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Radiotherapy and Oncology : Journal of... Jun 2024As no guidelines for pencil beam scanning (PBS) proton therapy (PT) of paediatric posterior fossa (PF) tumours exist to date, this study investigated planning techniques...
BACKGROUND AND PURPOSE
As no guidelines for pencil beam scanning (PBS) proton therapy (PT) of paediatric posterior fossa (PF) tumours exist to date, this study investigated planning techniques across European PT centres, with special considerations for brainstem and spinal cord sparing.
MATERIALS AND METHODS
A survey and a treatment planning comparison were initiated across nineteen European PBS-PT centres treating paediatric patients. The survey assessed all aspects of the treatment chain, including but not limited to delineations, dose constraints and treatment planning. Each centre planned two PF tumour cases for focal irradiation, according to their own clinical practice but based on common delineations. The prescription dose was 54 Gy(RBE) for Case 1 and 59.4 Gy(RBE) for Case 2. For both cases, planning strategies and relevant dose metrics were compared.
RESULTS
Seventeen (89 %) centres answered the survey, and sixteen (80 %) participated in the treatment planning comparison. In the survey, thirteen (68 %) centres reported using the European Particle Therapy Network definition for brainstem delineation. In the treatment planning study, while most centres used three beam directions, their configurations varied widely across centres. Large variations were also seen in brainstem doses, with a brainstem near maximum dose (D2%) ranging from 52.7 Gy(RBE) to 55.7 Gy(RBE) (Case 1), and from 56.8 Gy(RBE) to 60.9 Gy(RBE) (Case 2).
CONCLUSION
This study assessed the European PBS-PT planning of paediatric PF tumours. Agreement was achieved in e.g. delineation-practice, while wider variations were observed in planning approach and consequently dose to organs at risk. Collaboration between centres is still ongoing, striving towards common guidelines.
PubMed: 38942120
DOI: 10.1016/j.radonc.2024.110414 -
Physics in Medicine and Biology Jun 2024Proton therapy is a limited resource and is typically not available to metastatic cancer patients. Combined proton-photon therapy (CPPT), where most fractions are...
Proton therapy is a limited resource and is typically not available to metastatic cancer patients. Combined proton-photon therapy (CPPT), where most fractions are delivered with photons and only few with protons, represents an approach to distribute proton resources over a larger patient population. In this study, we consider stereotactic radiotherapy of multiple brain or liver metastases, and develop an approach to optimally take advantage of a single proton fraction by optimizing the proton and photon dose contributions to each individual metastasis. CPPT treatments must balance two competing goals: 1) deliver a larger dose in the proton fractions to reduce integral dose, and 2) fractionate the dose in the normal tissue between metastases, which requires using the photon fractions. Such CPPT treatments are generated by simultaneously optimizing IMPT and IMRT plans based on their cumulative biologically effective dose (BED). The dose contributions of the proton and photon fractions to each individual metastasis are handled as additional optimization variables in the optimization problem. The method is demonstrated for two patients with 29 and 30 brain metastases, and two patients with 4 and 3 liver metastases. Optimized CPPT plans increase the proton dose contribution to most of the metastases, while using photons to fractionate the dose around metastases which are large or located close to critical structures. On average, the optimized CPPT plans reduce the mean brain BEDby 29% and the mean liver BEDby 42% compared to IMRT-only plans. Thereby, the CPPT plans approach the dosimetric quality of IMPT-only plans, for which the mean brain BEDand mean liver BEDare reduced by 28% and 58%, respectively, compared to IMRT-only plans. CPPT with optimized proton and photon dose contributions to individual metastases may benefit selected metastatic cancer patients without tying up major proton resources. .
PubMed: 38942008
DOI: 10.1088/1361-6560/ad5d48 -
Physics in Medicine and Biology Jun 2024Particle therapy treatments are currently limited by uncertainties of the delivered dose. Verification techniques like Prompt-Gamma-Timing-based Stopping Power...
