Ramesh C. Verma

Digital Watermarking of Medical Images for Mobile Devices

Mobile devices are widely available to both consumers and businesses at affordable prices. These devices have the computational power to achieve tasks that were infeasible a few years ago. In medical facilities, mobile devices provide the medium for remote diagnosis and information retrieval. However, there are strict privacy issues that must be met. We investigate digital watermarking and information hiding techniques on mobile devices for data authentication. Due to limited bandwidth and storage capability of mobile devices, we also consider the use of digital watermarks and information hiding to pass medical information and images with relatively low bandwidth and storage.

Quantitative differences between the thyroid uptake of 123I and 99mTc

Unlike 123I, sodium pertechnetate Tc99m is known to be trapped by the thyroid gland without being further processed. Whether this property alone explains the total difference between the early thyroid uptake of these two isotopes was studied in a group of goitrous patients. The absolute activities of 99mTc were measured by a conjugate-view counting method and those of 123I by a coincidence counting method. The uptake was continuously registered to give uptake curves which were analyzed according to a three-compartment model of the thyroid. Both isotopes are postulated to bind to some carriers and then to be transported into the thyroid gland before they are further metabolized. Although the differences observed between the two uptakes were somewhat model dependent, the application of compartmental analysis provides a more detailed description of the differences between the two uptakes which occur even before the organification step.

Patterns of gallium uptake in amebic liver abscesses

Imaging with Ga–67 and Tc–99m sulfur colloid was performed in ten patients with amebic liver abscesses. The most common imaging pattern appeared to be with the sharp identification of a “rim” sign on delayed Ga–67 imaging, from 48–72 hours.

Radionuclide venography and the role of radionuclides in the detection of venous disease.

Until recently, the true incidence of venous thrombosis in the general population was difficult to determine. However, with the availability of noninvasive screening techniques, such data are now being gathered. The incidence of calf vein thrombosis, as measured by the fibrinogen uptake test in inpatient (medical and surgical) population, ranges from 30% to 60%.’ In carefully examined autopsy specimens, the incidence of deep vein thrombosis in the leg varied from 26% to 86%.’-’ 2

Tumor uptake of 5-fluorouracil, methotrexate, and Adriamycin vs gallium

Since the imaging pattern of 67Ga-citrate is well known, it can be the benchmark for evaluation of potential tumor imaging agents. Tritium labeled 5-fluorouracil, Adriamycin, (doxorubicin/Adria) and Methotrexate/Lederle were compared at 2 h to 67Ga-citrate at 2 and 48 h by percent uptake per gram of various tissues and tumor in rats implanted with Walker 256 carcinosarcoma. 67Ga at 48 h showed approximately three times more uptake in the tumor than 5 fluorouracil and eight times more than the others. 5 Fluorouracil showed approximately three times greater uptake than Methotrexate or doxorubicin and 1.4 times the 2 h uptake of 67Ga. 5 Fluorouracil shows potential as an imaging agent especially where the waiting time between injection and imaging must be short.