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    (Original post by crazylemon)
    Sorry I was more interested in the how the tumor stops them (As a tumor will be made up of broadly the same squishy stuff as the tissue surrounding it so I can't see them just stopping dead) or whether it is a case foucusing the beam and some wave/particle duality shiz. I should probably be asking my physics friends this.....

    As for costs well we will see. 200mil buys a lot of other treatment.
    'Tis a case of giving the proton just the right amount of speed. Imagine there's a tumour 5cm deep...

    We look at the patient to see what different tissues there are between the surface and the tumour (eg, 2mm skin, 8mm fat, etc etc). We can work out how much those tissues are going to slow the thing down, eg dense tissues will slow it down more.

    Once we know how much it's going to be slowed down before it gets to the tumour, we know how much speed to give it in the first place so it gets there.

    Probably a good idea to ask your physics friends though, I'm still getting to grips with the subject
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    (Original post by Tech)
    'Tis a case of giving the proton just the right amount of speed. Imagine there's a tumour 5cm deep...

    We look at the patient to see what different tissues there are between the surface and the tumour (eg, 2mm skin, 8mm fat, etc etc). We can work out how much those tissues are going to slow the thing down, eg dense tissues will slow it down more.

    Once we know how much it's going to be slowed down before it gets to the tumour, we know how much speed to give it in the first place so it gets there.

    Probably a good idea to ask your physics friends though, I'm still getting to grips with the subject
    I understand that. I just wondered what gives it the curve of deceleration it has :p:

    I will do so. Though no doubt maths will be involved. :yuck:
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    Saw a skin graft today
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    I get a feeling, 'physios are important' isn't going to cut it with this MDT case...

    Also loling at the nursing adds TSR keeps giving me on this thread.
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    (Original post by crazylemon)
    I understand that. I just wondered what gives it the curve of deceleration it has :p:

    I will do so. Though no doubt maths will be involved. :yuck:
    aha! yeah I see your point. okay here's the equation you're after:

    http://en.wikipedia.org/wiki/Bethe_formula

    Check out equation 2... as long as we stay away from the speed of light, everything else remains constant apart from energy loss and speed^2... so like it says below, you can just treat it as energy loss is proportional to the inverse square of speed.

    So for a linear decrease in speed as would occur in water, there's an exponential increase in energy loss and hence the dose.
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    (Original post by Tech)
    aha! yeah I see your point. okay here's the equation you're after:

    http://en.wikipedia.org/wiki/Bethe_formula

    Check out equation 2... as long as we stay away from the speed of light, everything else remains constant apart from energy loss and speed^2... so like it says below, you can just treat it as energy loss is proportional to the inverse square of speed.

    So for a linear decrease in speed as would occur in water, there's an exponential increase in energy loss and hence the dose.
    Cheers. Will have a look once this MDT is out the way.
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    Just made my first real independent diagnosis: DVT in my mama.

    Got her some LMWH in A&E.
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    (Original post by Philosoraptor)
    Just made my first real independent diagnosis: DVT in my mama.

    Got her some LMWH in A&E.
    Eek. Hope she's ok (and well done on spotting it) :hugs:
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    Holy ****, this insulin lecture is just the most brain****. Anybody got any pointers? It's essentially the pharmacology of the insulin pathway.
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    (Original post by crazylemon)
    As for costs well we will see. 200mil buys a lot of other treatment.
    It's only capital costs though. The cost per treatment will therefore drop with each patient. And considering the £20,000 cost per QALY threshold automatically accepted by NICE, it won't take many patients before the NICE threshold is reached.
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    So ten weeks in and im dancing and singing to steps.
    I think i may have cracked up a term early!!!
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    Really need to sort out my cannulating technique. Can get it in the vein without too much trouble, but then navigating the one hand holding the skin tight and the one on the cannula I just ended up letting go of it at the wrong time and it just popping out of the vein.

    Any pointers anyone?
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    Dissection today - found out our cadaver had only one massive lobe making up each of his lungs. None of the demonstrators including our head of anatomy had ever seen anything like it.
    Been told to try and find out how rare it is; but can't find any info on it at all - anyone got a clue?
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    (Original post by Mushi_master)
    Really need to sort out my cannulating technique. Can get it in the vein without too much trouble, but then navigating the one hand holding the skin tight and the one on the cannula I just ended up letting go of it at the wrong time and it just popping out of the vein.

