Management of deep-seated malformations with photodynamic therapy: a new guiding imaging modality

Abstract

Photodynamic therapy is an emerging technology and results from the interactions between a photosensitiser, oxygen and light. The delivery of light may either be by surface illumination or by interstitial application. We describe the first clinical application of ultrasound-guided interstitial photodynamic therapy (US-iPDT). A total of 23 treatments with meta-tetra-hydroxyphenyl chlorine (mTHPC) and ultrasound-guided interstitial photodynamic therapy were performed on 21 patients with various conditions at the Head & Neck Centre, University College London Hospital. The needles could be clearly identified during insertion in all 23 treatments, and it was possible to guide parallel needle insertions using ultrasound. Although the resolution of ultrasound is not as high as that of other imaging modalities [i.e. computed tomography (CT) and magnetic resonance imaging (MRI)] it was satisfactory in identifying the centre and the peripheries of the pathological lesions. Ultrasound is very easy to perform, non-invasive, relatively inexpensive, quick, convenient, non-ionising, suited to the imaging of soft tissues and does not cause any discomfort. Ultrasound can be used to guide 'real-time' photodynamic therapy in deep-seated tumours and other malformations and can augment the information from other imaging modalities without affecting the patient's treatment outcome.

Photodynamic therapy in the upper aerodigestive tract. Overview and outlook

“…The studies following showed similar results concerning CR rates (ranging from 0 % to 77%) . The overall complete remission rate calculated from the mentioned studies was 29% (114/399 patients). Figure shows an example of a patient with a locally advanced adenoid cystic carcinoma of the right paranasal sinuses, who was treated with interstitial PDT under MR image guidance.…”

“…In the following years, interstitial PDT treatment was developed for tumors >1 cm and later also for metastatic disease in cervical lymph nodes. Image gui-dance was initially performed with grids and preoperative imaging, but subsequently, image guidance similar to the methods used in brachytherapy using open MRI or CT or ultrasound, have proved to be invaluable [13,[18][19][20][21]. The studies following showed similar results concerning CR rates (ranging from 0 % to 77%) [13,[18][19][20][21][22][23][24].…”

“…Image gui-dance was initially performed with grids and preoperative imaging, but subsequently, image guidance similar to the methods used in brachytherapy using open MRI or CT or ultrasound, have proved to be invaluable [13,[18][19][20][21]. The studies following showed similar results concerning CR rates (ranging from 0 % to 77%) [13,[18][19][20][21][22][23][24]. The overall complete remission rate calculated from the mentioned studies [13,[16][17][18][19][20][21][22][23][24] was 29% (114/399 patients).…”

Ultrasound‐guided photodynamic therapy for deep seated pathologies: prospective study

“…The results showed that it was possible to clearly identify the needles (inc. the tip) during insertion in all 23 treatments and it was possible to guide parallel needle insertions using ultrasound. The study concluded that it was feasible to use 2D-US to guide 'real-time' photodynamic therapy in deep-seated tumours and other malformations and can augment the information from other imaging modalities without affecting the patient's treatment outcome [7].…”

“…Short-term treatment for this is with non-steroidal antiinflammatory drugs (NSAIDs) in addition to opiates; most commonly used are codeine phosphate, tramadol and morphine; and for long-term and controlled release fentanyl and buprenorphine patches can be used. The reporting of pain mirrored a temporary rise in white blood cell levels, which followed the induction of tissue necrosis and the generation of acute and chronic inflammatory responses [1,3,7].…”