Monte Carlo based dosimetry of extraoral photobiomodulation for prevention of oral mucositis.
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ABSTRACT:
SUBMITTER: Yaroslavsky AN
PROVIDER: S-EPMC10665335 | biostudies-literature | 2023 Nov
REPOSITORIES: biostudies-literature
Publications
Monte Carlo based dosimetry of extraoral photobiomodulation for prevention of oral mucositis.
Yaroslavsky Anna N AN Iorizzo Tyler W TW Juliano Amy F AF Adnan Ather A Carroll James D JD Sonis Stephen T ST Duncan Christine N CN London Wendy B WB Treister Nathaniel S NS
Scientific reports 20231122 1
Photobiomodulation therapy (PBMT) is recommended for prevention and treatment of oral mucositis, a painful condition that occurs in cancer patients. Intraoral PBMT is limited to treating distal oral mucosa and oropharynx. Extraoral PBMT may provide a more efficient intervention. The goal of this study was to develop a clinically viable protocol for extraoral PBMT. Monte Carlo modeling was used to predict the distribution of 850 nm light for four treatment sites, using anatomical data obtained fr ...[more]
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Project description:PurposeTo assess the safety and efficacy of prophylactic extraoral photobiomodulation (PBM) for the prevention of oral and oropharyngeal mucositis (OM) on clinical outcomes and survival in patients with oral cavity and oropharyngeal squamous cell carcinoma (OOPSCC).MethodsOOPSCC patients who received radiotherapy (RT) were prospectively randomized to two groups: prophylactic extraoral PBM and placebo. OM grade (NCI), pain (VAS), analgesia, and anti-inflammatory prescriptions were assessed weekly. Quality of life questionnaires (QoL) were performed at the first and last day of RT. Following RT, participants were evaluated quarterly for oncological outcomes follow-up.ResultsFifty-five patients met the inclusion criteria. The first occurrence of OM was observed at week 1, for the placebo group (p = 0.014). Later, OM onset and severity was observed for the PBM group, with first occurrence at week 2 (p = 0.009). No difference in severe OM incidence was observed (p > 0.05). Lower mean pain score was noted at week 7 for the PBM group (2.1) compared to placebo group (4.5) (p = 0.009). Less analgesics (week 3; p = 0.009/week 7; p = 0.02) and anti-inflammatory prescription (week 5; p = 0.0346) were observed for the PBM group. Better QoL scores were observed for the PBM group at last day of RT (p = 0.0034). No difference in overall survival among groups was observed in 1 year of follow-up (p = 0.889).ConclusionProphylactic extraoral PBM can delay OM onset, reduce pain, and reduce analgesic and anti-inflammatory prescription requirements. Extraoral PBM was associated with better QoL. There was no evidence of PBM impact on oncological outcomes.Trial registrationTRN:RBR-4w4swx (date of registration: 01/20/2020).
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Project description:PurposeTo obtain individualized internal doses with a Monte Carlo (MC) method in patients undergoing diagnostic [18F]FCH-PET studies and to compare such doses with the MIRD method calculations.MethodsA patient cohort of 17 males were imaged after intravenous administration of a mean [18F]FCH activity of 244.3 MBq. The resulting PET/CT images were processed in order to generate individualized input source and geometry files for dose computation with the MC tool GATE. The resulting dose estimates were studied and compared to the MIRD method with two different computational phantoms. Mass correction of the S-factors was applied when possible. Potential sources of uncertainty were closely examined: the effect of partial body images, urinary bladder emptying, and biokinetic modeling.ResultsLarge differences in doses between our methodology and the MIRD method were found, generally in the range ±25%, and up to ±120% for some cases. The mass scaling showed improvements, especially for non-walled and high-uptake tissues. Simulations of the urinary bladder emptying showed negligible effects on doses to other organs, with the exception of the prostate. Dosimetry based on partial PET/CT images (excluding the legs) resulted in an overestimation of mean doses to bone, skin, and remaining tissues, and minor differences in other organs/tissues. Estimated uncertainties associated with the biokinetics of FCH introduce variations of cumulated activities in the range of ±10% in the high-uptake organs.ConclusionsThe MC methodology allows for a higher degree of dosimetry individualization than the MIRD methodology, which in some cases leads to important differences in dose values. Dosimetry of FCH-PET based on a single partial PET study seems viable due to the particular biokinetics of FCH, even though some correction factors may need to be applied to estimate mean skin/bone doses.
