A simple and accurate dosimetry protocol to estimate activity for hyperthyroidism treatment

BACKGROUND: Aim of the study was to evaluate accuracy of different dosimetry protocols in estimating the required 131I activity to treat hyperthyroid patients. MATERIALS AND METHODS: Forty consecutive patients were analysed: twenty-eight Graves’ disease; twelve autonomous thyroid nodule (ATN). Maximum-uptake, effective half-time and residence-time were estimated from Radioiodine Uptake Test. Residence-time was estimated using a bi-compartmental model. For 131I activity calculation, algorithms laid down in European Association of Nuclear Medicine (EANM) guidelines, ICRP 53 approach and a mono-exponential formula (ME), were compared with OLINDA/EXM results. RESULTS: Based on EANM guidelines, activities to be administered were 3% higher in Graves’ disease (p = 0.001) and 3% higher in ATN (p = 0.046). Calculated activities using ICRP 53 approach were significantly lower compared to OLINDA/EXM: 33% in Graves’ disease; 17% in ATN. Activities recommended by ME, were significantly higher: in Graves’ disease 20%; 42% in ATN. CONCLUSIONS: Only EANM algorithm predict quite well, compared to OLINDA/EXM, the required activity to treat hyperthyroid patients

a simple and accurate dosimetry protocol to estimate activity for hyperthyroidism treatment

BACKGROUND: Aim of the study was to evaluate accuracy of different dosimetry protocols in estimating the required 131I activity to treat hyperthyroid patients. MATERIALS AND METHODS: Forty consecutive patients were analysed: twenty-eight Graves' disease; twelve autonomous thyroid nodule (ATN). Maximum-uptake, effective half-time and residence-time were estimated from Radioiodine Uptake Test. Residence-time was estimated using a bi-compartmental model. For 131I activity calculation, algorithms laid down in European Association of Nuclear Medicine (EANM) guidelines, ICRP 53 approach and a mono-exponential formula (ME), were compared with OLINDA/EXM results. RESULTS: Based on EANM guidelines, activities to be administered were 3% higher in Graves' disease (p = 0.001) and 3% higher in ATN (p = 0.046). Calculated activities using ICRP 53 approach were significantly lower compared to OLINDA/EXM: 33% in Graves' disease; 17% in ATN. Activities recommended by ME, were significantly higher: in Graves' disease 20%; 42% in ATN. CONCLUSIONS: Only EANM algorithm predict quite well, compared to OLINDA/EXM, the required activity to treat hyperthyroid patients

Implementation of a program for quality assurance on leaf positioning accuracy using Gafchromic ® RTQA2 films

In radiotherapy treatments the correct dose delivery to the target volume and the consequent conservation of healthy tissues is affected by multileaf collimator (MLC) leaf positioning accuracy and reproducibility, mostly in intensity-modulated radiation therapy (IMRT): For this reason a quality assurance (QA) program is necessary to ensure the best treatment possible to each patient. The aim of this study is the implementation of a method using Gafchromic ® RTQA 2 films to perform routine QA on the MLC, both for qualitative and quantitative analysis. A flatbed document scanner (Epson 10000XL) was used in conjunction with radiochromic detector; a scanning protocol was firstly defined to improve readout accuracy. RTQA2 films were irradiated with 6 MV X-rays at different dose levels to obtain calibration curve. To evaluate the leaf positioning accuracy in different conditions, a rhomboidal shape and a field consisting in three rectangular segments were selected. The images quantitative analysis was handled with a program developed in MATLAB to evaluate the differences between expected and measured leaves positions. The reproducibility and global uncertainty of the method were estimated to be equal to 0.5% and 0.6 mm, respectively. Moreover, a qualitative test was performed: A garden picket fence field, consisting in multiple segments 2 × 22 cm 2 , was realized setting known leaves shifts to test the method sensitivity. The picket fence test shows that the method is able to detect displacements equal to 1 mm. The results suggest that Gafchromic ® RTQA2 films represent a reliable tool to perform MLC routine QA

A simple and accurate dosimetry protocol to estimate activity for hyperthyroidism treatment

BACKGROUND: Aim of the study was to evaluate accuracy of different dosimetry protocols in estimating the required 131I activity to treat hyperthyroid patients. MATERIALS AND METHODS: Forty consecutive patients were analysed: twenty-eight Graves' disease; twelve autonomous thyroid nodule (ATN). Maximum-uptake, effective half-time and residence-time were estimated from Radioiodine Uptake Test. Residence-time was estimated using a bi-compartmental model. For 131I activity calculation, algorithms laid down in European Association of Nuclear Medicine (EANM) guidelines, ICRP 53 approach and a mono-exponential formula (ME), were compared with OLINDA/EXM results. RESULTS: Based on EANM guidelines, activities to be administered were 3% higher in Graves' disease (p = 0.001) and 3% higher in ATN (p = 0.046). Calculated activities using ICRP 53 approach were significantly lower compared to OLINDA/EXM: 33% in Graves' disease; 17% in ATN. Activities recommended by ME, were significantly higher: in Graves' disease 20%; 42% in ATN. CONCLUSIONS: Only EANM algorithm predict quite well, compared to OLINDA/EXM, the required activity to treat hyperthyroid patients

A case of primary mediastinal Ewing′s sarcoma /primitive neuroectodermal tumor presenting with initial compression of superior vena cava

Ewing′s sarcomas and peripheral primitive neuroectodermal tumors (ES/PNETs) are high grade malignant neoplasms. These malignancies are characterized by a chromosome 22 rearrangement, arise from bone or soft tissue, predominantly affect children and young adults, and are grouped in the Ewing family of tumors. Multimodality treatment programs are the treatment of choice. Primary localization of ES/PNET in the mediastinum is extremely rare. We describe a case of ES/PNET presenting as a mediastinal mass with tracheal compression and initial signs of superior vena cava in a 66-year-old woman

CITK Loss Inhibits Growth of Group 3 and Group 4 Medulloblastoma Cells and Sensitizes Them to DNA-Damaging Agents

Medulloblastoma (MB) is the most common malignant brain tumor in children, and it is classified into four biological subgroups: WNT, Sonic Hedgehog (SHH), Group 3 and Group 4. The current treatment is surgery, followed by irradiation and chemotherapy. Unfortunately, these therapies are only partially effective. Citron kinase protein (CITK) has been proposed as a promising target for SHH MB, whose inactivation leads to DNA damage and apoptosis. D283 and D341 cell lines (Group 3/Group 4 MB) were silenced with established siRNA sequences against CITK, to assess the direct effects of its loss. Next, D283, D341, ONS-76 and DAOY cells were treated with ionizing radiation (IR) or cisplatin in combination with CITK knockdown. CITK depletion impaired proliferation and induced cytokinesis failure and apoptosis of G3/G4 MB cell lines. Furthermore, CITK knockdown produced an accumulation of DNA damage, with reduced RAD51 nuclear levels. Association of IR or cisplatin with CITK depletion strongly impaired the growth potential of all tested MB cells. These results indicate that CITK inactivation could prevent the expansion of G3/G4 MB and increase their sensitivity to DNA-damaging agents, by impairing homologous recombination. We suggest that CITK inhibition could be broadly associated with IR and adjuvant therapy in MB treatment