High CT doses return to the agenda

Rühm, W.; Harrison, R. M.

doi:10.1007/s00411-019-00827-9

Cited by 18 publications

(8 citation statements)

References 32 publications

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“…Daily imaging required for adaptive treatments is associated with significant imaging doses and may compromise one of proton therapy aims to minimize the dose to healthy tissue. Moreover, there are general concerns about the overuse of computed tomography (CT) [ 12 , 13 ]. Cone-beam CT (CBCT) also leads to high extra doses, which are comparable to fan-beam CT or might be even higher [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Low-Dose Computed Tomography Scanning Protocols for Online Adaptive Proton Therapy of Head-and-Neck Cancers

Nesteruk

Bobić

Sharp

et al. 2022

Cancers

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Purpose: To evaluate the suitability of low-dose CT protocols for online plan adaptation of head-and-neck patients. Methods: We acquired CT scans of a head phantom with protocols corresponding to CT dose index volume CTDIvol in the range of 4.2–165.9 mGy. The highest value corresponds to the standard protocol used for CT simulations of 10 head-and-neck patients included in the study. The minimum value corresponds to the lowest achievable tube current of the GE Discovery RT scanner used for the study. For each patient and each low-dose protocol, the noise relative to the standard protocol, derived from phantom images, was applied to a virtual CT (vCT). The vCT was obtained from a daily CBCT scan corresponding to the fraction with the largest anatomical changes. We ran an established adaptive workflow twice for each low-dose protocol using a high-quality daily vCT and the corresponding low-dose synthetic vCT. For a relative comparison of the adaptation efficacy, two adapted plans were recalculated in the high-quality vCT and evaluated with the contours obtained through deformable registration of the planning CT. We also evaluated the accuracy of dose calculation in low-dose CT volumes using the standard CT protocol as reference. Results: The maximum differences in D98 between low-dose protocols and the standard protocol for the high-risk and low-risk CTV were found to be 0.6% and 0.3%, respectively. The difference in OAR sparing was up to 3%. The Dice similarity coefficient between propagated contours obtained with low-dose and standard protocols was above 0.982. The mean 2%/2 mm gamma pass rate for the lowest-dose image, using the standard protocol as reference, was found to be 99.99%. Conclusion: The differences between low-dose protocols and the standard scanning protocol were marginal. Thus, low-dose CT protocols are suitable for online adaptive proton therapy of head-and-neck cancers. As such, considering scanning protocols used in our clinic, the imaging dose associated with online adaption of head-and-neck cancers treated with protons can be reduced by a factor of 40.

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Section: Introductionmentioning

confidence: 99%

Low-Dose Computed Tomography Scanning Protocols for Online Adaptive Proton Therapy of Head-and-Neck Cancers

Nesteruk

Bobić

Sharp

et al. 2022

Cancers

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“…Despite the beneficial effects, the ethical concerns to use LDRT in the management of COVID-19 were the risk of spread of infection, time frame for a patient, and inconvenience in treating an intubated patient[ 64 ]. Even though medical imaging is widely used, divergent thoughts existed on the health effects of low-dose IR in scientific communities/stakeholders[ 65 , 66 ]. An “enhanced risk of stochastic effects due to radiation dose received by the patients during CT imaging” and “clarifications” from professional associations and regulatory authorities during this COVID-19 pandemic raised the anxiety among the public at the national level[ 67 , 68 ].…”

Section: Limitations/ Future Improvements On Using X-rays For the Dia...mentioning

confidence: 99%

Impact of X-radiation in the management of COVID-19 disease

Mohan¹,

Nandhini²,

Raavi³

et al. 2022

WJR

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Coronaviruses are a diverse group of viruses that infect both animals and humans. Even though the existence of coronavirus and its infection to humans is not new, the 2019-novel coronavirus (nCoV) caused a major burden to individuals and society i.e. , anxiety, fear of infection, extreme competition for hospitalization, and more importantly financial liability. The nCoV infection/disease diagnosis was based on non-specific signs and symptoms, biochemical parameters, detection of the virus using reverse-transcription polymerase chain reaction (RT-PCR), and X-ray-based imaging. This review focuses on the consolidation of potentials of X-ray-based imaging modality [chest-X radiography (CXR) and chest computed tomography (CT)] and low-dose radiation therapy (LDRT) for screening, severity, and management of COVID-19 disease. Reported studies suggest that CXR contributed significantly toward initial rapid screening/diagnosis and CT- imaging to monitor the disease severity. The chest CT has high sensitivity up to 98% and low specificity for diagnosis and severity of COVID-19 disease compared to RT-PCR. Similarly, LDRT compliments drug therapy in the early recovery/Less hospital stays by maintaining the physiological parameters better than the drug therapy alone. All the results undoubtedly demonstrated the evidence that X-ray-based technology continues to evolve and play a significant role in human health care even during the pandemic.