    Any pointers anyone?
    Have the confidence to advance with the needle so you're in a smidgen further before you start advancing the plastic only? Once you're fully in it shouldn't really pop back out as such unless you mean more fall out because you're using gravity so much in your positioning? Sometimes when cannulating big man veins I used to find they felt more in peril of popping out & find them trickier than some of the little-old-ladies... Are the most of the ones you've tried so far fairly 'easy' veins? Don't mean that at all in a derogatory way - as a medical student I did very few cannulas & now if I had students around & thought one was going to be tricky I wouldn't necessarily be as enthusiastic suggesting they do it - for both their confidence and the patient! Perhaps it's size of the vessel/wall related? For those huge springy veins I've found that going up in size can (seemingly paradoxically) make it easier to get them in & keep in while advancing. That needs someone doing Physics to rationalize.


    Also practice the advancing part one handed (that can be done on a dummy) so you're switching to just pushing the plastic part over with a finger rather than using a full on pincer grip like you used to get the needle into the vein in the first place. Really good in general to be practising things one handed where you can.


    Does that make sense? I suspect Renal would be a person to ask about cannula technique. I'm so spoilt these days in that I tend to be doing them with a whole MDT (nurse, play specialist etc.) & the SpRs by default often expect to do them themselves & so are pleasantly surprised if a) go ahead and try it and b) Get one in!
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    (Original post by Elles)
    Have the confidence to advance with the needle so you're in a smidgen further before you start advancing the plastic only? Once you're fully in it shouldn't really pop back out as such unless you mean more fall out because you're using gravity so much in your positioning? Sometimes when cannulating big man veins I used to find they felt more in peril on popping out (Are the most of the ones you've tried so far fairly 'easy' veins? Don't mean that in a derogatory way - as a medical student I did very few cannulas & now if I had students around & thought one was going to be tricky I wouldn't necessarily be as enthusiastic suggesting they do it - for both their confidence and the patient!) perhaps it's size of the vessel/wall related? For those I've found that going up in size can make it easier. That needs someone doing Physics to rationale.


    Also practice the advancing part one handed (that can be done on a dummy) so you're just pushing the plastic part over with a finger rather than using a full on pincer grip like you used to get the needle into the vein in the first place.

    Does that make sense? I suspect Renal would be a person to ask about cannula technique. I'm so spoilt these days in that I tend to be doing them with a whole MDT (nurse, play specialist etc.) & the SpRs by default often expect to do them themselves & so are pleasantly surprised if we get one in!
    Cheers for the reply!

    They've been pretty iffy veins at best really that I've tried on so far. Have only tried on three patients so far and one has been successful (cubital fossa vein), but not without some drama!

    The ones I tried last night (on the same patient) - twice I managed to get the first flashback, then came to a halt as what to do next as my other hand was holding back some pretty loose skin, and natural reflex told me to let go with my other hand to start advancing the cannula.

    Seems I need to practice my dexterity of this, so I can do most of it with the one hand. Will certainly keep trying, and spent some time this afternoon stabbing the fake arms.
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    (Original post by Elles)
    Have the confidence to advance with the needle so you're in a smidgen further before you start advancing the plastic only? Once you're fully in it shouldn't really pop back out as such unless you mean more fall out because you're using gravity so much in your positioning? Sometimes when cannulating big man veins I used to find they felt more in peril of popping out & find them trickier than some of the little-old-ladies... Are the most of the ones you've tried so far fairly 'easy' veins? Don't mean that at all in a derogatory way - as a medical student I did very few cannulas & now if I had students around & thought one was going to be tricky I wouldn't necessarily be as enthusiastic suggesting they do it - for both their confidence and the patient! Perhaps it's size of the vessel/wall related? For those huge springy veins I've found that going up in size can (seemingly paradoxically) make it easier to get them in & keep in while advancing. That needs someone doing Physics to rationalize.


    Also practice the advancing part one handed (that can be done on a dummy) so you're switching to just pushing the plastic part over with a finger rather than using a full on pincer grip like you used to get the needle into the vein in the first place. Really good in general to be practising things one handed where you can.


    Does that make sense? I suspect Renal would be a person to ask about cannula technique. I'm so spoilt these days in that I tend to be doing them with a whole MDT (nurse, play specialist etc.) & the SpRs by default often expect to do them themselves & so are pleasantly surprised if a) go ahead and try it and b) Get one in!
    That was my problem with one. Didn't advance needle further after flashback and the plastic buckled on the wall of the vein...
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    (Original post by Mushi_master)
    Cheers for the reply!

    They've been pretty iffy veins at best really that I've tried on so far. Have only tried on three patients so far and one has been successful (cubital fossa vein), but not without some drama!

