Feasibility study on the use of CMOS sensors as detectors in radioguided surgery with ß-- emitters.

Radioguided surgery (RGS) is a medical practice which thanks to a radiopharmaceutical tracer and a probe allows the surgeon to identify tumor residuals up to a millimetric resolution in real-time. The employment of ß- emitters, instead of γ or ß+, reduces background from healthy tissues, administered activity to the patient, and medical exposure. In a previous work the possibility of using a CMOS Imager (Aptina MT9V011), initially designed for visible light imaging, to detect ß- from 90Y or 90Sr sources has been established. Because of its possible application as counting probe in RGS, the performances of MT9V011 in clinical-like conditions were studied.1 Through horizontal scans on a collimated 90Sr source of different sizes (1, 3, 5, 7 mm), we have determined relationships between scan fit parameters and the source dimension, namely A quadratic correlation and a linear dependency of, respectively, signal integrated over scan interval, and maximum signal against source diameter, are determined. Horizontal scan measurements on a source, interposing collimators of different size, aim to determine relationships or correlations between scan fit parameters and source dimension. A quadratic correlation and a linear dependency of, respectively, signal integrated over scan interval, and maximum signal against source diameter are determined. In order to get closer to clinical conditions, agar-agar phantoms containing 90Y with different dimensions and activities were prepared. A 90Y phantom is characterized by a central spot and a ring all around, for simulating both signal (tumor) and background (surrounding healthy tissue). The relationship found between scan maximum and 90Sr source diameter is then exploited to extract the concentration ratio between spot and external ring of the 90Y phantom. This observable, defined as the ratio between the tumor and the nearby healthy tissues uptake simulates the Tumor-to-Non-tumor Ratio (TNR). With the aim of evaluating the sensor's ability to discriminate signal from background relying on the significance parameter, a further 90Y phantom, featuring a well-known and clinical-like activity will mimic the signal only condition. This result is used to extrapolate to different source sizes, after having estimated the background for various TNR. The obtained significance values suggest that the MT9V011 sensor is capable of distinguishing a signal from an estimated background, depending on the interplay among TNR, acquisition time and tumor diameter.

Personnel real time dosimetry in interventional radiology.

Interventional radiology and hemodynamic procedures have rapidly grown in number in the past decade, increasing the importance of personnel dosimetry not only for patients but also for medical staff. The optimization of the absorbed dose during operations is one of the goals that fostered the development of real-time dosimetric systems. Indeed, introducing proper procedure optimization, like correlating dose rate measurements with medical staff position inside the operating room, the absorbed dose could be reduced. Real-time dose measurements would greatly facilitate this task through real-time monitoring and automatic data recording. Besides real-time dose monitoring could allow automatic data recording. In this work, we will describe the calibration and validation of a wireless real-time prototype dosimeter based on a new sensor device (CMOS imager). The validation measurement campaign in clinical conditions has demonstrated the prototype capability of measuring dose-rates with a frequency in the range of few Hz, and an uncertainty smaller than 10%.

The accelerated polyvinyl-alcohol method for GSR collection--PVAL 2.0.

The polyvinyl-alcohol collection method (PVAL) is used in forensic practice to gather topographical information about gunshot residues (GSR) from the hands to decide if the subject has made use of firearms. The results allow a distinction between suicide and homicide. The only inconvenience of PVAL was that the procedure took about 60 min because three layers of liquid PVAL had to be applied and dried. Therefore, the collection method was only applied to corpses. The improved and accelerated PVAL 2.0 uses a sandwich technique. Cotton gauze for stabilization is moistened with a 10% PVAL solution. A solid film of PVAL (Solublon) is spread on the cotton mesh. The gauze is then modeled to the hand and dried with a hair dryer. After removing the cotton gauze, the traces are embedded in the water-soluble PVAL. The procedure does not take more than 15 min. The results demonstrate the qualities and advantages of PVAL: topographical distribution of GSR, highest gain of GSR, sampling of all other traces like blood, backspatter etc., and humidity does not reduce the gain. In addition, with the new PVAL 2.0 dislocation of GSR or contamination are excluded. PVAL 2.0 can also be applied on live suspects.

Traces of ricocheted action safety bullets.

Experimental gunshots were made with Action-1 and -3 ammunition (9 mm Luger) using a part dummy made of textile, pig skin, and gelatine as the target. After ricocheting off a concrete floor tile with impact angles of 15 degrees or 20 degrees, the deformed projectiles penetrated the gelatine block to a depth of between 21 and 37 cm. The ricochet angles varied between 5 degrees and 11 degrees. None of the bullets mushroomed after ricochet; a few bullets even overpenetrated. The ricocheted projectiles sprayed a substantial amount of copper particles onto the textile, and metallic fragments were also deposited along the bullet path. These traces were detected by high-resolution radiography. The Action-3 brass bullet was more resistant, had more kinetic energy, and was less deformed than the Action-1 copper bullet. The morphology of the wounds presented a very varied spectrum; round lesions were also observed. The results of the experimental study prove that ricocheted Action bullets present a serious risk of injury.

The MEN frangible: study of a new bullet in gelatin. Metallwerk Elisenhütte Nassau.

Experimental gunshots were made with 9 x 19 mm (9-mm Luger) Frangible ammunition using skin, gelatin, and bones as targets. Direct gunshots penetrated 50 cm into gelatin blocks without mushrooming or fragmentation. Skull bone was easily perforated. Head models were penetrated by the bullets, which broke down to myriad fragments within or outside the head. Gunshots through windshields and steel plates led to dangerous bullet fragmentation with a high risk of injury. Gunshots perforating tibias produced comminuted fractures. In all soft tissues, except the direct gunshots into gelatin, high-resolution radiography revealed many metallic fragments along the bullet path. Clinical radiography can show the larger copper fragments, but the explosion-like distribution of metallic foreign bodies in soft tissue is a serious surgical problem.

Radiological findings in gunshot wounds caused by hunting ammunition. An experimental study.

Experimental gunshots were made with hunting ammunition using a dummy model made of skin and foam rubber as the target. After penetration of intermediate targets of wood by the bullets, the characteristics of the wounds changed and their dimensions increased. The morphology of the wounds presented a very varied spectrum. When the gunshots had initially passed through wood 50 mm thick, radiographs of the skin showed a quantity of metallic residues between 10 microns and 1 mm. The metallic particles were wiped off the surface of the projectile by the target itself, whereby the best "wipe-off effect" was achieved with skin. The experimental findings suggest that the formation of the fine metallic residues is analogous to the development of the bullet wipe formed by lead bullets. Larger fragments flew into the target independently of the bullet and depending on the distance between the intermediate and final targets. A case example is documented.

[How dangerous are "mouse trap projectile traps"?]. / Wie gefährlich sind "Wühlmausschussfallen"?

The authors research by experiments to define the potency of wounding of a special mouse trap which belongs to the spring-guns. Besides the regular assigned 9 mm blank cartridge also the 9 x 17 mm "green" cattle stunning cartridge is tested. Shots were made on soap, cotton and skin on different conditions. As result the authors found that by close range shots (up to 1 cm) by the blank cartridge badly healing wounds are caused. The 600 Joule cattle stunning cartridge is able to mutilate the hand by contact shots.