Frank S. Harrington

Peripheral dose to the testes: the design and clinical use of a practical and effective gonadal shield☆

A simple and practical gonadal shield has been developed for use near megavoltage radiation fields. The lead shield encloses only the testes, allowing its use with nearly any radiation field that does not include the testes. The dose to the testes with and without the shield has been measured extensively both in phantoms and on patients. The gonadal shield allows a 3 to 10-fold reduction in dose to the testes depending primarily on the distance from the field edge to the gonads. When the shield is used, the gonadal dose is always less than 1% of the patients prescription dose. Based on our patient studies of testicular injury following conventionally-fractionated irradiation, a dose of less than 50 cGy (1% of a typical 5000 cGy treatment regimen) should preserve normal testicular function.

125I Interstitial brachytherapy for primary malignant brain tumors: Technical aspects of treatment planning and implantation methods

Use of interstitial radiation holds promise in the treatment of primary malignant brain tumors, but optimal technical factors have yet to be determined. We have developed a method of precise CT directed stereotactic placement of radioactive sources in a predetermined target volume. We use low activity (1-2 millicurie/speed) sources of 125I loaded in silastic catheters, which are positioned in a parallel array in the target. Positioning of such multiple sources toward the periphery of the volume enhances achievable dose homogeneity. Seeds of various activities can be differentially loaded into each catheter and the catheters can be positioned at various radii from the central target so that the treated volume corresponds to the identified (often irregular) target volume. Although the implant is designed to be permanent, the sources can be removed easily in a second procedure.

High-speed digitizer/averager data-acquisition system for fourier transform electron paramagnetic resonance spectroscopy

A high‐speed digitizer/averager data‐acquisition system designed and built as part of a 300‐MHz Fourier transform electron paramagnetic resonance spectrometer is described. There are two key features of the system: (1) the maximum digitizing rate is 300 Msamples/s and (2) a 256‐point free‐induction‐decay signal running summation can be updated in less than 3 μs. At the maximum digitizing rate, the system can sum 65 536 FIDs in 220 ms. The system consists of an analog‐to‐digital converter/adder unit (ADCA) and an IBM compatible personal computer. The ADCA is comprised of a digitizer, high‐speed sample buffers, high‐speed adders/memory, and control hardware. Design techniques, such as parallel processing, utilized to meet the high‐speed performance requirements are described. Trigger and timing signals for the system are derived from the spectrometer. System efficiency, synchronization, and time base stability are demonstrated in the spectrometer at a sampling frequency of 200 MHz. Signal‐to‐noise ratio enh...

A novel laparoscopic specimen entrapment device to facilitate morcellation of large renal tumors

A reusable laparoscopic instrument consisting of a flexible deployment ring and a barrel was fabricated, and an impermeable sac was sutured to the flexible ring before entrapment of the specimen and morcellation. The laparoscopic specimen entrapment device facilitated placement of large renal tumors within a sac for morcellation.

Television system for verification and documentation of treatment fields during intraoperative radiation therapy

Intraoperative radiation therapy (IORT) involves direct treatment of tumors or tumor beds with large single doses of radiation. The verification of the area to be treated before irradiation and the documentation of the treated area are critical for IORT, just as for other types of radiation therapy. A television system which allows the target area to be directly imaged immediately before irradiation has been developed. Verification and documentation of treatment fields has made the IORT television system indispensable.

Initial and residual toxicity following acute exposure of developing male rats to dibromochloropropane

Male Fischer 344 rats were given a single, sc injection of 1,2-dibromo-3-chloropropane (DBCP) at 6 or 25 days of age. One group of treated animals was killed 1 to 3 days afterward to compare the dose and time relationships of the acute toxic response of neonatal and weanling male rats to DBCP and another group at approximate sexual maturity (approximately 120 days of age) to detect residual toxic effects resulting from acute exposure. The 6-day-old rats were more susceptible than the 25-day-old rats to the acute toxic effects of DBCP, as characterized by reduced 48-hr survival, renal dysfunction, and renal and hepatic necrosis over the dose range of 80 to 320 mg/kg. The lowest dose tested, 20 mg/kg, and all higher doses reduced subsequent body and gonadal weight gains, and caused hypospermatogenesis or seminiferous tubular atrophy in animals exposed at 6 days of age and killed at sexual maturity. Similar effects were observed in animals exposed at 25 days of age, except that doses of 160 mg/kg or greater were required to produce residual toxic effects. These data indicate enhanced susceptibility of neonatal male rats to the gonadotoxic effects of dibromochloropropane, including the possibility of apparent irreversible injury caused by acute exposure.