Particle therapy treatments are currently limited by uncertainties of the delivered dose. Verification techniques like Prompt-Gamma-Timing-based Stopping Power Estimation (PGT-SPE) may allow for reduction of safety margins in treatment planning. Approach: From Prompt-Gamma-Timing measurements, we reconstruct the spatiotemporal distribution of prompt gamma emissions, which is linked to the average motion of the primary particles. The stopping power is determined by fitting a model of the average particle motion. Here, we compare a previously published implementation of the particle motion model with an alternative formulation and present two formulations to automatically select the hyperparameters of our procedure. The performance was assessed using Monte-Carlo simulations of proton beams (60 MeV to 219 MeV) impinging on a homogeneous PMMA phantom. Main results: The range was successfully determined within a standard deviation of 3 mm for proton beam energies from 70 MeV to 219 MeV. Stopping power estimates showed errors below 5 % for beam energies above 160 MeV. At lower energies, the estimation performance degraded to unsatisfactory levels due to the short range of the protons. The new motion model improved the estimation performance by up to 5 % for beam energies from 100 MeV to 150 MeV with mean errors ranging from 6 % to 18 %. The automated hyperparameter optimization matched the average error of previously reported manual selections, while significantly reducing the outliers. Significance: The data-driven hyperparameter optimization allowed for a reproducible and fast evaluation of our method. The updated motion model and evaluation at new beam energies bring us closer to applying PGT-SPE in more complex scenarios. Direct comparison of stopping power estimates between treatment planning and measurements during irradiation would offer a more direct verification than other secondary-particle-based techniques.
PubMed: 38941994
DOI: 10.1088/1361-6560/ad5d4b -
Oral Oncology Jun 2024
PubMed: 38941874
DOI: 10.1016/j.oraloncology.2024.106912 -
Przeglad Gastroenterologiczny 2024The eradication rate of () has decreased due to antibiotics resistance and inadequate acid suppression. Vonoprazan is a novel potassium-competitive acid blocker...
INTRODUCTION
The eradication rate of () has decreased due to antibiotics resistance and inadequate acid suppression. Vonoprazan is a novel potassium-competitive acid blocker (P-CAB), which has a rapid and sustained acid inhibitory effect and may be more effective than conventional proton pump inhibitors (PPIs) in eradication.
AIM
to study the efficacy and safety of vonoprazan as a component of first-line eradication treatment compared with conventional PPI-based therapy.
MATERIAL AND METHODS
This randomised (one to one) non-blinded study was conducted on 400 consecutive proven infected patients, of whom 200 received vonoprazan-based triple therapy, while 200 patients received PPI-based triple therapy for 14 days. The study outcomes were evaluated as eradication rate and adverse events in both patient groups.
RESULTS
The eradication rate was 86% in the vonoprazan group and 74.5% in the PPI group. The vonoprazan eradication rate was significantly higher than that of PPIs ( = 0.004). There was no significant difference regarding adverse events between both patient groups.
CONCLUSIONS
Vonoprazan-based therapy was more effective than PPI-based therapy as a first-line eradication treatment. Vonoprazan was generally safe and well tolerated.
PubMed: 38939071
DOI: 10.5114/pg.2024.139426 -
Przeglad Gastroenterologiczny 2024Proton pump inhibitors (PPIs) are effective drugs used for multiple gastrointestinal complications. They are commonly used in both hospitalised and outpatients. However,...
INTRODUCTION
Proton pump inhibitors (PPIs) are effective drugs used for multiple gastrointestinal complications. They are commonly used in both hospitalised and outpatients. However, little is known about its utilisation pattern in ambulatory patients.
AIM
To evaluate the inexpedient continuous use of PPIs in patients with respect to treatment duration.
MATERIAL AND METHODS
A cross-sectional observational study was conducted from January 2018 to November 2019 in Khyber Pakhtunkhwa, Pakistan. Regular proton pump inhibitor users were identified through patient histories.
RESULTS
During the study period, 171 patients were included using a non-probability consecutive sampling technique, who were using regular proton pump inhibitors for a longer duration, i.e. from 3 months to 15 years. The highest proportion (42.8%) were using PPI regularly from 3 months to 1 year followed by 22.9% for 1-2 years, 12.0% for 2-3 years, 7.8% for 3-4 years, 4.2% for 4-5 years, and 10.24% for > 5 years. Omeprazole and esomeprazole were the most commonly used drugs, with 71.1% and 23.5% prevalence, respectively. A total of 33.73% of patients had continued PPI use on their own after initially being prescribed by the physician.
