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Clinical Neuroradiology Jun 2023The introduction of the first whole-body CT scanner in 1974 marked the beginning of cross-sectional spine imaging. In the last decades, the technological advancement,... (Review)
Review
The introduction of the first whole-body CT scanner in 1974 marked the beginning of cross-sectional spine imaging. In the last decades, the technological advancement, increasing availability and clinical success of CT led to a rapidly growing number of CT examinations, also of the spine. After initially being primarily used for trauma evaluation, new indications continued to emerge, such as assessment of vertebral fractures or degenerative spine disease, preoperative and postoperative evaluation, or CT-guided interventions at the spine; however, improvements in patient management and clinical outcomes come along with higher radiation exposure, which increases the risk for secondary malignancies. Therefore, technical developments in CT acquisition and reconstruction must always include efforts to reduce the radiation dose. But how exactly can the dose be reduced? What amount of dose reduction can be achieved without compromising the clinical value of spinal CT examinations and what can be expected from the rising stars in CT technology: artificial intelligence and photon counting CT? In this article, we try to answer these questions by systematically reviewing dose reduction techniques with respect to the major clinical indications of spinal CT. Furthermore, we take a concise look on the dose reduction potential of future developments in CT hardware and software.
Topics: Humans; Artificial Intelligence; Cross-Sectional Studies; Radiation Dosage; Tomography, X-Ray Computed; Spine
PubMed: 36416936
DOI: 10.1007/s00062-022-01227-1 -
Radiation Oncology (London, England) Nov 2022This systematic review aims to synthesise the outcomes of different strategies of incorporating functional biological markers in the radiation therapy plans of patients... (Review)
Review
RATIONALE
This systematic review aims to synthesise the outcomes of different strategies of incorporating functional biological markers in the radiation therapy plans of patients with glioblastoma to support clinicians and further research.
METHODS
The systematic review protocol was registered on PROSPERO (CRD42021221021). A structured search for publications was performed following PRISMA guidelines. Quality assessment was performed using the Newcastle-Ottawa Scale. Study characteristics, intervention methodology and outcomes were extracted using Covidence. Data analysis focused on radiation therapy target volumes, toxicity, dose distributions, recurrence and survival mapped to functional image-guided radiotherapy interventions.
RESULTS
There were 5733 citations screened, with 53 citations (n = 32 studies) meeting review criteria. Studies compared standard radiation therapy planning volumes with functional image-derived volumes (n = 20 studies), treated radiation therapy volumes with recurrences (n = 15 studies), the impact on current standard target delineations (n = 9 studies), treated functional volumes and survival (n = 8 studies), functionally guided dose escalation (n = 8 studies), radiomics (n = 4 studies) and optimal organ at risk sparing (n = 3 studies). The approaches to target outlining and dose escalation were heterogeneous. The analysis indicated an improvement in median overall survival of over two months compared with a historical control group. Simultaneous-integrated-boost dose escalation of 72-76 Gy in 30 fractions appeared to have an acceptable toxicity profile when delivered with inverse planning to a volume smaller than 100 cm[Formula: see text].
CONCLUSION
There was significant heterogeneity between the approaches taken by different study groups when implementing functional image-guided radiotherapy. It is recommended that functional imaging data be incorporated into the gross tumour volume with appropriate technology-specific margins used to create the clinical target volume when designing radiation therapy plans for patients with glioblastoma.
Topics: Humans; Glioblastoma; Radiotherapy Dosage; Radiotherapy, Intensity-Modulated; Radiotherapy Planning, Computer-Assisted; Functional Neuroimaging
PubMed: 36371225
DOI: 10.1186/s13014-022-02146-8 -
Frontiers in Oncology 2022Pain relief is one of the main objectives of radiotherapy for cancer patients with bone metastases. Stereotactic body radiotherapy (SBRT) enables precise delivery of a...
