Impact of ¹⁸F-fluoride PET-CT on implementing early treatment of painful bone metastases with Sm-153 EDTMP

Spatiotemporal Statistical Shape Model for Temporal Shape Change Analysis of Adult Brain

BACKGROUND

This study presents a novel method of constructing a spatiotemporal statistical shape model (st-SSM) for adult brain. St-SSM is an extension of statistical shape model (SSM) in the temporal domain which will represent the statistical variability of shape as well as the temporal change of statistical variance with respect to time.

AIMS

Expectation-Maximization (EM) based weighted principal component analysis (WPCA) using a temporal weight function is applied where the eigenvalues of each data are estimated by Estep using temporal eigenvectors, and M-step updates Eigenvectors in order to maximize the variance. Both E and M-step are iterated until updating vectors reaches the convergence point. A weight parameter for each subject is allocated in accordance with the subject's age to calculate the weighted variance. A Gaussian function is utilized to define the weight function. The center of the function is a time point while the variance is a predefined parameter.

METHODS

The proposed method constructs adult brain st-SSM by changing the time point between minimum to maximum age range with a small interval. Here, the eigenvectors changes with aging. The feature vector of representing adult brain shape is extracted through a level set algorithm. To validate the method, this study employed 103 adult subjects (age: 22 to 93 y.o. with Mean ± SD = 59.32±16.89) from OASIS database. st-SSM was constructed for time point 40 to 90 with a step of 2.

RESULTS

We calculated the temporal deformation change between two-time points and evaluated the corresponding difference to investigate the influence of analysis parameter. An application of the proposed model is also introduced which involves Alzheimer's disease (AD) identification utilizing support vector machine.

CONCLUSION

In this study, st-SSM based adult brain shape feature extraction and classification techniques are introduced to classify between normal and AD subject as an application.

Radium-223 for the treatment of bone metastases in castration-resistant prostate cancer: when and why

Radium-223 dichloride (²²³Ra) is the first, recently approved, α-particle-emitting radiopharmaceutical for the treatment of patients with bone metastases in castration-resistant prostate cancer (CRPC) and no evidence of visceral metastases. We explored MEDLINE, relevant congresses, and websites for data on ²²³Ra and prostate cancer therapies, focusing on therapeutic strategies and timing, bone metastases, and diagnostic assessment. ²²³Ra represents the only bone-targeting agent that has significantly extended patients' overall survival while reducing pain and symptomatic skeletal events. Unlike other radiopharmaceuticals, such as strontium-89 and samarium-153 EDTMP, ²²³Ra (11.4-days half-life) has shown a high biological efficiency mainly due to its short penetration range. These features potentially allow reduced bone marrow toxicity and limit undue exposure. ²²³Ra has been validated under the product name Xofigo^® by the US Food and Drug Administration and the European Medicines Agency. Patient selection, management, and treatment sequencing is recommended to be discussed in the context of a multidisciplinary environment, including oncology, urology, nuclear medicine, and radiation therapy physicians. No consensus has been achieved regarding the optimal timing and its administration as single agent or in combination with zoledronic acid or chemotherapy, so far. This review aims to provide a rationale for the use of ²²³Ra in treating metastases from CRPC, highlighting the crucial role of a multidisciplinary approach, the disputed inclusion and exclusion criteria on the basis of agencies regulations, and the value of diagnostics for therapy assessment.

Palliative radiation therapy for bone metastases: Update of an ASTRO Evidence-Based Guideline

PURPOSE

The purpose is to provide an update the Bone Metastases Guideline published in 2011 based on evidence complemented by expert opinion. The update will discuss new high-quality literature for the 8 key questions from the original guideline and implications for practice.

METHODS AND MATERIALS

A systematic PubMed search from the last date included in the original Guideline yielded 414 relevant articles. Ultimately, 20 randomized controlled trials, 32 prospective nonrandomized studies, and 4 meta-analyses/pooled analyses were selected and abstracted into evidence tables. The authors synthesized the evidence and reached consensus on the included recommendations.

RESULTS

Available literature continues to support pain relief equivalency between single and multiple fraction regimens for bone metastases. High-quality data confirm single fraction radiation therapy may be delivered to spine lesions with acceptable late toxicity. One prospective, randomized trial confirms both peripheral and spine-based painful metastases can be successfully and safely palliated with retreatment for recurrence pain with adherence to published dosing constraints. Advanced radiation therapy techniques such as stereotactic body radiation therapy lack high-quality data, leading the panel to favor its use on a clinical trial or when results will be collected in a registry. The panel's conclusion remains that surgery, radionuclides, bisphosphonates, and kyphoplasty/vertebroplasty do not obviate the need for external beam radiation therapy.

