Effect of Lithotripsy on Holmium:YAG Optical Beam Profile
Bibliographic record
Abstract
PURPOSE: To determine the effect of holmium:YAG lithotripsy on the optical beam profile. MATERIALS AND METHODS: Beam profiles of the laser light from holmium:YAG optical fiber systems were characterized with a pyroelectric camera. Beam profiles were measured with 272-microm and 365-microm optical fibers both straight and bent to simulate lower-pole ureteronephroscopy. Struvite calculi were irradiated. Beam profiles and energy outputs were characterized for the fibers before and after ablation. Ablation crater geometry was characterized with optical coherence tomography. RESULTS: Undamaged, straight fibers produced a near-Gaussian beam profile. Craters showed a similar near-Gaussian shape. Undamaged, bent 272-microm fibers produced a near-Gaussian beam but slightly flatter profile than the straight fiber. The bent 272-microm fiber transmitted 99% to 100% of the energy, similar to the 100% transmission of the straight fibers. After ablation, measured energy output dropped by 30% within 50 pulses at 0.2 J pulse energy. The damaged fibers produced irregular beam profiles with hot spots. Craters showed irregular contours. CONCLUSIONS: During Ho:YAG lithotripsy, the beam profile at the optical fiber tip approaches a Gaussian distribution. This shape corresponds to the crater produced on the stone surface. With further ablation, the beam profile becomes erratic and unpredictable, with loss of lithotripsy efficiency. The findings provide further insight into the photothermal mechanism of Ho:YAG lithotripsy.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".