| 1. |
- Farnebo, Jacob
(författare)
-
Monitoring the effect of anti-cancer treatment in uro-oncological malignancies with molecular imaging
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the last decade, new therapies have changed the management of patients with metastatic renal cell carcinoma (mRCC) and metastatic castration resistant prostate cancer (mCRPC). Although new therapies have improved survival, drug response varies widely with some patients not responding to treatment. Unfortunately, traditional assessment of drug response with computed tomography (CT) has limitations, and novel biomarkers of treatment response are warranted in order to reduce unnecessary side-effects and costs. The general aim of this thesis was to identify imaging biomarkers that can help predict the treatment response in mRCC and mCRPC. In the first study, metabolic changes of tumour lesions detected by 18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) and CT (PET/CT) after 14 days of treatment predicted the progression-free (PFS) and overall survival (OS) in 32 patients. Metabolic response was assessed in several ways revealing that PET parameters measuring FDG uptake within a volume had stronger association to outcome than parameters based on single voxel analysis. In the second study, the benefit of repeated 11C-acetate PET/CT was evaluated retrospectively to assess response in patients with mCRPC treated with abiraterone acetate. Potential association between 11C-acetate PET/CT, serum levels of prostate specific antigen (PSA), PFS and OS were investigated. 11C-acetate PET/CT predicted PFS and OS which may be of particular clinical interest in patients who do not exhibit a PSA response to treatment. In the third study, the maximal diameter of metastatic lesions originating from mRCC as determined by diffusion-weighted magnetic resonance imaging (DWI) were compared with the corresponding measurements on CT. These measurements appeared to be in close agreement warranting for a larger trial investigating the feasibility of employing DWI in clinical trials that follow the Response Evaluation Criteria in Solid Tumours (RECIST version 1.1) guideline. In conclusion, the novel imaging biomarkers evaluated here have the ability to predict response of mRCC and mCRPC to targeted therapies, but need to be validated in a larger setting before being implemented into the clinic.
|
|
| 2. |
- Farnebo, Jacob, et al.
(författare)
-
Volumetric FDG-PET predicts overall and progression- free survival after 14 days of targeted therapy in metastatic renal cell carcinoma
- 2014
-
Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 14, s. 408-
-
Tidskriftsartikel (refereegranskat)abstract
- Background: To determine whether changes in the metabolism of metastatic renal cell carcinoma (mRCC) assessed by F18-FDG-PET after 14 and 28 days of treatment with tyrosine kinase inhibitors can predict overall and progression-free patient survival. Methods: Thirty-nine consecutive patients with mRCC were included prospectively and underwent PET examinations prior to and after 14 and 28 days of standard treatment with sunitinib (n = 18), sorafenib (n = 19) or pazopanib (n = 2). The PET response was analyzed in terms of SUVmax, SULpeak, and total lesion glycolysis and a positive response (defined as a 30% reduction) compared to overall and progression-free survival. Results: Thirty-five patients with at least one metabolically active metastatic lesion prior to treatment underwent additional FDG-PET examinations after 14 (n = 32) and/or 28 days (n = 30) of treatment. Changes in either SULpeak or total lesion glycolysis were correlated to both progression-free and overall survival (for TLG2.5 responders, HR = 0.38 (95% CI: 0.18-0.83) and 0.22 (95% CI: 0.09-0.53), and for TLG50 responders, HR = 0.25 (0.10-0.62) and 0.25 (95% CI: 0.11-0.57) and for SULpeak responders, HR = 0.39 (95% CI: 0.17-0.91) and 0.38 (95% CI: 0.15-0.93), respectively). In contrast SUVmax response did not predict progression-free or overall survival (HR = 0.43 (95% CI: 0.18-1.01) and 0.50 (95% CI: 0.21-1.19), respectively). Conclusions: Assessment of early changes in SULpeak and total lesion glycolysis undergoing treatment with tyrosine kinase inhibitors by FDG-PET can possibly predict progression-free and overall survival in patients with mRCC.
|
|
| 3. |
- Kifle, Yonatan Habteslassie, et al.