    The ones I tried last night (on the same patient) - twice I managed to get the first flashback, then came to a halt as what to do next as my other hand was holding back some pretty loose skin, and natural reflex told me to let go with my other hand to start advancing the cannula.

    Seems I need to practice my dexterity of this, so I can do most of it with the one hand. Will certainly keep trying, and spent some time this afternoon stabbing the fake arms.

    I hate the ACF. Perhaps because spatial awareness is not my strong point... & it's not always the easiest location to feel/see what course it runs - which is what can be helpful for cannulas as opposed to venepuncture when you have more wiggle room. I'm trying to think of a time when I've cannulated there... :hmmm2:

    Getting flashback is a good start - confirmation it is indeed a vein!

    Loose skin can make it tricky. Someone once told me to try & separate in your head the piercings - think first of going through the skin then secondly into the vein because you can change course between the too. Also - really think about positioning things that might help if you have a co-operative patient. Other option can be to enlist someone to help - student nurses/HCA looking after the patient is often good for this (& you can explain afterwards to them what you were doing) - or your FY1 when you have one - once needed mine to help hold excess skin taut for me to have a try at a radial ABG before he skipped to femoral.

    Also to give a hand if you need it at a tricky stage & to give useful feedback I think it's good to have the responsible doctor with you at the time. I haven't had many medical students on firms with me but have always been there for them doing practical procedures if they're not really confident/I haven't seen them do it before - sometimes you can 'rescue' a stab (esp. w/ ABGs) if a student is flustered which saves the patient another needle in skin & I think reassures that they were close, you can give feedback after and minimize faff if trying again ASAP if unsuccessful. I guess on some firms it might be busy but you're there to learn rather than already being a fully qualified cannula/bloods monkey.
    In the other direction I find it helpful (& polite! ) to try to watch seniors do procedures that I've had to escalate up to see if there are any tips to be learnt.

    I wish you good times in the skills lab!
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    (Original post by crazylemon)
    That was my problem with one. Didn't advance needle further after flashback and the plastic buckled on the wall of the vein...
    Yeah, I think it is probably fairly common as we can get overexcited by flashback & every small movement can feel like miles! But thinking logically - the needle does poke out further than the plastic (obviously) & you want to get the plastic tube into the space rather than just blood out of the needle so you need to brave it a bit further in...
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    (Original post by Elles)
    I hate the ACF. Perhaps because spatial awareness is not my strong point... & it's not always the easiest location to feel/see what course it runs - which is what can be helpful for cannulas as opposed to venepuncture when you have more wiggle room. I'm trying to think of a time when I've cannulated there... :hmmm2:

    Getting flashback is a good start - confirmation it is indeed a vein!

    Loose skin can make it tricky. Someone once told me to try & separate in your head the piercings - think first of going through the skin then secondly into the vein because you can change course between the too. Also - really think about positioning things that might help if you have a co-operative patient. Other option can be to enlist someone to help - student nurses/HCA looking after the patient is often good for this (& you can explain afterwards to them what you were doing) - or your FY1 when you have one - once needed mine to help hold excess skin taut for me to have a try at a radial ABG before he skipped to femoral.

    Also to give a hand if you need it at a tricky stage & to give useful feedback I think it's good to have the responsible doctor with you at the time. I haven't had many medical students on firms with me but have always been there for them doing practical procedures if they're not really confident/I haven't seen them do it before - sometimes you can 'rescue' a stab (esp. w/ ABGs) if a student is flustered which saves the patient another needle in skin & I think reassures that they were close, you can give feedback after and minimize faff if trying again ASAP if unsuccessful. I guess on some firms it might be busy but you're there to learn rather than already being a fully qualified cannula/bloods monkey.
    In the other direction I find it helpful (& polite! ) to try to watch seniors do procedures that I've had to escalate up to see if there are any tips to be learnt.

    I wish you good times in the skills lab!
    Cheers again for the advice, will certainly take it on board. I've only ever attempted such things with the FY1/2 present and advising me, which certainly helps. Definitely not confident enough to do these things unsupervised yet, I'm only a baby 3rd year after all!
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    I used to go around being a bloods and cannula monkey in 3rd year - slightly to the detriment of my other clinical skills, but hey ho :p:

    I started off on young easy males (wayhey!) and then moved on to old grannies (especially ones that don't really notice what you're doing - it sounds bad but if they're not in pain it's not like you're doing it for fun they do need the cannula...)
 
 
 
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