An articulating retractor holder to facilitate laparoscopic adrenalectomy and nephrectomy.

PURPOSE Minimally invasive surgical approaches to renal and adrenal tumors have gained increasing use. The addition of robotic assistance and mechanical devices has decreased the number of assistants required for these often long cases. We describe an articulating arm retractor holder to aid in liver and spleen retraction during laparoscopic surgery. MATERIALS AND METHODS The articulating retractor holder consists of 4 components, including a base rod, flexible extension arm, stainless steel precision clamp and table attachment. During laparoscopy the abdomen is visualized using standard approaches. The articulating retractor holder is clamped to the table via the base rod and brought into the surgical field using sterile technique. A retractor is placed intracorporeally to elevate the liver or spleen and the handle is secured in place using the precision clamp. RESULTS The articulating retractor holder was used in all right and approximately 50% of left laparoscopic cases. Adequate visualization was obtained in all patients. There were no device failures or retractor related complications. CONCLUSIONS The articulating retractor holder is a useful tool to aid in laparoscopic retraction that should be added to the urologist armamentarium.

A graticule for evaluation of megavolt X-ray port films

Simulator films and port films are important documents of quality assurance of treatment delivery. Graticules have been constructed for linear accelerators which project mutually perpendicular arrays of equi-spaced dots on X ray films, similar to those projected by a graticule on the simulator. The spacing corresponds to 2 cm at the isocentric distance. The projected dot arrays function as built-in rulers in the films and greatly facilitate quantitative comparison of simulator films and treatment verification films, regardless of film magnification.

A Flexible Cystoscope Holder/Surgical Retractor that Really Works

Stabilization of equipment during endoscopic procedures frequently presents a problem. Most attempts to anchor a cystoscope have been cumbersome or have afforded transient stability. We describe an easily adjustable, flexible cystoscope holder that may be attached readily and locked in place after positioning. The unique open-sided clamp allows for a firm but delicate grasp of fiberoptic instruments. In addition to this function the flexible cystoscope holder may be adapted easily to become a surgical retractor. Our experience with this instrument has led to greater versatility during endoscopic and open procedures.

Interactions between Bromobenzene Dose, Glutathione Concentrations, and Organ Toxicities in Single- and Multiple-Treatment Studies

A single oral dose of 4.0 mmol/kg bromobenzene transiently depleted hepatic and renal reduced nonprotein sulfhydryl group (NPS) concentrations, caused hepatocellular necrosis, and increased serum glutamic-pyruvic transaminase activity in male Fischer 344 rats. The depletion of NPS had partially reversed by 24 hr, and NPS concentrations were approximately twice normal values by 48 hr post-treatment. When the effects of single and repeated (once daily for 2, 4, or 10 days) treatments with 4.0 mmol/kg were compared, it was apparent that the severity of hepatotoxicity lessened and the percentage depletions of hepatic and renal NPS concentrations decreased with increasing length of bromobenzene treatment. There were essentially no signs of toxicity following the tenth treatment with 4.0 mmol/kg. Single-treatment studies indicated the following dose-response: 2.0 mmol/kg bromobenzene depleted liver NPS and was hepatotoxic, 0.5 mmol/kg caused a lesser depletion of liver NPS and was not (overtly) hepatotoxic, and 0.0625 mmol/kg was the maximum dose that did not deplete liver NPS. The responses to single and multiple (ten) treatments with these representative doses were compared. Liver injury was observed after a single but not after the tenth daily treatment with 2.0 mmol/kg. Both the single and the tenth administrations of 2.0 mmol/kg depleted hepatic NPS, but the percentage of depletion was greater after the first than after the tenth dose. Liver injury was not detected with lower dose regimens. The patterns of NPS depletion in liver and kidney were similar after single or multiple (ten) treatments. The minimum NPS concentrations produced, however, were lower after single than after multiple treatments. The molar amounts of liver NPS depleted after the tenth treatment appeared to be equivalent to or greater than those after the first, but prior bromobenzene exposure resulted in a higher concentration of tissue NPS being present at the time of the final treatment. Thus, the minimum tissue concentrations of NPS were greater after multiple treatments than after single treatments, despite the loss of equivalent amounts of NPS. It is concluded from these studies that repeated treatment produces resistance to bromobenzene hepatotoxicity. This protective adaptation may be due to a chemically induced increase in liver glutathione concentration.