Head CT examinations may result in significant and unnecessary exposure to the lens of the eye. The International Commission of Radiological Protection (ICRP) has estimated the threshold for detectable opacities in the lens from a single brief exposure to be 0.5 2Gy and the threshold for visual impairment (cataract) to be 5Gy. The lens dose for sequential CT scanning of the brain with the orbit...

PURPOSE This technical note quantifies the dose and image quality performance of a clinically available organ-dose-based tube current modulation (ODM) technique, using experimental and simulation phantom studies. The investigated ODM implementation reduces the tube current for the anterior source positions, without increasing current for posterior positions, although such an approach was also e...

PURPOSE To investigate lens growth after different doses of ultraviolet radiation (UVR) and to investigate the long-term effect of a near-threshold UVR dose on the refractive index distribution in the lens. METHODS Sprague-Dawley rats received UVR (lambda(MAX) = 300 nm) unilaterally during a 15-minute period. The exposure dose ranged from 0.1 to 20 kJ/m(2), and the rats were kept for up to 32...

Intravitreal triamcinolone is administered for a wide number of vitreoretinal conditions. Several complications including cataract formation, raised intraocular pressure, and endophthalmitis have been reported following intravitreal injections. We report a rare case wherein triamcinolone was inadvertently injected directly into the crystalline lens. A 41-year-old male presented to us with a his...

OBJECTIVES To examine the prevalence of radiation-associated lens opacities among interventional cardiologists and nurses and correlate with occupational radiation exposure. BACKGROUND Interventional cardiology personnel are exposed to relatively high levels of X-rays and based on recent findings of radiation-associated lens opacities in other cohorts, they may be at risk for cataract without...

The phase separation temperature (Tcat) was studied as a function of time (age) after the administration of a single dose of radiation (2000 rad), which induces cataract in the rabbit lens. In the normal unirradiated lens, Tcat decreases linearly with age at a rate (DTcat/dt) approximately 2.2 degrees/week. In the irradiated lens, Tcat initially decreases with age much less than the normal lens...

In the past the operational quantity H(p)(3) has been defined for calibration purposes in a slab phantom. Recently, an additional phantom in the form of a cylinder was suggested for eye lens dosimetry as a cylinder much better approximates the shape of a head than a slab. Therefore, this work investigates whether the quantity H(p)(3), when defined in the respective calibration phantom, adequate...

The phase separation temperature (Tcat) was studied as a function of time (age) after the administration of a single dose of radiation (2000 rad), which induces cataract in the rabbit lens. In the normal unirradiated lens, Tcat decreases linearly with age at a rate (dTcat/dt) ~ 2.2°/iveek. In the irradiated lens, Tcat initially decreases with age much less than the normal lens, then rises sharp...

The equivalent dose rate per positron fluence for the human eye lens is calculated using a Monte Carlo simulation code, EGS5, with two mathematical models (a computational head voxel phantom and a simple eye model). The eye lens doses for medical staff and carers as received from a radiopharmaceutical such as F-FDG, which is used in PET examinations, when spilled on the floor, and from positron...