CARBON-11 CHOLINE POSITRON EMISSION TOMOGRAPHY-COMPUTED TOMOGRAPHY FOR HYPERPARATHYROIDISM
Primary hyperparathyroidism causes increased production of parathyroid hormone which leads to high calcium levels in the blood. This situation may cause osteoporosis and cardiovascular diseases. Surgery of parathyroid is the most common treatment modality. Before surgery, the patient has to undergo imaging such as ultrasonography of the neck, single-photon emission computed tomography (CT)/CT with I-123 sestamibi, or four-dimensional CT to locate the abnormal parathyroid glands. However, all the above conventional imaging modalities have limitations for accuracy which become more severe in the case of reoperative parathyroidectomy. Researchers at Mayo Clinic, Minnesota, USA, noted the accumulation of C-11 choline, in hyperactive parathyroid cells and thereafter, found that C-11 choline positron emission tomography (PET)/CT could identify the abnormal parathyroid glands in patients who require further treatment after standard imaging but before surgery. These could be those cases, especially where standard imaging has failed to identify the disorder and the patient has undergone unsuccessful initial surgery due to limitations of other imaging modalities. The researchers reviewed the cases of 43 such patients and choline-11 PET/CT found positive findings in 33 (77%) cases. After this, 25 patients underwent surgery and 20 out of 25 (80%) achieved an intraoperative cure. It is to note that 18 out of 25 (72%) had failed prior surgery. In nutshell, C-11 choline PET-CT showed a sensitivity of 64% and a positive predictive value of 72% in a highly selective cohort of negative conventional imaging and failed surgeries. However, the short half-life of 20.4 min of C-11 choline may prove a limitation since it would require its on-site production and administration.
The details may be seen at: https://www.auntminnie.com/index.aspx?sec = sup&sub = mol&pag = dis&ItemID = 138235.
CERIUM OXIDE NANO PARTICLES MAY PROTECT BONE DURING RADIOTHERAPY
Radiotherapy, though directed to the cancer tumor, does affect the surrounding normal tissues including bone. Bone damage during radiotherapy may occur in about 75% of patients. Researchers from University of Central Florida, US, in collaboration with researchers from Oakland University, North Carolina A and T University, the University of Sheffield, and University of Huddersfield have designed an artificial enzyme consisted of cerium oxide nanoparticles which acts like antioxidants. Our body produces natural antioxidants but this mechanism gets overwhelmed in face of radiation exposure. The artificially created antioxidant adds in the defense mechanism of the body against cell damage. It has been seen that cerium oxide nanoparticles also help in killing cancer cells possibly by increasing acidity and save the loss of red blood cells (RBCs) and white blood cells (WBCs). It helps the patient since lower counts of RBC and WBC make the patient more prone to catch opportunistic infection, less able to fight cancer and leave them exhausted (fatigued). On the other hand, nanoparticles were found to help healthy cells to produce more antioxidants, reduce inflammation, and help in bone growth. Researchers are now focusing to find the mechanism of the help these nanoparticles extend in killing cancer cells. Their focus will be the patients of breast cancer who are more prone to bone damage than men.
The details may be seen at: https://beta.nsf.gov/news/researchers-design-treatment-protect-bones-during?utm_medium = email&utm_source = govdelivery.
PHOTON-COUNTING COMPUTED TOMOGRAPHY MAY QUANTIFY LEVER FAT
Hepatic steatosis is a medical condition which indicates the increased build-up of fat in the liver. Obesity, type 2 diabetes, and sometimes excessive consumption of alcohol are the risk factors for hepatic steatosis. Hepatic steatosis may lead to liver cirrhosis in 20% of patients, and magnetic resonance imaging (MRI) is a typical imaging modality for its diagnosis. However, CT is an economical and more common imaging modality than MRI and hence the researchers at Duke University, North Carolina, US, investigated the capability of photon-counting CT (PCCT) for quantification of liver fat in obese patients and found that it may match the results with that of MRI. This way the PCCT may be used for opportunistic screening for fatty liver disease. The researchers compared the results using phantoms with inserts with varying degrees of concentrations of fat (from 0% to 100%) and fat iodine mixtures (fat 0%–50% and iodine 3 mg/ml). The phantoms were imaged in PCCT and a 1.5 T MRI. There was no significant difference between the MRI measured concentration of fat and that measured by PCCT (P = 0.32). The same was the case for iodine concentration (P = 0.6). After this, the researchers scanned 12 obese patients with fatty liver disease in MRI and PCCT but there was no significant difference in mean signal fat fraction (P = 0.138, 14.5% in MRI vs. 11.8% in PCCT).
