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BMC Pregnancy and Childbirth Oct 2021Gonadotropin-releasing hormone antagonist(GnRH-ant) has been shown to have a negative effect on endometrial receptivity. Therefore, the use of lower doses of GnRH-ant...
BACKGROUND
Gonadotropin-releasing hormone antagonist(GnRH-ant) has been shown to have a negative effect on endometrial receptivity. Therefore, the use of lower doses of GnRH-ant during controlled ovarian stimulation (COS) may improve endometrial receptivity and clinical pregnancy rate. However, the GnRH-ant dose is relatively flexible and there is no fixed requirement for guidance. In this retrospective study, we determined the effects of half-dose and full-dose GnRH-ant on IVF-ET outcomes.
METHODS
Of the 316 cycles in the 314 patients analyzed in this study, 149 received GnRH-ant half-dose (Group1), while 167 received GnRH-ant full-dose (Group2). The groups were further classified based on age and BMI. Age subgroups, were divided as age ≤ 35(subgroup A) and age > 35(subgroup B): 180 cycles in subgroup A (107 cycles in subgroup A1,73 cycles in subgroup A2), 136 cycles in subgroup B (42 cycles in subgroup B1,94 cycles in subgroupB2). The subgroups based on BMI were divided as BMI < 25 (subgroup C)and BMI ≥ 25 (subgroup D):208 cycles in subgroup C (94 cycles in subgroup C1,114 cycles in subgroup C2), 108 cycles in subgroup D (55 cycles in subgroup D1,53 cycles in subgroup D2).
RESULTS
The number of fertilized oocytes, superior-quality embryos, clinical pregnancy rate, and live birth rate differed significantly between the two groups. However, the number of retrieved oocytes and available embryos were significantly higher in Group 1 than Group 2 (8.17 ± 4.10 vs. 7.07 ± 4.05, 2.96 ± 2.03 vs. 2.52 ± 1.62, respectively,p<0.05). Differences between the age subgroups were not statistically significant. However, in the subgroups based on BMI, the fertilized oocytes, available embryos, the number of superior-quality embryos, and the live birth rate differed significantly between the four subgroups. The number of retrieved oocytes was higher in subgroup C1 than in subgroup C2 (8.24 ± 4.04 vs. 6.83 ± 3.92,p < 0.05), In addition, the clinical pregnancy rate was slightly higher in subgroup D1 than in subgroup D2(45.45 vs. 24.53%, P < 0.05).
CONCLUSIONS
The results showed that half-dose GnRH-ant was as effective as full-dose GnRH-ant for most patients. Moreover, half-dose GnRH-ant may be more suitable in patients with BMI greater than or equal to 25. The findings of this study need to be validated in a large sample RCT.
TRIAL REGISTRATION
Retrospectively registered.
Topics: Adult; Age Distribution; Birth Rate; Body Mass Index; China; Embryo Transfer; Female; Fertilization in Vitro; Gonadotropin-Releasing Hormone; Hormone Antagonists; Humans; Live Birth; Oocyte Retrieval; Ovulation Induction; Pregnancy; Pregnancy Rate; Retrospective Studies
PubMed: 34706665
DOI: 10.1186/s12884-021-04176-8 -
World Journal of Plastic Surgery Jan 2021Radiotherapy as an adjuvant therapy to surgical resection has shown variable rates of recurrence treating earlobe keloids. The purpose of this study was to describe our...
BACKGROUND
Radiotherapy as an adjuvant therapy to surgical resection has shown variable rates of recurrence treating earlobe keloids. The purpose of this study was to describe our experience with surgical excision followed by high-dose-rate brachytherapy and present our outcomes after 24 months of follow-up.
METHODS
Retrospective chart of 14 patients with 14 earlobe keloids treated with surgical excision followed by high-dose-rate brachytherapy, between January 2015 and May 2016 were enrolled. Database included demographics, Fitzpatrick skin type, laterality, lesion size, and follow-up visits information. Outcomes were assessed in terms of keloid recurrence rates, complications, and patient subjective aesthetical result satisfaction after 24 months of follow-up.
RESULTS
All procedures were completed without complications. Three patients experienced keloid recurrence after 6 (14.28%) and 12 months (7.14%). Three patients experienced mild signs of self-limited post-radiation dermatitis. Self-assessment of aesthetical result was considered "very good" in 71.43% of patients.
CONCLUSION
Surgical excision followed by high-dose-rate brachytherapy is secure and effective to treat earlobe keloids, and can be considered a first line combined treatment. Larger clinical trials comparing different irradiation protocols are still needed.