BACKGROUND
Pain relief is one of the main objectives of radiotherapy for cancer patients with bone metastases. Stereotactic body radiotherapy (SBRT) enables precise delivery of a higher dosage to the target area. Several trials have reported comparisons between SBRT and conventional radiotherapy (cRT) in patients with painful bone metastasis. However, the results of those investigations were inconsistent, and no systematic review or meta-analysis has been done till now.
METHODS
We systematically searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), and Clinicaltrials.gov up to May 1, 2022 for relevant studies. Patients with painful bone metastasis who received SBRT or cRT were included. The primary outcome was the patients' pain response rate at three months. The secondary outcomes included the rate of pain responders at one month and six months, oral morphine equivalent dose (OMED) use, and any adverse events. STATA software 12.0 was used for the statistical analysis.
RESULTS
We collected 533 patients' data from 4 randomized controlled trials (RCTs), there was a significant difference of pain response rate at 3 months between two groups (RR = 1.41, 95% CI: 1.12-1.77, = 0.0%, P = 0.003). However, no significant difference was found in pain response rate at 1 month (RR = 1.19, 95% CI: 0.91-1.54, = 31.5%, P = 0.201) and 6 months (RR = 1.25, 95% CI: 0.93-1.69, = 0.0%, P = 0.140). OMED consumption was not significantly different in patients treated with SBRT compared with control group (WMD = -1.11, 95% CI: -17.51-15.28, = 0.0%, P = 0.894). For safety outcome, no statistical difference was found between SBRT and cRT (RR = 0.72, 95% CI: 0.46-1.14, 20.1%, P = 0.162).
CONCLUSION
This study shows that for painful bone metastases, patients with SBRT experienced better pain relief 3 months after radiation than patients with cRT, and SBRT did not increase the incidence of adverse events.
SYSTEMATIC REVIEW REGISTRATION
https://inplasy.com/inplasy-2022-6-0099/, identifier INPLASY202260099.
PubMed: 36338685
DOI: 10.3389/fonc.2022.979201 -
Radiotherapy and Oncology : Journal of... Oct 2022Recently, a number of clinical studies have explored links between possible Relative Biological Effectiveness (RBE) elevations and patient toxicities and/or image... (Review)
Review
Recently, a number of clinical studies have explored links between possible Relative Biological Effectiveness (RBE) elevations and patient toxicities and/or image changes following proton therapy. Our objective was to perform a systematic review of such studies. We applied a "Problem [RBE], Intervention [Protons], Population [Patients], Outcome [Side effect]" search strategy to the PubMed database. From our search, we retrieved studies which: (a) performed novel voxel-wise analyses of patient effects versus physical dose and LET (n = 13), and (b) compared image changes between proton and photon cohorts with regard to proton RBE (n = 9). For each retrieved study, we extracted data regarding: primary tumour type; size of patient cohort; type of image change studied; image-registration method (deformable or rigid); LET calculation method, and statistical methodology. We compared and contrasted their methods in order to discuss the weight of clinical evidence for variable proton RBE. We concluded that clinical evidence for variable proton RBE remains statistically weak at present. Our principal recommendation is that proton centres and clinical trial teams collaborate to standardize follow-up protocols and statistical analysis methods, so that larger patient cohorts can ultimately be considered for RBE analyses.
Topics: Humans; Relative Biological Effectiveness; Proton Therapy; Protons; Linear Energy Transfer; Radiotherapy Planning, Computer-Assisted
PubMed: 35988776
DOI: 10.1016/j.radonc.2022.08.014 -
Medical Physics Sep 2022The use of deep learning (DL) to improve cone-beam CT (CBCT) image quality has gained popularity as computational resources and algorithmic sophistication have advanced... (Review)
Review
The use of deep learning (DL) to improve cone-beam CT (CBCT) image quality has gained popularity as computational resources and algorithmic sophistication have advanced in tandem. CBCT imaging has the potential to facilitate online adaptive radiation therapy (ART) by utilizing up-to-date patient anatomy to modify treatment parameters before irradiation. Poor CBCT image quality has been an impediment to realizing ART due to the increased scatter conditions inherent to cone-beam acquisitions. Given the recent interest in DL applications in radiation oncology, and specifically DL for CBCT correction, we provide a systematic theoretical and literature review for future stakeholders. The review encompasses DL approaches for synthetic CT generation, as well as projection domain methods employed in the CBCT correction literature. We review trends pertaining to publications from January 2018 to April 2022 and condense their major findings-with emphasis on study design and DL techniques. Clinically relevant endpoints relating to image quality and dosimetric accuracy are summarized, highlighting gaps in the literature. Finally, we make recommendations for both clinicians and DL practitioners based on literature trends and the current DL state-of-the-art methods utilized in radiation oncology.