The details may be seen at: https://www.auntminnie.com/index. aspx?sec = sup&sub = mri&pag = dis&ItemID = 139021.
PHOTON-COUNTING COMPUTED TOMOGRAPHY FOR THE DIAGNOSIS OF PULMONARY EMBOLISM
Acute pulmonary embolism (PE) is a lethal condition and patients with suspected PE are often presented with dyspnea. Timely diagnosis and treatment are important for a positive outcome. Researchers from University Hospital of Wurzburg (Uniklinikum Wurzburg), Germany, used PCCT in PE to find the spectral information from high-pitch PE. Traditionally, energy-integrating dual-energy CT pulmonary angiography (CTPA) is the choice of imaging modality. The researchers compared the subjective and objective image quality along with contrast and radiation dose for the diagnosis of PE in the case of PCCT and conventional dual-energy CT. Thirty-two PCCT CTPA examinations used 25 ml of contrast and delivered 2.5 Gy. cm CT dose index-volume (CTDIvol) while 32 conventional CT used 50 ml of contrast and delivered 5.1 Gy.cm CTDIvol. Four image readers compared pulmonary artery CT attenuation, signal-to-noise ratio (SNR), contrast-to-noise ratio, and subjective image quality in two images. It was noted that while the first three objective criteria were significantly higher in the case of conventional CT but the readers rated subjective image quality of 60 keV PCCT scan as excellent or good in 94.4% of images (as compared to 84.4% in conventional CT). The researchers conclude that in PCCT, we may use a half dose of contrast medium with half radiation dose while maintain the image quality from good to excellent in almost all cases.
The details may be seen at: https://www.auntminnie.com/index.aspx?sec = sup&sub = cto&pag = dis&itemId = 139018.
CARBON QUANTUM DOTS IMPROVES CHERENKOV IMAGING DURING RADIATION TREATMENT
When the charged particles travel at a speed greater than the phase velocity of light in the tissue, the Cherenkov light is produced. During radiation treatment of cancer with Mega Volt (MV) X-ray, the production of Cherenkov light provides an opportunity to visualize the radiation beam in real time on a patient’s body and hence may indicate the exact location of radiation delivery and the radiation dose. The Cherenkov emission is proportional to the radiation dose delivered and has high spatial resolution and fast imaging speed as compared to the traditional method of the measurement of radiation dose. However, the intensity of Cherenkov light is very low and is scattered and absorbed by the tissues. Conventional Charge Coupled Device (CCD) cameras have their limits in collecting these low Cherenkov signals and hence may need costly complementary metal–oxide–semiconductor-CCD cameras. Researchers from Nanjing University of Aeronautics and Astronautics, China, have improved the quality of Cherenkov imaging by incorporating a flexible but nontoxic sheet of carbon quantum dots (cQDs) attached to the patient. cQDs have absorption spectra in the energy range of Cherenkov light and hence they absorb it and emit luminescence at higher energy range which falls in the sensitive range of the CCD camera and hence increasing the overall sensitivity of the Cherenkov imaging system. Cherenkov photons are generated in the superficial surface of the tissue and some of them generate fluorescence. Some fluorescence gets converted into radio-luminescence generated by cQDs. Thus, the final optical output is composed of all of the above leading to increased SNR and image quality. The 10 mm dia cQDs with ultraviolet (UV)-curable adhesive is spin coated on the substrate coated with plastic sheet and then solidified with UV exposure. Plastic coating ensures that scintillation material does not come in the contact with the skin. The flexible cQD sheet is transparent to the Cherenkov emission with a thickness of 222 ± 5 mm and diameter of 15 cm and it conforms to the contour of the body surface. For testing, the solid water phantom was covered with 2-mm layer of skin-toned clay to simulate the optical properties of the skin. The researchers conducted the experiment by delivering radiation doses from 100 to 500 MU using 6 and 10 MV X-ray photons for varied cQD concentrations of no concentration (zero), 0.05, and 0.1 mg/ml and measured the intensity of Cherenkov signal in these combinations. Application of the cQD sheet doubled the SNR in solid water phantom. After this, they used cQD sheet to bolus, mask, and the combination of bolus and mask on an anthropomorphic phantom and found increased optical intensity with over 60% increase in SNR in all cases. Further research is going on in using cQD sheeting in pinpointing the area of electron therapy of keloids, a benign fibrous lesion which is an over-healing process. Electron beam irradiation may reduce the rate of recurrence after the surgery of keloids but insufficient or excessive dose at the mismatched adjacent fields may cause tissue damage leading to the recurrence of keloids. cQD sheet may improve the delivery of electron beam to keloid and the matching of radiation areas.