(författare)
-
NFC Powered Implantable Temperature Sensor
- 2019
-
Ingår i: 2019 41ST ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC). - : IEEE. - 9781538613115 - 9781538613122 ; , s. 4359-4362
-
Konferensbidrag (refereegranskat)abstract
- Inductively powered 99% accurate implantable temperature sensor is designed, characterized and the findings are presented in this paper. The implantable sensors deliver a continuous temperature reading to external storage or readout devices via Near Field Communication interface. A 2.76 mu H rectangular inductive coil printed on a thin biocompatible plastic substrate is designed to establish the coupling link through NFC interface with external readout devices. A commercially available wide range temperature sensor chip is mounted along with the developed inductive coil on the same plastic substrate. For 50 samples, the received signal strength indicator, temperature accuracy and statistical distribution of measurement levels is investigated. Comparison of predetermined temperature in a controlled temperature and humidity chamber versus the temperature reading from the developed sensors proves a 99% accuracy.
|
|
| 4. |
- Sandqvist, Patricia, et al.
(författare)
-
The preoperative localisation of small parathyroid adenomas improves when adding Tc-99m-Sestamibi SPECT to multiphase contrast-enhanced CT
- 2021
-
Ingår i: Insights into Imaging. - : Springer Science and Business Media LLC. - 1869-4101. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- ObjectivesTo investigate the incremental value of Sestamibi SPECT combined with a non-enhanced and contrast-enhanced CT, using SPECT/CT, for the preoperative localisation of small parathyroid adenomas (PTA).MethodsRetrospectively, 147 patients surgically cured from primary hyperparathyroidism, as verified by biochemistry 6 months postoperatively, were included. All patients had preoperatively undergone a dual time 99mTechnetium-Sestamibi SPECT (S) with multiphase CT including native (N), arterial (A) and venous (V) phases. Independently, two radiologists blinded from both the surgical and the preoperative imaging reports, sequentially performed PTA localisation starting with either [A] or [V], thereafter [A + N] or [V + N] and finally with the complete [A + N + S] or [V + N + S]. PTA localisation was reported for each image-set. The readers results were combined and the diagnostic performance for each image set was determined. Sensitivity was also calculated for the different quartiles of PTA weight distribution.ResultsThe median adenoma weight was 315 mg. No statistically significant differences in diagnostic performance between arterial and venous based image sets were found. The net effect of adding [N] was to increase specificity. Sestamibi SPECT significantly increased the overall diagnostic accuracy for arterial- and venous-based image sets, p = 0.0008 and p = 0.001, respectively. [A + N + S] was found to have the highest diagnostic performance with 86.5% sensitivity and 94.9% overall accuracy. [A + N + S] was particularly advantageous for locating PTA in the lower weight quartiles.ConclusionsNative CT-phase and dual time point Sestamibi SPECT increase specificity and sensitivity, respectively. These, in combination with a single contrast-enhanced CT-phase is the most optimal examination protocol for preoperative localisation of PTA using SPECT/CT.
|
|
| 5. |
- Wikner, Jacob, et al.
(författare)
-
Aiming for the cloud - a study of implanted battery-free temperature sensors using NFC
- 2016
-
Ingår i: 2016 INTERNATIONAL SYMPOSIUM ON INTEGRATED CIRCUITS (ISIC). - : IEEE. - 9781467390194
-
Konferensbidrag (refereegranskat)abstract
- In this paper we present results based on measurements of implantable devices which can be powered externally and communicated with using the near-field communication (NFC) infrastructure. NFC allows us to not have a dedicated gateway and intra-body communication to bridge the data from sensors to phone. In our trials, we have used commercially available sub-components and mounted them on a thin plastic with printed interconnections and coated them for bio-compatibility. Devices were implanted in porcine models during one week. We could during this time measure the in-vivo body temperature through skin and subcutaneous tissue ranging in thickness from some mm to a couple of cm. The implanted sensor devices are mounted on thin, printed-electronics plastic sheets where the coils and conductors are designed with different types of materials. The choice of materials is done in order to offer a low-cost solution to read out data from in-vivo sensors. We compile measured data, practical results and guidelines, together with theoretical results referring to the design of the implanted inductive NFC coil as well as the energy transfer from one mobile device to another.
