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Generation of fluoroscopy-alike radiographs as alternative datasets for deep learning in interventional radiology

Fum WKS, Md Shah MN, Raja Aman RRA, Abd Kadir KA, Wen DW, Leong S, et al.

Phys Eng Sci Med, 2023 Dec;46(4):1535-1552.
PMID: 37695509 DOI: 10.1007/s13246-023-01317-5

In fluoroscopy-guided interventions (FGIs), obtaining large quantities of labelled data for deep learning (DL) can be difficult. Synthetic labelled data can serve as an alternative, generated via pseudo 2D projections of CT volumetric data. However, contrasted vessels have low visibility in simple 2D projections of contrasted CT data. To overcome this, we propose an alternative method to generate fluoroscopy-like radiographs from contrasted head CT Angiography (CTA) volumetric data. The technique involves segmentation of brain tissue, bone, and contrasted vessels from CTA volumetric data, followed by an algorithm to adjust HU values, and finally, a standard ray-based projection is applied to generate the 2D image. The resulting synthetic images were compared to clinical fluoroscopy images for perceptual similarity and subject contrast measurements. Good perceptual similarity was demonstrated on vessel-enhanced synthetic images as compared to the clinical fluoroscopic images. Statistical tests of equivalence show that enhanced synthetic and clinical images have statistically equivalent mean subject contrast within 25% bounds. Furthermore, validation experiments confirmed that the proposed method for generating synthetic images improved the performance of DL models in certain regression tasks, such as localizing anatomical landmarks in clinical fluoroscopy images. Through enhanced pseudo 2D projection of CTA volume data, synthetic images with similar features to real clinical fluoroscopic images can be generated. The use of synthetic images as an alternative source for DL datasets represents a potential solution to the application of DL in FGIs procedures.

Matched MeSH terms: Fluoroscopy/methods
Assessment of patient and occupational exposure and radiation risk from cath-lab procedure

Sulieman A, Mahgoub O, Salah H, Tamam N, Taha A, Dawood S, et al.

Appl Radiat Isot, 2023 Dec;202:111071.
PMID: 37871398 DOI: 10.1016/j.apradiso.2023.111071

Due to the extended localized fluoroscopy, many radiographic exposures, and multiple procedures that might result in tissue reaction, patients and personnel received a significant radiation dose during interventional cardiology (IR) procedures. This study aims to calculate the radiation risk and assess patient and staff effective doses during IC procedures. Thirty-two patients underwent a Cath lab treatment in total. Ten Cath lab personnel, including six nurses, two cardiologists, and two X-ray technologists. Optical stimulating-luminescent dosimeters (OSL) (Al2O3:C) calibrated for this purpose were used to monitor both occupational and ambient doses. Using an automated OSL reader, these badges were scanned. The Air Kerma (mGy) and Kerma Area Products (KAP, mGy.cm2) have a mean and standard deviation (SD) of 371 ± 132 and 26052, respectively. The average personal dose equivalent (mSv) and its range for cardiologists, nurses and X ray technologists were 1.11 ± 0.21 (0.96-1.26), 0.84 ± 0.11 (0.68-1.16), and 0.68 ± 0.014 (0.12-0.13), respectively. The current study findings showed that the annual effective dose for cardiologists, nurses, and X-ray technologists was lesser than the yearly occupational dose limit of 20 mSv recommended by national and international guidelines. The patients' doses are comparable with some previously published studies and below the tissue reaction limits.

Matched MeSH terms: Fluoroscopy/methods
A simple technique of intra-uterine transfusion of foetus in University Hospital, Kuala Lumpur

Kwi NK, Hing NK

Med J Malaysia, 1974 Jun;28(4):287-9.
PMID: 4278824
Matched MeSH terms: Fluoroscopy/methods
Real-time eye lens dose monitoring during cerebral angiography procedures

Safari MJ, Wong JH, Kadir KA, Thorpe NK, Cutajar DL, Petasecca M, et al.

