Comparison of three high-resolution digitizers for radiochromic film dosimetry.

A recently introduced radiographic film scanner from Howtek is evaluated and compared to two other commercially available densitometry systems for its use in radiochromic (RC) film dosimetry in the clinical dose range 0-100 Gy. It has a high-intensity red LED light-source centered at 662 nm (near the major absorption peak for RC film), and is coupled to a CCD linear array detector. This new densitometry system is directly compared to two high-resolution film scanners commonly employed in RC film dosimetry, namely the Lumiscan 75 digitizer (He-Ne laser light source) and the Vidar VXR-16 digitizer (fluorescent light source).

The use of an inexpensive red acetate filter to improve the sensitivity of GAFChromic dosimetry.

The sensitivity of GAFChromic dosimetry using a conventional broad band light source densitometer has significantly been improved twofold using an inexpensive red acetate filter overlay during the densitometric measurements. This thin sheet of red acetate enhances the dosimetric analysis of radiochromic blue image distributions recorded on GAFChromic films. The combination provides higher sensitivity in the optical density measurements than the more expensive He-Ne laser-scanning densitometers.

A rapid colour stabilization technique for radiochromic film dosimetry.

Various forms of GAFChromic film have been used for several years as radiographic media for measuring dose distributions of brachytherapy sources and small radiation fields. Upon irradiation the film changes colour and darkens with time post-irradiation. The darkening is most rapid in the first 24 h, and it has been suggested that for accurate dosimetry a waiting period of 24 h should occur before any optical density (OD) measurements are taken.

The use of improved radiochromic film for in vivo quality assurance of high dose rate brachytherapy.

GAFChromic film has become increasingly popular for radiation dosimetry. In this study we explore the use of GAFChromic film as an in vivo dosimeter for quality assurance (QA) of fractionated high dose rate 192Ir treatments. Accuracy of dose distribution is explored for the simple vaginal cylinder geometry for which the dose can be easily calculated for comparison.

Predicting optical densitometer response as a function of light source characteristics for radiochromic film dosimetry.

Various forms of GAFChromic (GC) film have been used for several years as radiographic media for measuring dose distributions of brachytherapy sources and small radiation fields. In order to optimize the measurement sensitivity and thus improve precision, we describe a method to calculate the dose response curves (net optical density at a give wavelength or spectrum versus absorbed dose) for different densitometer light sources using measured GC film absorption spectra. Comparison with measurements on the latest version of GC film (model MD-55-2) using four types of densitometers [He-Ne laser, broadband (white light) densitometer, and two LED (red-light) filtered densitometers] confirm the accuracy of this predictive model.

The investigation of 32P wire for catheter-based endovascular irradiation.

The dose distribution from a 32P source has been measured and calculated in order to evaluate its application in endovascular irradiation. The source dimension was 27 mm in length and 0.3 mm in diameter and was embedded in the end of a Ni-Ti wire.

Comparison of dose response of radiochromic film measured with He-Ne laser, broadband, and filtered light densitometers.

Dose response curves for GAFChromic MD-55-2 film were measured using three different densitometer systems: a He-Ne laser densitometer, a broadband (white light) densitometer, and a filtered red light densitometer. These were found to differ significantly; the dose needed to achieve a net optical density of 1 (DNOD1) was greater than 100 Gy for the white light densitometer, 56 Gy for the He-Ne densitometer, and only 14.8 Gy for the filtered red light densitometer.

Changing the technique of background subtraction alters calculated renal function on pediatric mercaptoacetyltriglycine renography.

Purpose: Although many operative decisions are based on apparent changes in function detected by serial diuretic renography, the reliability of relative renal function data has been questioned. We investigated the effect of background subtraction on calculated renal function.

Materials And Methods: We reviewed 23 pediatric mercaptoacetyltriglycine renograms.

Exogenous endothelin-1 causes renal vasodilation in the fetal lamb.

Purpose: Endothelin-1 is known to be a potent vasoconstrictor. We investigated the effects and mechanisms of action of endothelin-1 and its receptors in regulating renal vascular tone in the fetal lamb.

Materials And Methods: We observed the in vivo effects of endothelin-1, an endothelin-b receptor agonist (4-alanine-endothelin-1), endothelin-a receptor antagonists (BQ-610 and BQ-123), and the inhibition of prostaglandin and nitric oxide synthesis on the response of the renal circulation to endothelin-1 in a chronic preparation in third trimester fetal lambs.

Contradictory renal function measured with mercaptoacetyltriglycine diuretic renography in unilateral hydronephrosis.

Purpose: We studied apparently supranormal renal function in hydronephrotic kidneys, as measured by 99mtechnetium mercaptoacetyltriglycine renography.

Materials And Methods: We retrospectively reviewed the clinical history, ultrasonography and renography of 29 children.

Results: Of the 29 children 7 had greater than 50% relative function in the hydronephrotic kidney.

Renal preservation despite 35 days of partial bladder obstruction in the fetal lamb.

To determine whether the increase in renal blood flow and preservation of renal function that we demonstrated after 10 days of chronic partial bladder obstruction in the third trimester fetal lamb also occur after earlier longer obstruction, we modified our preparation and studied the effects of 35 days of obstruction begun during the second trimester. Partial bladder obstruction was created in 10 fetal lambs at 90 days of gestation (term equals 147 days). At repeat surgical intervention 28 days later vascular catheters and a left renal artery flow transducer were placed, and catheters were externalized.

Newborn penile glans amputation during circumcision and successful reattachment.

Circumcision, the most common operation in male patients in the United States, is performed by a variety of health care professionals. Although not technically difficult, it results in a large number of reported and unreported complications annually. We report the successful reattachment of a distal penile glans, which was amputated when the Sheldon clamp was used for newborn circumcision.

Toxoplasmosis of the bladder: case report and review of the literature.

Toxoplasma gondii is an intracellular parasite that is responsible for an asymptomatic or minimally symptomatic lymphadenopathy syndrome, which in the immunocompromised host can be life threatening. Toxoplasmosis commonly affects the central nervous system. Genitourinary involvement is uncommon with reported cases limited to Toxoplasma orchitis and the nephrotic syndrome.

Munchausen's syndrome: manifestation as renal colic.

Over a four-year period, 3 patients with manifestations of renal colic were identified to have Munchausen's syndrome. A review of these cases and the literature is undertaken to provide urologists with a greater understanding of the origin and treatment of this syndrome.

Laparoscopic pyelocaliceal diverticula ablation.

Pyelocaliceal diverticula are cystic urine collections within the renal parenchyma communicating with the collecting system. They occur in 0.2% to 0.