PubMed: 33833958
DOI: 10.29252/wjps.10.1.78 -
Medical Physics Mar 2022Compared to CONV-RT (with conventional dose rate), FLASH-RT (with ultra-high dose rate) can provide biological dose sparing for organs-at-risk (OARs) via the so-called...
PURPOSE
Compared to CONV-RT (with conventional dose rate), FLASH-RT (with ultra-high dose rate) can provide biological dose sparing for organs-at-risk (OARs) via the so-called FLASH effect, in addition to physical dose sparing. However, the FLASH effect only occurs, when both dose and dose rate meet certain minimum thresholds. This work will develop a simultaneous dose and dose rate optimization (SDDRO) method accounting for both FLASH dose and dose rate constraints during treatment planning for pencil-beam-scanning proton therapy.
METHODS
SDDRO optimizes the FLASH effect (specific to FLASH-RT) as well as the dose distribution (similar to CONV-RT). The nonlinear dose rate constraint is linearized, and the reformulated optimization problem is efficiently solved via iterative convex relaxation powered by alternating direction method of multipliers. To resolve and quantify the generic tradeoff of FLASH-RT between FLASH and dose optimization, we propose the use of FLASH effective dose based on dose modifying factor (DMF) owing to the FLASH effect.
RESULTS
FLASH-RT via transmission beams (TB) (IMPT-TB or SDDRO) and CONV-RT via Bragg peaks (BP) (IMPT-BP) were evaluated for clinical prostate, lung, head-and-neck (HN), and brain cases. Despite the use of TB, which is generally suboptimal to BP for normal tissue sparing, FLASH-RT via SDDRO considerably reduced FLASH effective dose for high-dose OAR adjacent to the target. For example, in the lung SBRT case, the max esophageal dose constraint 27 Gy was only met by SDDRO (24.8 Gy), compared to IMPT-BP (35.3 Gy) or IMPT-TB (36.6 Gy); in the brain SRS case, the brain constraint V12Gy≤15cc was also only met by SDDRO (13.7cc), compared to IMPT-BP (43.9cc) or IMPT-TB (18.4cc). In addition, SDDRO substantially improved the FLASH coverage from IMPT-TB, e.g., an increase from 37.2% to 67.1% for lung, from 39.1% to 58.3% for prostate, from 65.4% to 82.1% for HN, from 50.8% to 73.3% for the brain.
CONCLUSIONS
Both FLASH dose and dose rate constraints are incorporated into SDDRO for FLASH-RT that jointly optimizes the FLASH effect and physical dose distribution. FLASH effective dose via FLASH DMF is introduced to reconcile the tradeoff between physical dose sparing and FLASH sparing, and quantify the net effective gain from CONV-RT to FLASH-RT.
Topics: Humans; Male; Organs at Risk; Proton Therapy; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Intensity-Modulated
PubMed: 34800301
DOI: 10.1002/mp.15356 -
Strahlentherapie Und Onkologie : Organ... Jun 2022In the beam penumbra of stereotactic body radiotherapy volumes, dose rate effects in implantable cardioverter-defibrillators (ICDs) may be the predominant cause for...
PURPOSE
In the beam penumbra of stereotactic body radiotherapy volumes, dose rate effects in implantable cardioverter-defibrillators (ICDs) may be the predominant cause for failures in the absence of neutron-generating photon energies. We investigate such dose rate effects in ICDs and provide evidence for safe use of lung tumor stereotactic radioablation with flattening filter free (FFF) and flattened 6 Megavolt (MV) beams in ICD-bearing patients.
METHODS
Sixty-two ICDs were subjected to scatter radiation in 1.0, 2.5, and 7.0 cm distance to 100 Gy within a 5 × 5 cm radiation field. Radiation was applied with 6 MV FFF beams (constant dose rate of 1400 cGy/min) and flattened (FLAT) 6 MV beams (430 cGy/min). Local dose rates (LDR) at the position of all ICDs were measured. All ICDs were monitored continuously.
RESULTS
With 6 MV FFF beams, ICD errors occurred at distances of 1.0 cm (LDR 46.8 cGy/min; maximum ICD dose 3.4 Gy) and 2.5 cm (LDR 15.6 cGy/min; 1.1 Gy). With 6 MV FLAT beams, ICD errors occurred only at 1 cm distance (LDR 16.8 cGy/min; 3.9 Gy). No errors occurred at an LDR below 7 cGy/min, translating to a safe distance of 2.5 cm (1.5 Gy) in flattened and 7 cm (0.4 Gy) in 6 MV FFF beams.