Eur Radiol, 2016 Jan;26(1):79-86.
PMID: 26002131 DOI: 10.1007/s00330-015-3818-9

OBJECTIVES: To develop a real-time dose-monitoring system to measure the patient's eye lens dose during neuro-interventional procedures.
METHODS: Radiation dose received at left outer canthus (LOC) and left eyelid (LE) were measured using Metal-Oxide-Semiconductor Field-Effect Transistor dosimeters on 35 patients who underwent diagnostic or cerebral embolization procedures.
RESULTS: The radiation dose received at the LOC region was significantly higher than the dose received by the LE. The maximum eye lens dose of 1492 mGy was measured at LOC region for an AVM case, followed by 907 mGy for an aneurysm case and 665 mGy for a diagnostic angiography procedure. Strong correlations (shown as R(2)) were observed between kerma-area-product and measured eye doses (LOC: 0.78, LE: 0.68). Lateral and frontal air-kerma showed strong correlations with measured dose at LOC (AKL: 0.93, AKF: 0.78) and a weak correlation with measured dose at LE. A moderate correlation was observed between fluoroscopic time and dose measured at LE and LOC regions.
CONCLUSIONS: The MOSkin dose-monitoring system represents a new tool enabling real-time monitoring of eye lens dose during neuro-interventional procedures. This system can provide interventionalists with information needed to adjust the clinical procedure to control the patient's dose.
KEY POINTS: Real-time patient dose monitoring helps interventionalists to monitor doses. Strong correlation was observed between kerma-area-product and measured eye doses. Radiation dose at left outer canthus was higher than at left eyelid.

Matched MeSH terms: Fluoroscopy/methods
Characterization of a MOSkin detector for in vivo skin dose measurements during interventional radiology procedures

Safari MJ, Wong JH, Ng KH, Jong WL, Cutajar DL, Rosenfeld AB

Med Phys, 2015 May;42(5):2550-8.
PMID: 25979047 DOI: 10.1118/1.4918576

The MOSkin is a MOSFET detector designed especially for skin dose measurements. This detector has been characterized for various factors affecting its response for megavoltage photon beams and has been used for patient dose measurements during radiotherapy procedures. However, the characteristics of this detector in kilovoltage photon beams and low dose ranges have not been studied. The purpose of this study was to characterize the MOSkin detector to determine its suitability for in vivo entrance skin dose measurements during interventional radiology procedures.

Matched MeSH terms: Fluoroscopy/methods
ASSESSMENT ON THE INTERCHANGEABILITY OF PERSONAL EFFECTIVE DOSE ALGORITHMS IN FLUOROSCOPY-GUIDED INTERVENTIONS USING BLAND-ALTMAN ANALYSIS

Bohari A, Hashim S, Ghoshal SK, Mohd Mustafa SN

Radiat Prot Dosimetry, 2019 Dec 31;186(4):462-468.
PMID: 31329977 DOI: 10.1093/rpd/ncz051

Long exposure to radiation from fluoroscopy-guided interventions (FGIs) can be detrimental to both patients and radiologists. The effective doses received by the interventional radiology staff after performing 230 FGIs in a year were assessed by using double dosimetry and five various algorithms. The Shapiro-Wilk test revealed normally-distributed data (p < 0.01), while the significant correlation coefficients between the effective doses ranged between 0.88 and 1.00. As for the Bland-Altman analysis, both Niklason and Boetticher algorithms strongly supported the absence of statistical significance between the estimated effective doses. This portrays that the occupational doses received by the interventional radiology staff during FGIs fall within the acceptable limit regardless of the varied algorithms applied. In short, the Niklason and Boetticher algorithms appeared to be the more interchangeable ones for effective evaluation of doses. This is in view of their strong mutual correlations and excellent agreement.

Matched MeSH terms: Fluoroscopy/methods*
Influence of exposure and geometric parameters on absorbed doses associated with common neuro-interventional procedures

Safari MJ, Wong JHD, Jong WL, Thorpe N, Cutajar D, Rosenfeld A, et al.

Phys Med, 2017 Mar;35:66-72.
PMID: 28256398 DOI: 10.1016/j.ejmp.2017.02.002

PURPOSE: The purpose of this study was to investigate the effects of routine exposure parameters on patient's dose during neuro-interventional radiology procedures.
METHODS: We scrutinized the routine radiological exposure parameters during 58 clinical neuro-interventional procedures such as, exposure direction, magnification, frame rate, and distance between image receptor to patient's body and evaluate their effects on patient's dose using an anthropomorphic phantom. Radiation dose received by the occipital region, ears and eyes of the phantom were measured using MOSkin detectors.
RESULTS: DSA imaging technique is a major contributor to patient's dose (80.9%) even though they are used sparingly (5.3% of total frame number). The occipital region of the brain received high dose largely from the frontal tube constantly placed under couch (73.7% of the total KAP). When rotating the frontal tube away from under the couch, the radiation dose to the occipital reduced by 40%. The use of magnification modes could increase radiation dose by 94%. Changing the image receptor to the phantom surface distance from 10 to 40cm doubled the radiation dose received by the patient's skin at the occipital region.
CONCLUSION: Our findings provided important insights into the contribution of selected fluoroscopic exposure parameters and their impact on patient's dose during neuro-interventional radiology procedures. This study showed that the DSA imaging technique contributed to the highest patient's dose and judicial use of exposure parameters might assist interventional radiologists in effective skin and eye lens dose reduction for patients undergoing neuro-interventional procedures.