The details may be seen at: https://physicsworld.com/a/a-sheet-of-quantum-dots-enhances-cherenkov-imaging-of-radiotherapy-dose/?utm_medium = email&utm_source = iop&utm_term=&utm_campaign = 14258-54586&utm_content = Title%3A%20A%20sheet%20of%20quantum%20dots%20enhances%20Cherenkov%20imaging%20of%20radiotherapy%20dose%20-%20research_updates&Campaign + Owner=.
PATIENT POSITION CHAIR FOR UPRIGHT RADIATION TREATMENT
An upright patient positioning chair has been developed by Leo Cancer Care which was originally founded in Australia. Typically, radiation for cancer treatment is delivered to the patient in a supine lying position. However, for some malignancies such as thoracic, pelvic, and head-and-neck cancer, the upright position of the body may improve the accuracy in radiation delivery leading to better outcomes by increasing the exposure to tumor, reducing the dose to nearby organ-at-risks, and making the breath-hold easier for some patients. The upright chair has seat, backrest, arm support, shin rest, and a heel stop and all these may be adjusted to various positions and angles. The chair may rotate (one rotation in a minute) and may move vertically up to 70 cm simultaneously and thus it may create helical or spiral movement. The chair includes up to five high-resolution cameras for the optical guide and track system. The chair is equipped with vacuum cushion which may immobilize the patient by taking the shape and size of the individual patient. There is also a belt on the upper part of the abdomen. The chair has capability to place the patient in an appropriate posture according to the cancer type being treated. For example, patients sit vertically for head-and-neck treatment, they sit leaning slightly backward for lung and liver radiotherapy while they are seated slightly leaned forward for breast treatment. For pelvic and prostrate treatment, the patient is perched on the chair and gets support to the back of the thigh and knee rest. Researchers have evaluated the upright chair at Centre Leon Berard, France, for the accuracy of immobilization, the time required for set-up, and the level of comfort for 16 patients undergoing radiation treatment of prostate, bladder, rectum, endometrium, cervix, etc., which may be grouped as pelvic cancers. Two radiotherapy technologists working on patent set-up initially took 4–6 min for set-up which improved later to 2–5 min. The error in inter-fraction repositioning was <1 mm and the intra-fraction motion over 20 min was found to be 3 mm. Most of the patients felt the upright position was good and some of them mentioned it was better than the supine position. The researchers investigated the accuracy of the upright chair by scheduling three additional measurements by repositioning to know the accuracy. Image registration could be performed using skin surface and without any skin marks, tattoos, or landmarks. Inter-fraction shift of −0.5 mm, −0.4 mm, and −0.9 mm was noted in the x, y, and z directions, respectively. Intra-fraction motion was checked every 4 min during the movement of the chair. After 20 min, the mean intra-fraction shifts were 0 in the x and z direction and 0.2 mm in the y direction. Inter-fraction shifts by more than 3 mm and intra-fraction shifts by more than 2 mm were only in 10% of patients in an upright chair. Further optimization of the design of the belt and backrest is on the anvil after the feedback of the patients and researchers.
The details may be seen at: https://physicsworld.com/a/patient-positioning-chair-paves-the-way-for-upright-radiotherapy/?Campaign + Owner=&utm_campaign=14258-54633&utm_content = Title%3A%20Patient%20positioning%20chair%20paves%20the%20way%20for%20upright%20radiotherapy%20-%20research_updates&utm_term=&utm_medium=email&utm_source=iop.