CONCLUSION
A LDR in ICDs larger than 7 cGy/min may cause ICD malfunction. At identical LDR, differences between 6 MV FFF and 6 MV FLAT beams do not yield different rates of malfunction. The dominant reason for ICD failures could be the LDR and not the total dose to the ICD. For most stereotactic treatments, it is recommended to generate a planning risk volume around the ICD in which LDR larger than 7 cGy/min are avoided.
Topics: Defibrillators, Implantable; Humans; Proton Therapy; Radiosurgery; Radiotherapy Dosage; Treatment Outcome
PubMed: 35267050
DOI: 10.1007/s00066-022-01911-8 -
International Journal of Radiation... 2021Carcinogenic effects of radiation are often assumed to be universally understood, more often than, for example, carcinogenic effects of many different chemicals. This... (Review)
Review
Carcinogenic effects of radiation are often assumed to be universally understood, more often than, for example, carcinogenic effects of many different chemicals. This in turn leads to an assumption that any dose of radiation, delivered at any dose rate, poses a serious health challenge. This remains an issue of dispute and low dose radiation research is focused on understanding whether these exposures contribute to cancer incidence. This review is focused on the low linear energy transfer (low LET) radiation exposures for which the data is the most abundant in recent years. Review of the literature between 2008 and today, highlighting some of the most diverse studies in low dose research. Low dose and low dose rate, low LET ionizing radiation animal studies suggest that the effects of exposure very much depend on animal genotype and health status. Only the integration of all of the data from different models and studies will lead to a fuller understanding of low dose radiation effects. Therefore, we hope to see an increase in international archival efforts and exchange of raw data information opening the possibilities for new types of meta analyses.
Topics: Animals; Carcinogenesis; Dose-Response Relationship, Radiation; Humans; Linear Energy Transfer; Neoplasms, Radiation-Induced
PubMed: 33289582
DOI: 10.1080/09553002.2020.1859155 -
International Journal of Molecular... Jun 2022Accurate knowledge of the relative biological effectiveness (RBE) and its dependencies is crucial to support modern ion beam therapy and its further development....
Accurate knowledge of the relative biological effectiveness (RBE) and its dependencies is crucial to support modern ion beam therapy and its further development. However, the influence of different dose rates of the reference radiation and ion beam are rarely considered. The ion beam RBE-model within our "UNIfied and VERSatile bio response Engine" (UNIVERSE) is extended by including DNA damage repair kinetics to investigate the impact of dose-rate effects on the predicted RBE. It was found that dose-rate effects increase with dose and biological effects saturate at high dose-rates, which is consistent with data- and model-based studies in the literature. In a comparison with RBE measurements from a high dose in-vivo study, the predictions of the presented modification were found to be improved in comparison to the previous version of UNIVERSE and existing clinical approaches that disregard dose-rate effects. Consequently, DNA repair kinetics and the different dose rates applied by the reference and ion beams might need to be considered in biophysical models to accurately predict the RBE. Additionally, this study marks an important step in the further development of UNIVERSE, extending its capabilities in giving theoretical guidance to support progress in ion beam therapy.
Topics: DNA Repair; Kinetics; Relative Biological Effectiveness
PubMed: 35682947
DOI: 10.3390/ijms23116268 -
Clinical Oncology (Royal College of... May 2022Following adoption of moderately hypofractionated radiotherapy as a standard for localised prostate cancer, ultrahypofractioned radiotherapy delivered in five to seven... (Review)
Review
Following adoption of moderately hypofractionated radiotherapy as a standard for localised prostate cancer, ultrahypofractioned radiotherapy delivered in five to seven fractions is rapidly being embraced by clinical practice and international guidelines. However, the question remains: how low can we go? Can radiotherapy for prostate cancer be delivered in fewer than five fractions? The current review summarises the evidence that radiotherapy for localised prostate cancer can be safely and effectively delivered in fewer than five fractions using high dose rate brachytherapy or stereotactic body radiotherapy. We also discuss important lessons learned from the single-fraction high dose rate brachytherapy experience.
Topics: Brachytherapy; Humans; Male; Prostatic Neoplasms; Radiation Dose Hypofractionation; Radiosurgery
PubMed: 34961659
DOI: 10.1016/j.clon.2021.12.006 -
Medical Physics Dec 2022The combined use of Bragg peak (BP) and shoot-through (ST) beams has previously been shown to increase the normal tissue volume receiving FLASH dose rates while...
PURPOSE
The combined use of Bragg peak (BP) and shoot-through (ST) beams has previously been shown to increase the normal tissue volume receiving FLASH dose rates while maintaining dose conformality compared to conventional intensity-modulated proton therapy (IMPT) methods. However, the fixed beam optimization method has not considered the effects of beam orientation on the dose and dose rates. To maximize the proton FLASH effect, here, we incorporate dose rate objectives into our beam orientation optimization framework.