Topics: Cone-Beam Computed Tomography; Deep Learning; Humans; Image Processing, Computer-Assisted; Phantoms, Imaging; Radiometry; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted
PubMed: 35789489
DOI: 10.1002/mp.15840 -
Current Oncology (Toronto, Ont.) May 2022Selective internal radiation therapy (SIRT) with yttrium-90 (Y)-loaded microspheres is increasingly used for the treatment of Intrahepatic Cholangiocarcinoma (ICC).... (Review)
Review
Selective internal radiation therapy (SIRT) with yttrium-90 (Y)-loaded microspheres is increasingly used for the treatment of Intrahepatic Cholangiocarcinoma (ICC). Dosimetry verifications post-treatment are required for a valid assessment of any dose-response relationship. We performed a systematic review of the literature to determine how often clinics conducted post-treatment dosimetry verification to measure the actual radiation doses delivered to the tumor and to the normal liver in patients who underwent SIRT for ICC, and also to explore the corresponding dose-response relationship. We also investigated other factors that potentially affect treatment outcomes, including the type of microspheres used and concomitant chemotherapy. Out of the final 47 studies that entered our study, only four papers included post-treatment dosimetry studies after SIRT to quantitatively assess the radiation doses delivered. No study showed that one microsphere type provided a benefit over another, one study demonstrated better imaging-based response rates associated with the use of glass-based TheraSpheres, and two studies found similar toxicity profiles for different types of microspheres. Gemcitabine and cisplatin were the most common chemotherapeutic drugs for concomitant administration with SIRT. Future studies of SIRT for ICC should include dosimetry to optimize treatment planning and post-treatment radiation dosage measurements in order to reliably predict patient responses and liver toxicity.
Topics: Humans; Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Chemoradiotherapy; Cholangiocarcinoma; Yttrium Radioisotopes
PubMed: 35735415
DOI: 10.3390/curroncol29060306 -
Radiotherapy and Oncology : Journal of... Aug 2022For radiotherapy of thoracic and abdominal tumors safety margins are applied to address geometrical uncertainties caused by e.g. set-up errors, organ motion and... (Review)
Review
For radiotherapy of thoracic and abdominal tumors safety margins are applied to address geometrical uncertainties caused by e.g. set-up errors, organ motion and delineation variability. For pediatric patients no standardized margins are defined. Moreover, studies on these geometrical uncertainties are relatively scarce. Therefore, this systematic review presents an overview of organ motion, applied margin sizes and delineation variability in patients <18 years. A search from January 2000 to March 2021 in Medline, Embase, Web of Science, ClinicalTrials.gov and the International Trials Registry Platform resulted in the inclusion of 117 studies reporting on organ motion, margin sizes and/or delineation variability. Studies were heterogeneous concerning age, tumor types, the use of general anesthesia, imaging modalities; image guidance techniques were reported in 39% of the studies. Inter- and intrafractional motion as reported for different organs was largest in cranio-caudal direction and ranged from -9.1 to 10.0 mm and -4.4 to 19.5 mm, respectively. Motion quantification methodologies differed between studies regarding measures of displacement and definitions of motion direction. Reported CTV-PTV margins varied from 3 to 20 mm for both thoracic and abdominal targets, and for spinal and pelvic from 3to 15 mm and 3 to 10 mm, respectively. Studies reported wide variation in interobserver variability of target volume delineation, which may affect dose distributions to both target volumes and organs at risk. Results of this review indicate possible reduction of margin sizes for children, however, wide variation in organ motion and delineation variability caused by differences in methodologies and outcomes hamper the use of standardized margins.
