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Posts Tagged ‘PET’

Fine localization of 124I-huA33 in colorectal cancer, with no considerable toxicity has been found;

PET-deduced 124I concentrations demonstrated good agreement with other samples, and confirmed quantitative precision of 124I-huA33 PET.

 

The medical research was contributed by Jorge A. Carrasquillo and associates from various departments of Memorial Sloan-Kettering Cancer Center, New York. (Courtesy: The Journal of Nuclear Medicine)

Humanized A33 (huA33) is a monoclonal antibody that is present in normal bowel and above 95% of colorectal cancers. The research team tried PET to assess 124I huA33 focusing bio-distribution, and security in patients with colorectal cancer. They even decided the bio-distribution of 124I-huA33, when higher dose of human intravenous IgG (IVIG) was administered to control the Fc receptor, or when 124I-huA33 was administered through hepatic arterial infusion (HAI).

About 25 patients with primary/metastatic colorectal cancer encompassed the study; 19 had resection. Patients received a median of 343 MBq and 10 mg of 124I-humanized A33.

19 had intravenous antibody administration, 6 through hepatic arterial infusion; 5 received human intravenous IgG.

About 11 patients showed up with 10 primary tumors (vide: Oncology); median concentration (primary colon tumors) was 0.016% instilled dose/gram, in comparison with normal colon that had 0.004%.

Notable uptake in bowel hampered tumor recognition in some patients; patients receiving human intravenous IgG had a considerably shorter serum half-time (corroborated through, Pharmacokinetics).

No deviation could be established in clearance rates amid following groups – IVIG, HAI, intravenous; same was that for maximum serum concentration/volume of distribution, serum region under the curve.

Weak concentration of human–antihuman antibodies were found in 6 patients; no considerable toxicities/side effects were related with huA33.

Conclusion: Good determination/localization of 124I-huA33 in colorectal cancer, with no considerable perniciousness has been found. PET-deduced 124I concentrations showed good agreement with other samples, and confirmed quantitative precision of 124I-huA33 PET; no clinically vital changes in blood clearance were brought about by human intravenous IgG.

The latest Texas MD Anderson Cancer Center research reveal that,PEM scanners with high-resolution breast PET systems are able to assess early Neoadjuvant Chemotherapy signs. The research work was produced at the American Association of Cancer Research Annual Meeting in Washington, DC, by the University of Texas MD Anderson Cancer Center.

Positron Emission Mammography ( PEM ) scanners containing high-resolution breast PET systems, are capable of identifying the location and the metabolic phase of a lesion. The report is cruicial in evaluating a lesion’s malignancy and its effect on the process of patient care. Unfortunately, Mammography and ultrasound imaging systems are only confined to projection of their location and not the metabolic phase.

Dr. Wei Yang, Associate Professor of Radiology at the University of Texas MD Anderson Cancer Center in Houston and her team of researchers discovered that, PEM or Positron Emission Mammography capacitates medical practitioners to detect a patient’s reaction to neoadjuvant medical therapy, at an early stage. Neoadjuvant Chemotherapy is commonly a cancer treatment where the patient is medicated with a drug for the reduction of the size of a tumor before the surgery is conducted.

9 patients with HER2 over-expressing Inflammatory Breast Cancer (IBC) in a Phase II neoadjuvant trial of lapatinib were absorbed in the study over a period of 14 days with chemotherapy following suit. Baseline tumor measurements on mammography, sonography, PEM and PET/CT scans with serial biopsies were taken. The PEM and biopsies were again conducted on the 14 the day. Standardized uptake value (SUV) and Quantification of tumor activity known as PEM uptake value (PUV) were compared for PET/CT pre- and post-lapatinib and correlated with tumor size and proliferation marker Ki67.

The outcome of the study said, critical early recede in PUV as a functional reaction to targeted therapy makes PEM as an early evaluator of patient response of the Neoadjuvant Cancer treatment therapy. Look forward to further peer-reviews as and when the surgical results of the patients are published.

