total were diagnosed with organ failure. There were 109 patients with single organ failure, 2 of which died; 81 and 60 patients with 2 organs failure and 3 organs failure respectively. In each group 30 patients died. Finally there were 23 patients with 4 or more organs failure and none of them survived. The rate is 15.3% (107/698) of the patients with single organ failure in survival group, while the corresponding number is only 2.4% (2/85) in deceased group. On the contrary, only 11.6% (81/698) patients in the survival group had multiple organ failure, while the number is 97.6% (83/85) in the deceased group. Respiratory, renal, cardiovascular, neurological, hematologic and hepatic failure occurred in 206, 80, 103, 92, 41, and 27 patients, with the incidence of 26.3%, 10.2%, 13.2%, 11.7%, 5.2%, and 3.4%; and the mortality rates were 38.8%, 63.8%, 49.5%, 37.0%, 53.7%, and 44.4% respectively. Peripheral blood levels of TNF-α and endotoxin core antibody in patients with SAP were significantly different with that of MSAP. Summary: In the course of acute pancreatitis, respiratory and cardiovascular failure has the highest incidence, and renal, hematologic failure is associated with poorest prognosis.