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Project description:BackgroundGiven the suffering experienced by cancer patients, effective solutions must be found to prevent painful and debilitating side effects of anti-cancer treatment. This trial aims to study the effect of preconditioning with photobiomodulation in preventing oral mucositis and xerostomia in cancer patients undergoing chemotherapy alone for the first time, and to examine its role in improving patients' quality of life.Materials and methodsThis is a prospective, randomized, double-blind clinical trial including 45 patients divided into three age- and sex-matched groups. Group 1 received basic oral care instructions before undergoing chemotherapy. Group 2 received basic oral care instructions plus photobiomodulation using an intraoral 650 nm diode laser. Group 3 received basic oral care instructions plus photobiomodulation using a 650 nm diode laser intraorally and a 980 nm diode laser extraorally.ResultsAfter one week of follow-up, 73.3% of patients in Group 2 and 80% in Group 3 did not develop oral mucositis. The remaining patients in both groups experienced only mild erythema. In contrast, all patients in Group 1 developed oral mucositis, ranging from mild erythema to ulceration greater than 3 cm². After two weeks of follow-up, 80% of patients in Group 2 and 86.7% in Group 3 remained free of oral mucositis. The remaining patients in both groups experienced only mild erythema. In contrast, 93.3% of patients in Group 1 developed oral mucositis, with cases ranging from mild erythema to ulcers larger than 3 cm². There were statistically significant differences between the three groups in oral mucositis assessment scale after one week and after two weeks (p < 0.001). Specifically, ulcerative mucositis was not observed in both laser groups, while it was observed in 13.3% of patients in Group 1. However, these differences were not statistically significant (p = 0.129). Regarding Late Effects in Normal Tissue (LENT-SOMA) scale, there was a statistically significant difference between the three groups studied (p = 0.037). There was also a statistically significant difference in the Oral Health Impact Profile (OHIP-14) between the three groups studied (p = 0.003 after one week, p = 0.023 after two weeks).ConclusionPreconditioning before starting chemotherapy, whether with the intraoral red laser alone or in combination with the extraoral infrared laser, has shown significant results in preventing oral mucositis and dry mouth, and it has also played a major role in improving patients' quality of life.Trial registrationThis trial was registered in ISRCTN registry under no ISRCTN70634383 ( https://doi.org/10.1186/ISRCTN70634383 ) on 24/07/2023.
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Project description:BACKGROUND:Intrahepatic dosimetry is paramount to optimize radioembolization treatment accuracy using radioactive holmium-166 microspheres (166Ho). This requires a practical protocol that combines quantitative imaging of microsphere distribution with automated and robust delineation of the volumes of interest. To this end, we propose a dual isotope single photon emission computed tomography (SPECT) protocol based on 166Ho therapeutic microspheres and technetium-99?m (99mTc) stannous phytate, which accumulates in healthy liver tissue. This protocol may allow accurate and automatic estimation of tumor-absorbed dose and healthy liver-absorbed dose. The current study focuses on a Monte Carlo-based reconstruction framework that inherently corrects for scatter crosstalk between the 166Ho and 99mTc imaging. To demonstrate the feasibility of the method, it is evaluated with realistic phantom experiments and patient data. METHODS:The Utrecht Monte Carlo System (UMCS) was extended to include detailed modeling of crosstalk interactions between 99mTc and 166Ho. First, 99mTc images were reconstructed including energy window-based corrections for 166Ho downscatter. Next, 99mTc downscatter in the 81-keV 166Ho window was Monte Carlo simulated to allow quantitative reconstruction of the 166Ho images. The accuracy of the 99mTc-downscatter modeling was evaluated by comparing measurements with simulations. In addition, the ratio between 99mTc and 166Ho yielding the best 166Ho dose estimates was established and the quantitative accuracy was reported. RESULTS:Given the same level of activity, 99mTc contributes twice as many counts to the 81-keV window than 166Ho, and four times as many counts to the 140-keV window, applying a 166Ho/99mTc ratio of 5:1 yielded a high accuracy in both 166Ho and 99mTc reconstruction. Phantom experiments revealed that the accuracy of quantitative 166Ho activity recovery was reduced by 10% due to the presence of 99mTc. Twenty iterations (8 subsets) of the SPECT/CT reconstructions were considered feasible for clinical practice. Applicability of the proposed protocol was shown in a proof-of-concept case. CONCLUSION:A novel 166Ho/99mTc dual-isotope protocol for automatic dosimetry compensates accurately for downscatter and allows for the addition of 99mTc without compromising 166Ho SPECT image quality.
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