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Biomedical subjects

Jesse Aronowitz

Publications and source records attributed to Jesse Aronowitz.

5 recordsLinked to original sources
PubMed2006

The effect of radiation therapy on normal tissue function.

As more patients are treated for their primary malignancy with cure or increased disease-free intervals, injury to normal tissues will become more detectable and an important endpoint for study. Future protocols will probably be modified based on toxicity endpoints. In Hodgkin's disease, current protocols use response-based treatment strategies to limit therapy. The objective is to provide the same level of tumor control and follow normal tissue endpoints for outcome analysis. DVH analysis has improved the ability to analyze endpoint data for normal tissues. These image-guided platforms will provide the infrastructure needed to continue efforts in improving the delivery of radiation therapy.

Dose-Response Relationship, Radiation↗
PubMed2005

Variability of prostate brachytherapy pre-implant dosimetry: a multi-institutional analysis.

PURPOSE: To conduct a multi-institutional comparison of prostate brachytherapy pre-implant dosimetry of Pd-103 and I-125. METHODS AND MATERIALS: Eight experienced brachytherapists submitted Pd-103 and I-125 monotherapeutic and boost pre-implant dosimetry plans for central review. All 32 plans were calculated using the same transrectal ultrasound volumetric study. Seeds of any strength were acceptable, but were restricted to Theraseed Model 200 (Theragenics Inc., Buford, GA) and Oncura Oncoseed Model 6711 (Oncura, Plymouth Meeting, PA). The dosimetric analysis included evaluation of target volume, target to prostate ratio, target length, number of needles, seed activity, number of seeds, total activity, total activity divided by treatment planning volume, the use of extracapsular seeds, and average treatment margins (defined as the perpendicular distance between the prostate capsule and the 100% isodose line). Prostate coverage was defined in terms of V(100)/V(150)/V(200)/V(300) and D(100)/D(90)/D(50), whereas urethral dosimetry consisted of UV(100)/UV(150)/UV(200) and UD(90)/UD(50). RESULTS: The mean planning target volume to prostate volume ratio varied dramatically (mean 1.29, range 0.99-1.76) with the target length ranging from 3.5 to 4.5 cm. Although the prostate V(100) was >95% in all cases, the V(150) ranged from 29.9% to 92.1% and the V(200) from 6.72% to 52.5%. The urethral V(100) was 100% in all cases with six of the eight brachytherapists limiting the UV(150) to <3%. However, the median urethral dose varied by up to 50%. Treatment margins also varied significantly (average 3.98 mm, range 0.32-7.68 mm). All brachytherapists used extracapsular seeds with five implanting >25% of the seeds in extracapsular locations (range 6.4-58.2%). In addition, significant variability existed in the number of needles, number of seeds, and seed strength. CONCLUSIONS: This study highlights the substantial variability that exists regarding target volume, seed strength, dose homogeneity, treatment margins, and extracapsular seed placement, although prostate brachytherapy prescription doses are uniform. The standardization of pre-implant dosimetry is essential for meaningful multi-institutional comparisons of biochemical outcomes and morbidity.

Brachytherapy↗
PubMed2005

Does anesthesia method affect implant-induced prostate swelling?

OBJECTIVES: To investigate the impact of anesthesia selection on prostate gland swelling, acute toxicity, and implant quality. The outcome of prostate brachytherapy is dependent on the dose intensity and distribution. Preoperative and intraoperative planning are intended to optimize radiation delivery, but do not account for the impact of postoperative swelling on interseed spacing. Factors that increase swelling can be expected to increase the disparity between the intended and actual dose delivery. General anesthesia has been implicated in increased intraoperative bleeding during prostate surgery. METHODS: All iodine prostate implants planned and performed by the same radiation oncologist during a defined period were retrospectively reviewed. Excluded from the study were patients who had undergone preimplantation external beam radiotherapy or androgen deprivation. The remaining cases were analyzed to determine any association between the anesthesia type (general or spinal) and an increase in gland volume (from mapping transrectal ultrasonography to immediate postoperative computed tomography), implant quality (dosimetrically determined by minimal dose received by 90% of the volume [D90] and volume receiving 100% of prescribed dose [V100]), and acute toxicity (urinary retention, perineal/scrotal bruising). RESULTS: A total of 83 implants met the inclusion criteria. The outcomes did not significantly differ in regard to the median volume increase (23% versus 23.5%), D90 (115% versus 113%), V100 (97% versus 96.5%), acute urinary retention (3% versus 4%), or incidence or severity of perineal or scrotal bruising. No correlation was found between anesthesia type and any of the studied outcomes. CONCLUSIONS: Although only a prospective, randomized trial can definitively answer the question, our results suggest that the anesthesia selection for prostate brachytherapy does not influence prostate swelling, acute toxicity, or implant dosimetric quality.

Aged↗
PubMed2003

Critical evaluation of Mirels' rating system for impending pathologic fractures.

This project examined the hypothesis that Mirels' rating system for impending pathologic fractures is reproducible, valid, and applicable across various experience levels and training backgrounds. Twelve true clinical histories and corresponding radiographs for patients with femoral metastatic lesions were reviewed by 53 participants from five experience levels: orthopaedic residents, musculoskeletal radiologists, orthopaedic attendings, fellowship-trained practicing orthopaedic oncologists, and radiation or medical oncologists. Each examiner provided individual and total Mirels' scores and independent determination of impending fracture using clinical judgment. A subset of seven histories without prophylactic fixation provided a natural history group. There was highly significant agreement across experience categories for overall Kappa and for the concordance for individual and overall scores. Kappa analysis showed good agreement for site, moderate agreement for type, and fair agreement for size and pain. There was no significant difference in overall scores across experience levels. The pooled odds ratio favored Mirels rating system over clinical judgment regardless of experience level. Overall sensitivity was 91% and specificity was 35%. Mirels' system seems to be reproducible, valid, and more sensitive than clinical judgment across experience levels. However, although the system is a valuable screening tool, more specific parameters are needed.

Adult↗