“The high spatial resolution of PEM combined with functional quantification tools has the potential to assess tumor response early in the course of treatment,” said Dr. Yang, lead author on the study. “The ability to perform correlative studies that may help discover early on if targeted therapy is working or not will potentially save a patient from enduring the wrong type of neoadjuvant chemotherapy and enable a timely switch to the right one.”

Recent Dutch research reveals, refining radiotherapy to check the growing parts of patient’s tumor that are growing faster,could regulate cancer while keeping patients to lower doses of radiation.

The device used to perform this is a form of positron emission tomography scanning called FDG PET. PET scans measure the glucose metabolism of a tumor by injecting ‘radioactive sugar’ and measuring where the radioactivity (and hence the sugar) is absorbed in the body.

Tumors have an increased metabolism compared to normal tissue, which makes them show up well on PET scans. In most cases, lung tumors are visible on PET scans as a bright sphere, with the highest intensity in the middle.

“The underlying question that motivated this study was: can we give less radiation dose to these cold spots? If it turned out that these cold areas show less signal on a PET scan because there are less active tumor cells, then the answer would be yes. However, it could also have been that the radioactive sugar doesn’t reach the cold spots for other reasons.” Dr Siedschlag explains

At the ELCC meeting, the group reports preliminary results showing that indeed in most cases the cold spots consist of dead tumor cells. In 7 out of 61 patients they saw cold spots on PET scans. Surgical examination showed that in five cases, these spots were in fact dead cells.

“The only problem in radiotherapy is minimizing the side-effects,” says lead researcher Dr Christian Siedschlag from the Dutch Cancer Institute. “If one could hit the tumor with arbitrarily high doses without having to worry about complications, all tumor cells could be killed with 100 percent certainty. Unfortunately this is not the case, therefore one must take every chance to administer no more dose than is absolutely necessary.”

“By decreasing the doses given to the cold spots, one might be able to increase the dose given to the rest of the tumor, while keeping the normal tissue dose constant. Or one could keep the dose given to the rest of the tumor constant, which would lead to less side-effects with an identical therapeutic result.”on dose to these cold spots? If it turned out that these cold areas show less signal on a PET scan because there are less active tumor cells, then the answer would be yes. However, it could also have been that the radioactive sugar doesn’t reach the cold spots for other reasons.”

University of Nebraska Medical Center (UNMC) lymphoma experts say that patients who are completely treated for lymphoma are recieving unnecessary Computed Tomography (CT) and Positron Emission Tomography (PET) examinations during their follow-up visits, often on the patient’s requests.

UNMC oncologist, Julie Vose, M.D., and co-author Malik Juweid, M.D. published their comments regarding this issue in a letter the editor in the March Edition of the ‘New England Journal Of Medicine’. They said that only a small percent of the Hodgkin’s lymphoma recurrences are diagnosed by PET/CT while majority is detected by the patient himself or during the doctor’s routine examination of the patient without imaging.

This leads to unnecessary radiation exposure and also unnecessary expediture. The radiation exposure has the risk of other cancers like lung and breast cancer.

During follow-up, physical examination, educating the patient about symtioms, routine blood tests and a yearly chest x-ray would be sufficient. Dr. Vose said that that the policy is not to do a scan unless there are symptoms or positive examination findings.

“In patients at low risk of recurrence, reducing the exposure to excessive radiation is an important goal,” she said.

The wait is over for Pakistan’s patients…no more visas, or long train travels to India to get  a PET scan done.

PET (Positron Emission Tomography) scan is considered to be a valuable tool for diagnosis, staging, treatment planning as well as follow-up of patients with cancer (not to forget the other diseases in which PET/CT scaning is valuable).  Till now, the patients from Pakistan had to go to India, Europe or Singapore for a PET scan.

Pakistan has taken a leap forward in developing its healthcare system with the installation of the nation’s first PET/CT scanner in the Shaukat Khanum Memorial Cancer Hospital & Research Centre (SKMCH&RC), with donations from local as well as foreign nationals.