Matched MeSH terms: Fluoroscopy/methods
Comparison between percutaneous fluoroscopic-guided and conventional open pedicle screw placement techniques for the thoracic spine: a safety evaluation in human cadavers

Kwan MK, Chiu CK, Lee CK, Chan CY

Bone Joint J, 2015 Nov;97-B(11):1555-61.
PMID: 26530660 DOI: 10.1302/0301-620X.97B11.35789

Percutaneous placement of pedicle screws is a well-established technique, however, no studies have compared percutaneous and open placement of screws in the thoracic spine. The aim of this cadaveric study was to compare the accuracy and safety of these techniques at the thoracic spinal level. A total of 288 screws were inserted in 16 (eight cadavers, 144 screws in percutaneous and eight cadavers, 144 screws in open). Pedicle perforations and fractures were documented subsequent to wide laminectomy followed by skeletalisation of the vertebrae. The perforations were classified as grade 0: no perforation, grade 1: < 2 mm perforation, grade 2: 2 mm to 4 mm perforation and grade 3: > 4 mm perforation. In the percutaneous group, the perforation rate was 11.1% with 15 (10.4%) grade 1 and one (0.7%) grade 2 perforations. In the open group, the perforation rate was 8.3% (12 screws) and all were grade 1. This difference was not significant (p = 0.45). There were 19 (13.2%) pedicle fractures in the percutaneous group and 21 (14.6%) in the open group (p = 0.73). In summary, the safety of percutaneous fluoroscopy-guided pedicle screw placement in the thoracic spine between T4 and T12 is similar to that of the conventional open technique.

Matched MeSH terms: Fluoroscopy/methods
Patient Exposure during Fluoroscopy-guided Pacemaker Implantation Procedures

Alkhorayef M, Sulieman A, Babikir E, Daar E, Alnaaimi M, Alduaij M, et al.

Appl Radiat Isot, 2018 Aug;138:14-17.
PMID: 28830729 DOI: 10.1016/j.apradiso.2017.08.010

A pacemaker, which is used for heart resynchronization with electrical impulses, is used to manage many clinical conditions. Recently, the frequency of pacemaker implantation procedures has increased to more than 50% worldwide. During this procedure, patients can be exposed to excessive radiation exposure. Wide range of doses has been reported in previous studies, suggesting that optimization of this procedure has not been fulfilled yet. The current study evaluated patient radiation exposure during cardiac pacemaker procedures and quantified the patient effective dose. A total of 145 procedures were performed for five pacemaker procedures (VVI, VVIR, VVD, VVDR, and DDDR) at two hospitals. Patient doses were measured using the kerma-area product meter. Effective doses were estimated using software based on Monte Carlo simulation from the National Radiological Protection Board (NRPB, now The Health Protection Agency). The effective dose values were used to estimate cancer risk from the pacemaker procedure. Patient demographic data and exposure parameters for fluoroscopy and radiography were quantified. The mean patient doses ± SD per procedure (Gycm2) for VVI, VVIR, VVD, VVDR, and DDDR were 1.52 ± 0.13 (1.43-1.61), 3.28 ± 2.34 (0.29-8.73), 3.04 ± 1.67 (1.57-4.86), 6.04 ± 2.326 3.29-8.58), and 8.8 ± 3.6 (4.5-26.20), respectively. The overall patient effective dose was 1.1mSv per procedure. It is obvious that the DDDR procedure exposed patients to the highest radiation dose. Patient dose variation can be attributed to procedure type, exposure parameter settings, and fluoroscopy time. The results of this study showed that patient doses during different pacemaker procedures are lower compared to previous reported values. Patient risk from pacemaker procedure is low, compared to other cardiac interventional procedures. Patients' exposures were mainly influenced by the type of procedures and the clinical indication.

Matched MeSH terms: Fluoroscopy/methods*