CONCLUSION

Updated data analysis confirms that radiation therapy provides excellent palliation for painful bone metastases and that retreatment is safe and effective. Although adherence to evidence-based medicine is critical, thorough expert radiation oncology physician judgment and discretion regarding number of fractions and advanced techniques are also essential to optimize outcomes when considering the patient's overall health, life expectancy, comorbidities, tumor biology, anatomy, previous treatment including prior radiation at or near current site of treatment, tumor and normal tissue response history to local and systemic therapies, and other factors related to the patient, tumor characteristics, or treatment.

Palliative treatment of bone metastases with samarium-153 EDTMP at onset of pain

We evaluated the pain response and daily discomfort in patients suffering from a borderline degree of bone pain due to breast or lung cancer bone metastases, who had undergone early palliative radionuclide treatment. The results were compared with those from patients who had received standard analgesic therapy. Twenty-one patients (65.7 ± 3 years; 17 women) with metastatic bone cancer underwent samarium-153 (Sm-153) ethylene diamine tetramethylene phosphonate (EDTMP) administration (group A) and 18 patients (64.3 ± 8 years; 16 women)continued to receive standard analgesics (group B; control group). The patients kept a daily pain diary assessing both their discomfort and the pain at specific sites by means of a visual analog scale, rating from 0 (no discomfort–no pain)to 10 (worst discomfort–pain). These diaries were reviewed weekly for 2 months and three physicians rated the pain response on a scale from -2 (considerable deterioration) to +2 (considerable improvement). Baseline characteristics were similar in both groups. The reduction of total discomfort and of bone pain in group A was significantly greater compared to group B (p < 0.0001). A significant improvement of clinical conditions was observed in group A, where the physician rate changed from -1 to 1, compared to group B in which the rate changed from -1 to 0. Sm-153 EDTMP therapy can be considered for patients with bone pain from breast and lung cancer in advance, i.e.,before the establishment of severe pain syndrome.

Comparison of ¹⁸F-fluoride PET/CT, ¹⁸F-FDG PET/CT and bone scintigraphy (planar and SPECT) in detection of bone metastases of differentiated thyroid cancer: a pilot study

OBJECTIVE

We compared the efficacies of ¹⁸F-fluoride positron emission tomography (¹⁸F-fluoride PET)/CT, ¹⁸F-fludeoxyglucose PET (¹⁸F-FDG PET)/CT, and ⁹⁹mTc bone scintigraphy [planar and single photon emission CT (SPECT)] for the detection of bone metastases in patients with differentiated thyroid carcinoma (DTC).

METHODS

We examined 11 patients (8 females and 3 males; mean age 6 standard deviation, 61.968.7 years) with DTC who had been suspected of having bone metastases after total thyroidectomy and were hospitalized to be given ¹³¹I therapy. Bone metastases were verified either when positive findings were obtained on both ¹³¹I scintigraphy and CT or when MRI findings were positive if MRI was performed.

RESULTS

Metastases were confirmed in 24 (13.6%) of 176 bone segments in 9 (81.8%) of the 11 patients. The sensitivities of ¹⁸F-fluoride PET/CT and ⁹⁹mTc bone scintigraphy (SPECT) were significantly higher than those of ¹⁸F-FDG PET/CT and ⁹⁹mTc bone scintigraphy (planar) (p,0.05). The accuracies of ¹⁸F-fluoride PET/CT and mTc bone scintigraphy (SPECT) were significantly higher than that of ⁹⁹mTc bone scintigraphy (planar) (p,0.05).

CONCLUSION

The sensitivity and accuracy of ¹⁸F-fluoride PET/CT for the detection of bone metastases of DTC are significantly higher than those of ⁹⁹mTc bone scintigraphy (planar). However, the sensitivity and accuracy of ⁹⁹mTc bone scintigraphy (planar) are improved near to those of ¹⁸F-fluoride PET/CT when SPECT is added to a planar scan. The sensitivity of ¹⁸F-FDG PET/CT is significantly lower than that of 18F-fluoride PET/CT or ⁹⁹mTc bone scintigraphy (SPECT).