Topics: Child; Dose Fractionation, Radiation; Humans; Organ Motion; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Image-Guided
PubMed: 35640771
DOI: 10.1016/j.radonc.2022.05.021 -
Clinical and Translational Radiation... Jul 2022Radiotherapy (RT) is a cornerstone treatment strategy for brain tumours. Besides cytotoxicity, RT can cause disruption of the blood-brain barrier (BBB), resulting in an... (Review)
Review
Radiotherapy (RT) is a cornerstone treatment strategy for brain tumours. Besides cytotoxicity, RT can cause disruption of the blood-brain barrier (BBB), resulting in an increased permeability into the surrounding brain parenchyma. Although this effect is generally acknowledged, it remains unclear how and to what extent different radiation schemes affect BBB integrity. The aim of this systematic review and meta-analysis is to investigate the effect of photon RT regimens on BBB permeability, including its reversibility, in clinical and preclinical studies. We systematically reviewed relevant clinical and preclinical literature in PubMed, Embase, and Cochrane search engines. A total of 69 included studies (20 clinical, 49 preclinical) were qualitatively and quantitatively analysed by meta-analysis and evaluated on key determinants of RT-induced BBB permeability in different disease types and RT protocols. Qualitative data synthesis showed that 35% of the included clinical studies reported BBB disruption following RT, whereas 30% were inconclusive. Interestingly, no compelling differences were observed between studies with different calculated biological effective doses based on the fractionation schemes and cumulative doses; however, increased BBB disruption was noted during patient follow-up after treatment. Qualitative analysis of preclinical studies showed RT BBB disruption in 78% of the included studies, which was significantly confirmed by meta-analysis (p < 0.01). Of note, a high risk of bias, publication bias and a high heterogeneity across the studies was observed. This systematic review and meta-analysis sheds light on the impact of RT protocols on BBB integrity and opens the discussion for integrating this factor in the decision-making process of future RT, with better study of its occurrence and influence on concomitant or adjuvant therapies.
PubMed: 35601799
DOI: 10.1016/j.ctro.2022.04.013 -
Radiotherapy and Oncology : Journal of... Jul 2022Lung cancer radiotherapy increases the risk of cardiotoxicity and heart radiation dose is an independent predictor of poor survival. This study describes heart doses and...
BACKGROUND AND PURPOSE
Lung cancer radiotherapy increases the risk of cardiotoxicity and heart radiation dose is an independent predictor of poor survival. This study describes heart doses and strategies aiming to reduce exposure.
MATERIALS AND METHODS
A systematic review of lung cancer dosimetry studies reporting heart doses published 2013-2020 was undertaken. Doses were compared according to laterality, region irradiated, treatment modality (stereotactic ablative body radiotherapy (SABR) and non-SABR), planning technique, and respiratory motion management.
RESULTS
For 392 non-SABR regimens in 105 studies, the average MHD was 10.3 Gy (0.0-48.4) and was not significantly different between left and right-sided tumours. It was similar between IMRT and 3DCRT (10.9 Gy versus 10.6 Gy) and lower with particle beam therapy (proton 7.0 Gy; carbon-ion 1.9 Gy). Active respiratory motion management reduced exposure (7.4 Gy versus 9.3 Gy). For 168 SABR regimens in 35 studies, MHD was 4.0 Gy (0.0-32.4). Exposure was higher in central and lower lobe lesions (6.3 and 5.8 Gy respectively). MHD was lowest for carbon ions (0.5 Gy) compared to other techniques. Active respiratory motion management reduced exposure (2.4 Gy versus 5.0 Gy). Delineation guidelines and Dose Volume Constraints for the heart varied substantially.
CONCLUSIONS
There is scope to reduce heart radiation dose in lung cancer radiotherapy. Consensus on planning objectives, contouring and DVCs for the heart may lead to reduced heart doses in the future. For IMRT, more stringent optimisation objectives may reduce heart dose. Active respiratory motion management or particle therapy may be considered in situations where cardiac dose is high.