CONCLUSIONS
It can be deduced that PPIs are used in outpatients beyond standard treatment guidelines. The inexpedient continuous use of proton pump inhibitors is of concern due to the risk of developing adverse effects. Therefore, patient counselling and periodic monitoring must be carried out to prevent the irrational use of PPIs.
PubMed: 38939068
DOI: 10.5114/pg.2024.139429 -
Biomedical Reports Aug 2024Despite proton pump inhibitors (PPIs) being generally safe, there are questions about their potential long-term complications. The present study aimed to investigate the...
Despite proton pump inhibitors (PPIs) being generally safe, there are questions about their potential long-term complications. The present study aimed to investigate the association between PPI therapy and the incidence of hepatic steatosis and liver fibrosis in the outpatient population of the United States. The present study included 7,395 individuals aged ≥20 years who underwent hepatic vibration-controlled transient elastography (VCTE) examination. The data were obtained from the January 2017 to March 2020 pre-pandemic National Health and Nutrition Examination Survey. Among the 7,395 adults who were included (mean age, 50.59 years; 3,656 male), 9.8% were prescribed PPIs. Following multivariable adjustment, the use of PPIs was significantly associated with hepatic steatosis [odds ratio (OR), 1.25; 95% confidence interval (CI), 1.02-1.53]. Prolonged use of PPIs was found to increase the risk of developing hepatic steatosis over time (P=0.006). Sensitivity analyses using different definitions of hepatic steatosis, such as a controlled attenuation parameter ≥285 dB/m (OR, 1.19; CI, 1.01-1.40), non-alcoholic fatty liver disease (OR, 1.50; 95% CI, 1.16-1.93) and metabolic dysfunction-associated steatotic liver disease (OR, 1.26; 95% CI, 1.05-1.52), consistently demonstrated an association between PPI prescription and hepatic steatosis. The administration of PPI therapy was linked with hepatic steatosis in US adults, although no significant association was observed with liver stiffness, as determined by VCTE.
PubMed: 38938738
DOI: 10.3892/br.2024.1804 -
In Vivo (Athens, Greece) 2024We report on a case of locally advanced hepatocellular carcinoma (HCC) accompanied by an inferior vena cava tumor thrombus (IVCTT), treated successfully with proton-beam...
BACKGROUND/AIM
We report on a case of locally advanced hepatocellular carcinoma (HCC) accompanied by an inferior vena cava tumor thrombus (IVCTT), treated successfully with proton-beam therapy (PBT).
CASE REPORT
A 63-year-old male presented with a primary, single HCC with IVCTT, without metastasis to the intrahepatic region, lymph nodes, or distant organs. The clinical staging was identified as T4N0M0 Stage IIIB. The patient's liver function was classified as Child-Pugh class A (score: 6), with a modified albumin-bilirubin (mALBI) grade of 2a. The patient had liver cirrhosis due to non-alcoholic steatohepatitis. Magnetic resonance imaging revealed a nodular tumor measuring 13.2×8.9×9.8 cm across segments 1, 6, 7, and 8, along with IVCTT. The patient received PBT, with a total dose of 72.6 Gy (relative biological effectiveness) delivered in 22 fractions. Throughout the PBT treatment, the patient experienced no acute toxicities and completed the therapy as planned. Twelve months following PBT, the patient was alive without evidence of local recurrence, lymph node involvement, or distant organ metastasis. The only late toxicity observed was a mild worsening of the mALBI grade.
CONCLUSION
We observed a favorable local response with manageable toxicities in a patient with locally advanced HCC and IVCTT treated with PBT. While this is a single case report, our findings suggest that PBT could be considered a viable treatment option for HCC with IVCTT.
Topics: Humans; Male; Liver Neoplasms; Carcinoma, Hepatocellular; Middle Aged; Proton Therapy; Vena Cava, Inferior; Treatment Outcome; Magnetic Resonance Imaging; Neoplasm Staging; Venous Thrombosis
PubMed: 38936928
DOI: 10.21873/invivo.13667 -
International Journal of Radiation... Jun 2024Pencil-beam scanning proton therapy has been considered as a potential modality for the 3D form of spatially-fractionated-radiation-therapy called lattice therapy....