METHODS
From our previously developed group-sparsity dose objectives, we add upper and lower dose rate terms using a surrogate dose-averaged dose rate definition and solve using the fast-iterative shrinking threshold algorithm. We compare the dosimetry for three head-and-neck cases between four techniques: (1) spread-out BP IMPT (BP), (2) dose rate optimization using BP beams only (BP-DR), (3) dose rate optimization using ST beams only (ST-DR), and (4) dose rate optimization using combined BP and ST (BPST-DR), with the goal of sparing organs at risk without loss of tumor coverage and maintaining high dose rate within a 10 mm region of interest (ROI) surrounding the clinical target volume (CTV).
RESULTS
For BP, BP-DR, ST-DR, and BPST-DR, CTV homogeneity index and Dmax were found to be on average 0.886, 0.867, 0.687, and 0.936 and 107%, 109%, 135%, and 101% of prescription, respectively. Although ST-DR plans were not able to meet dosimetric standards, BPST-DR was able to match or improve either maximum or mean dose in the right submandibular gland, left and right parotids, constrictors, larynx, and spinal cord compared to BP plans. Volume of ROIs receiving greater than 40 Gy/s ( was 51.0%, 91.4%, 95.5%, and 92.1% on average.
CONCLUSIONS
The dose rate techniques, particularly BPST-DR, were able to significantly increase dose rate without compromising physical dose compared with BP. Our algorithm efficiently selects beams that are optimal for both dose and dose rate.
Topics: Humans; Proton Therapy; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Neoplasms; Protons; Radiotherapy, Intensity-Modulated; Organs at Risk
PubMed: 36222217
DOI: 10.1002/mp.16009 -
Scientific Reports Dec 2022The Radiological Research Accelerator Facility has modified a decommissioned Varian Clinac to deliver ultra-high dose rates: operating in 9 MeV electron mode (FLASH...
The Radiological Research Accelerator Facility has modified a decommissioned Varian Clinac to deliver ultra-high dose rates: operating in 9 MeV electron mode (FLASH mode), samples can be irradiated at a Source-Surface Distance (SSD) of 20 cm at average dose rates of up to 600 Gy/s (3.3 Gy per 0.13 µs pulse, 180 pulses per second). In this mode multiple pulses are required for most irradiations. By modulating pulse repetition rate and irradiating at SSD = 171 cm, dose rates below 1 Gy/min can be achieved, allowing comparison of FLASH and conventional irradiations with the same beam. Operating in 6 MV photon mode, with the conversion target removed (SuperFLASH mode), samples are irradiated at higher dose rates (0.2-150 Gy per 5 µs pulse, 360 pulses per second) and most irradiations can be performed with a single very high dose rate pulse. In both modes we have seen the expected inverse relation between dose rate and irradiated area, with the highest dose rates obtained for beams with a FWHM of about 2 cm and ± 10% uniformity over 1 cm diameter. As an example of operation of the ultra-high dose rate FLASH irradiator, we present dose rate dependence of dicentric chromosome yields.
Topics: Particle Accelerators; Photons; Electrons; Radiotherapy Dosage; Radiometry
PubMed: 36550150
DOI: 10.1038/s41598-022-19211-7 -
Current Issues in Molecular Biology Aug 2023The output constancy of the accelerator used for boron neutron capture therapy (BNCT) is essential to ensuring anti-tumor efficacy and safety. BNCT as currently...
The output constancy of the accelerator used for boron neutron capture therapy (BNCT) is essential to ensuring anti-tumor efficacy and safety. BNCT as currently practiced requires a wide variety of beam quality assessments to ensure that RBE dose errors are maintained within 5%. However, the necessity of maintaining a constant beam dose rate has not been fully discussed. We therefore clarified the effect of different physical dose rates of the accelerator BNCT on biological effects. SAS and A172 cells exposed to B-boronophenylalanine were irradiated using a neutron beam (normal operating current, 100 μA) at the Aomori Quantum Science Center. Thermal neutron flux was attenuated to 50.0 ± 0.96% under 50 μA irradiation compared to that under 100 μA irradiation. Cells were given physical doses of 1.67 and 3.36 Gy at 30 and 60 mC, respectively, and survival was significantly increased after 50 μA irradiation for both cell types ( = 0.0052 for SAS; = 0.046 for A172, for 60 mC). Differences in accelerator BNCT beam dose rates have non-negligible effects on biological effects. Dose rate fluctuations and differences should not be easily permitted to obtain consistent biological effects.
PubMed: 37754225
DOI: 10.3390/cimb45090441