In breast cancer, the survival rate is related to the size of the lesion. Since the spatial resolution of whole-body (WB)-PET is limited, it is difficult to evaluate small cancerous lesions. To improve resolution, high-resolution dedicated breast PET (db-PET) scanners have been developed. However, the potential of db-PET has not yet been established, and there has been no report of the application of db-PET on an Oncovision device (MAMMI) in breast cancer cases in Japan.
The purpose of this study was to evaluate the potential of db-PET for assessing breast cancer. The influence of image reconstruction parameters was verified in a phantom evaluation, while we quantitatively investigated the ability of dB-PET to detect tumors, in comparison with WB-PET, with patients in the prone position, in a clinical evaluation. Despite a limited field of view in the vicinity of the chest wall, we show that db-PET has markedly better clinical value for diagnosing breast cancer as compared to WB-PET.
To prepare a weakly acidic cation-exchange fiber capable of binding lysozyme dissolved in a high-concentration phosphate buffer, acrylic acid (AA) was graft-polymerized onto a nylon-6 fiber by radiation-induced graft polymerization. The dynamic binding capacity (DBC) of the bed charged with the AA-grafted fiber at a space velocity of 20 h−1 was determined in a flow-through mode for lysozyme solutions buffered with 50–250 mM phosphate solution (pH 6.0). The DBC of the CM-Sepharose-FF-bead-packed column decreased from 88 to 9 mg/mL-bed with increasing buffer concentration. In contrast the AA-grafted-fiber-packed column exhibited a constant value of 200 mg/mL-bed independent of the buffer concentration from 50 to 200 mM.
An apparatus for on-site measurement of radiocaesium in pond sediment was developed by assembling commercially available parts. It gives vertical radiocaesium distribution in sediment from γ-ray count data measured by an array of PIN photodiode sensors. Successful conversion from γ-ray count rates to radiocaesium concentration in Bq/kg-wet was attained by an inversion code based on the maximum-entropy method. On-site tests at three ponds in Fukushima prefecture revealed that the apparatus gives vertical distributions close to those of core sampling method by 10 min measurement. It works about 5 h by a small mobile battery. The total cost for the apparatus is about 100,000 Japanese Yen which may not be unacceptable to individuals. The present method measures vertical distribution directly and is superior to other methods which assume empirical profile such as exponential distribution. Experimental error and application to other target such as soil or containers were also discussed.
The Subcommittee of Japan Radioisotope Association on Survey of Nuclear Medicine Practice in Japan has performed a nationwide questionnaire survey every five years since 1982. The latest questionnaire survey was performed in June 2017, resulting in more than 90％ response. The estimated total number of examinations using single photon emitters decreased by 5.7％ whereas the number of PET examinations increased by 24.5％ as compared to the survey in 2012. As a result, the total nuclear examinations increased by 4.1％. Due to the approval of 223Ra chloride and increase of thyroid cancer treatment, the total number of unsealed radionuclide therapy increased by 34.1％. These findings indicate that demands to nuclear medicine practice has been changing.