|
|
| 6. |
- Zötterman, Johan, 1975-
(författare)
-
Laser Speckle Contrast Imaging in Reconstructive Surgery
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- ObjectivesReconstructive surgery aims to restore function or normal appearance by reconstructing defective organs after trauma or disease. In patients undergoing reconstructive surgery, previous trauma, surgery or radiotherapy can result in compromised blood supply. This will affect the viability of the tissue and increases the risk for postoperative complications, such as ischemia and infection. It is therefore important to assess the tissue viability, both before, during and after the surgery. This can be done using different techniques that monitor the perfusion of the skin covering the affected area. In this thesis, LSCI have been evaluated for tissue monitoring in reconstructive surgery. The technique allows for a fast and noninvasive assessment of superficial tissue perfusion over a wide field. Based on previous work on the technology, we have seen clear advantages with LSCI compared to other methods, for example laser Doppler flowmetry (LDF). We have evaluated laser speckle contrast imaging (LSCI) as a tool for tissue monitoring in reconstructive surgery in four studies.MethodsIn study I we used a bench top model and healthy subjects to address methodological concerns subjected to the LSCI technology. We investigated the effect of motion distance and angle on the assessed perfusion value In study II we used a porcine model to compare LSCI and LDF as tools to detect partial and full venous outflow obstruction. We used both methods to assess a flap based on the cranial gluteal artery perforator with partial and complete occlusion of the vein and artery. In study III we used the same porcine model as in study II to investigate the possibility to use LSCI intraoperatively to identify flap areas with compromised circulation and thereby predict areas with a high risk of postoperative necrosis. In study IV we used LSCI for intraoperative evaluation of tissue viability during deep inferior epigastric perforator (DIEP) free flap surgery and to investigate the perfusion distribution according to the Hartrampf zones, as measured with LSCI, in relation to the selected perforator in the deep inferior epigastric perforator free flap.ResultsIn study I we saw that tissue perfusion as measured with LSCI increases with increasing tissue motion, independent of frame rate, number of images, and tissue perfusion. Measured perfusion will decrease when images are acquired at an angle larger than 45° but distances between 15 and 40 cm do not affect the measured perfusion. In study II we observed significant decreases in perfusion during both partial and complete venous occlusion with both LSCI and LDF. However, higher variability seen with LDF, measured as % coefficient of variation. In study III a decrease in perfusion during the first 30 min after raising the flap and a perfusion value below 25 PU after 30 min was a predictor for tissue morbidity 72h after surgery. In study IV the highest perfusion values were found in zone I and higher perfusion in zone II compared to zone III, directly after the flap was raised. No remaining significant difference between zone I, II and III could be seen after anastomosis of the vessels. All flaps with a minimum perfusion <30 PU, measured after the flap was shaped and inserted, later suffered from partial flap necrosis.ConclusionLSCI is a technology that has the potential to contribute to tissue monitoring in reconstructive surgery. It has many advantages over other techniques, such as the fast acquisition time, the spatial resolution and the fact that it is completely non-invasive. However, the current system is still too bulky to be easily introduced into a clinical setting and the technology is also subject to certain drawbacks which limit its usability. It is sensitive to motion artefacts; only superficial tissue is assessed and cannot offer absolute perfusion data. If these disadvantages could be addressed, LSCI could contribute to a more accurate survey of tissue perfusion and thus better outcome in reconstructive surgery.
|
|