Topics: Carbon; Heart; Humans; Lung Neoplasms; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Intensity-Modulated
PubMed: 35577022
DOI: 10.1016/j.radonc.2022.05.007 -
BMJ (Clinical Research Ed.) Mar 2022To compare the efficacy of covid-19 vaccines between immunocompromised and immunocompetent people. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To compare the efficacy of covid-19 vaccines between immunocompromised and immunocompetent people.
DESIGN
Systematic review and meta-analysis.
DATA SOURCES
PubMed, Embase, Central Register of Controlled Trials, COVID-19 Open Research Dataset Challenge (CORD-19), and WHO covid-19 databases for studies published between 1 December 2020 and 5 November 2021. ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform were searched in November 2021 to identify registered but as yet unpublished or ongoing studies.
STUDY SELECTION
Prospective observational studies comparing the efficacy of covid-19 vaccination in immunocompromised and immunocompetent participants.
METHODS
A frequentist random effects meta-analysis was used to separately pool relative and absolute risks of seroconversion after the first and second doses of a covid-19 vaccine. Systematic review without meta-analysis of SARS-CoV-2 antibody titre levels was performed after first, second, and third vaccine doses and the seroconversion rate after a third dose. Risk of bias and certainty of evidence were assessed.
RESULTS
82 studies were included in the meta-analysis. Of these studies, 77 (94%) used mRNA vaccines, 16 (20%) viral vector vaccines, and 4 (5%) inactivated whole virus vaccines. 63 studies were assessed to be at low risk of bias and 19 at moderate risk of bias. After one vaccine dose, seroconversion was about half as likely in patients with haematological cancers (risk ratio 0.40, 95% confidence interval 0.32 to 0.50, I=80%; absolute risk 0.29, 95% confidence interval 0.20 to 0.40, I=89%), immune mediated inflammatory disorders (0.53, 0.39 to 0.71, I=89%; 0.29, 0.11 to 0.58, I=97%), and solid cancers (0.55, 0.46 to 0.65, I=78%; 0.44, 0.36 to 0.53, I=84%) compared with immunocompetent controls, whereas organ transplant recipients were 16 times less likely to seroconvert (0.06, 0.04 to 0.09, I=0%; 0.06, 0.04 to 0.08, I=0%). After a second dose, seroconversion remained least likely in transplant recipients (0.39, 0.32 to 0.46, I=92%; 0.35, 0.26 to 0.46), with only a third achieving seroconversion. Seroconversion was increasingly likely in patients with haematological cancers (0.63, 0.57 to 0.69, I=88%; 0.62, 0.54 to 0.70, I=90%), immune mediated inflammatory disorders (0.75, 0.69 to 0.82, I=92%; 0.77, 0.66 to 0.85, I=93%), and solid cancers (0.90, 0.88 to 0.93, I=51%; 0.89, 0.86 to 0.91, I=49%). Seroconversion was similar between people with HIV and immunocompetent controls (1.00, 0.98 to 1.01, I=0%; 0.97, 0.83 to 1.00, I=89%). Systematic review of 11 studies showed that a third dose of a covid-19 mRNA vaccine was associated with seroconversion among vaccine non-responders with solid cancers, haematological cancers, and immune mediated inflammatory disorders, although response was variable in transplant recipients and inadequately studied in people with HIV and those receiving non-mRNA vaccines.
CONCLUSION
Seroconversion rates after covid-19 vaccination were significantly lower in immunocompromised patients, especially organ transplant recipients. A second dose was associated with consistently improved seroconversion across all patient groups, albeit at a lower magnitude for organ transplant recipients. Targeted interventions for immunocompromised patients, including a third (booster) dose, should be performed.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO CRD42021272088.
Topics: COVID-19; COVID-19 Vaccines; Humans; Immunocompetence; SARS-CoV-2; Seroconversion
PubMed: 35236664
DOI: 10.1136/bmj-2021-068632