PURPOSE
Pencil-beam scanning proton therapy has been considered as a potential modality for the 3D form of spatially-fractionated-radiation-therapy called lattice therapy. However, few practical solutions have been introduced in the clinic. Existing limitations include degradation in plan quality and robustness when using single-field versus multifield lattice plans, respectively. We propose a practical and robust proton lattice (RPL) planning method using multifield and evaluate its dosimetric characteristics compared to clinically acceptable photon lattice plans.
METHODS
Seven cases previously treated with photon lattice therapy were used to evaluate a novel RPL planning technique using two-orthogonal beams: a primary beam (PB) and a robust complementary beam (RCB) that deliver 67% and 33%, respectively, of the prescribed dose to vertices inside the gross-target-volume (GTV). Only RCB is robustly optimized for setup and range uncertainties. The number and volume of vertices, peak-to-valley dose ratios (PVDRs), and volume of low dose to GTV of proton and photon plans were compared. The RPL technique was then used in treatment of two patients and their dosimetric parameters are reported.
RESULTS
The RPL strategy was able to achieve the clinical planning goals. Compared to previously-treated photon plans, the average number of vertices increased by 30%, average vertex volume by 49% (18.2±25.9cc vs. 12.2±14.5cc, P=0.21), and higher PVDR (10.5±4.8 vs. 2.5±0.9, P<0.005) was achieved. In addition, RPL plans show more conformal dose with less low-dose to GTV (V30%: 60.9±7.2% vs. 81.6±13.9% and V10%: 88.3±4.5% vs. 98.6±3.6% [P<0.01]). The RPL plan for two treated patients showed PVDRs of 4.61 and 14.85 with vertices-to-GTV ratios of 1.52% and 1.30%, respectively.
CONCLUSION
A novel RPL planning strategy using a pair of orthogonal beams was developed and successfully translated to the clinic. The proposed method can generate better quality plans, a higher number of vertices, and higher PVDRs than currently used photon lattice plans.
PubMed: 38936634
DOI: 10.1016/j.ijrobp.2024.06.009 -
Journal of Clinical Medicine Jun 2024: Proton pump inhibitor (PPI) therapy is well-established for its effectiveness in reducing re-bleeding in high-risk peptic ulcer patients following endoscopic...
: Proton pump inhibitor (PPI) therapy is well-established for its effectiveness in reducing re-bleeding in high-risk peptic ulcer patients following endoscopic hemostasis. Vonoprazan (VPZ) has demonstrated the capacity to achieve gastric pH levels exceeding 4, comparable to PPIs. This study aims to evaluate the comparative efficacy of intravenous PPI infusion versus VPZ in preventing re-bleeding after endoscopic hemostasis in patients with high-risk peptic ulcers. : A randomized, double-blind, controlled, and double-dummy design was employed. Patients with peptic ulcer bleeding (Forrest class IA/IB or IIA/IIB) who underwent endoscopic hemostasis were randomly assigned to either the PPI group or the VPZ group. Re-bleeding rates at 3, 7, and 30 days, the number of blood transfusions required, length of hospitalization, and ulcer healing rate at 56 days were assessed. A total of 44 eligible patients were enrolled, including 20 patients (PPI group, = 11; VPZ group, = 9) with high-risk peptic ulcers. The mean age was 66 years, with 70% being male. Re-bleeding within 72 h occurred in 9.1% of the PPI group versus 0% in the VPZ group ( = 1.000). There was no significant difference in re-bleeding rates within 7 days and 30 days (18.2% vs. 11.1%, = 1.000). Additionally, the ulcer healing rate did not significantly differ between the groups (87.5% vs. 77.8%). : This pilot study demonstrates comparable efficacy between oral vonoprazan and continuous PPI infusion in preventing recurrent bleeding events among high-risk peptic ulcer patients following successful endoscopic hemostasis.
PubMed: 38930134
DOI: 10.3390/jcm13123606