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“…32 The combined dose from radiotherapy and associated imaging is another major contributor to cumulative patient radiation dose. 82 Nearly half of Canadians are expected to receive a cancer diagnosis, 83 and approximately 50% will be treated with radiotherapy. 82 This indicates that the population of Canadians exposed to high target doses may be significant, 82 and strategies to monitor cumulative radiation dose are warranted.…”

Section: Appropriate Imaging and Radiation Safetymentioning

confidence: 99%

“…82 Nearly half of Canadians are expected to receive a cancer diagnosis, 83 and approximately 50% will be treated with radiotherapy. 82 This indicates that the population of Canadians exposed to high target doses may be significant, 82 and strategies to monitor cumulative radiation dose are warranted. 84 Our survey indicates that 84% of facilities have a process in place for determining the appropriateness of imaging exams, an important means of reducing unnecessary exposure to radiation as part of diagnostic imaging.…”

Section: Appropriate Imaging and Radiation Safetymentioning

confidence: 99%

Canadian Medical Imaging Inventory, 2019–2020

Chao¹,

Sinclair²,

Morrison³

et al. 2021

cjht

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Context and Policy Issues The purpose of the CMII is to document current practices and developments in the supply, distribution, technical operations, and general clinical use of advanced imaging equipment across Canada. Medical imaging is a vital component of modern health care, playing a role in the diagnosis, staging, and monitoring of many diseases and conditions. As new medical imaging technologies become available and population needs change, it is important to keep track of where imaging capacity exists, how equipment is used, and the adoption of tools that may support appropriate imaging, system efficiencies, and wait-list reductions. Methods CADTH collected data on six advanced imaging modalities: CT, MRI, PET-CT, single-photon emission computed tomography (SPECT), SPECT-CT, and PET-MRI using a web-based survey and a search of the literature. The data were reviewed by validators for accuracy and validators provided additional information of provincial and regional policies and practices. Summary of Evidence Of the modalities surveyed, CT is the most widely distributed, with the highest number of units, followed by MRI. All provinces and territories have at least one CT unit; all provinces and Yukon have at least one MRI unit; and all provinces have at least one SPECT and/or SPECT-CT unit. None of the territories have SPECT or SPECT-CT. Nine provinces have PET-CT in clinical use. Two provinces, Alberta and Ontario, have PET-MRI that is used for research purposes. Regarding the total volume of exams, CT is the most-used modality (5.41 million exams per year), followed by MRI (2.33 million exams per year), SPECT and SPECT-CT combined (1.2 million exams per year), and PET-CT (125,775 exams per year). Each imaging modality, apart from SPECT, experienced growth in the last decade in Canada in the number of units and the number of units per million people. CT experienced the slowest growth rate of all imaging modalities — at a 1.4% increase in units per million people over the last decade — compared with other imaging modalities (MRI 20%; PET-CT 25%; and SPECT-CT 70%). Over the last decade, the overall volume of exams increased by 32% and 62% for CT and MRI, respectively. Similarly, the number of exams per thousand population increased by 18% and 46%, respectively. Examination data for the other modalities were not available in 2010. Conclusions and Implications for Decision or Policy-Making The CMII data provides insight into the current context of medical imaging across Canada and raise questions related to how medical imaging is monitored and regulated, and how it is optimally used. As well, the data raise questions about how funding structures are organized, what the most cost-effective practices are, and whether access is equitable, especially in rural and remote areas. Overall, the findings of this report may help decision-makers identify gaps in service; inform medical imaging-related strategic planning on a national, provincial, or territorial basis; and help anticipate future growth and need for replacement. Additionally, the data can be used to identify system efficiencies and monitor the adoption of practices and tools that may support appropriate imaging and wait-list reductions.

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High CT doses return to the agenda

Cited by 18 publications

References 32 publications

Low-Dose Computed Tomography Scanning Protocols for Online Adaptive Proton Therapy of Head-and-Neck Cancers

Low-Dose Computed Tomography Scanning Protocols for Online Adaptive Proton Therapy of Head-and-Neck Cancers

Impact of X-radiation in the management of COVID-19 disease

Canadian Medical Imaging Inventory, 2019–2020

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